Tony Forster

Wedo plugin for Turtle Art

2012-01-24T16:01:00.004+11:00

Download here a plugin for TurtleBlocks V131 (tested on OS880 Sugar 0.94) . It is a rework of a project by I.T. Daniher which has been dormant since March 2011. Here and here.

Download the file and unzip it, copy wedo-plugin to the plugins directory of Turtle Blocks (/home/olpc/Activities/TurtleArt.activity/plugins).

Known problems:
Turtle Blocks will not start unless a Wedo is connected
The distance sensor gives bad values if the motor is running

Arduino and the XO laptop

2012-01-21T19:43:00.025+11:00

The Freetronics Leostick is a low cost Arduino board. (It is presumed to be low cost, it was cheap enough to place into the satchels of the attendees of LCA2012.) The XO-1.5 already has 2 channel analogue input, an Arduino board can add a lot of extra input and output channels.

This could facilitate a number of low cost science and robotics experiments in schools, experiments at a cost suitable for developed and even developing countries.

There are a number of ways such a board could be used:

from the Arduino IDE
from TurtleArt, Firmata running on the Arduino

The second version is probably the most practical for classroom use. Once the Leosticks are loaded with Firmata (and this could even be at the factory) all that is requited is TurtleArt drag and drop programming.

Installing the Arduino IDE onto a XO-1.5 laptop (OS880)
In terminal enter the following

sudo yum install arduino

This installs an older version (0021), more importantly it installs all the dependencies including Java and avr-gcc. It is a 60MB download which expands to 200MB of storage, be warned it uses up a lot of precious space.

The IDE can be started from the Gnome menu or with the command

arduino

but it does not have the permissions to see the Arduino board on the USB serial port so start it as root (maybe why)

sudo arduino

The IDE can then be upgraded to version 1.0. This is the version recommended for the Leostick. Download version1.0 from http://www.arduino.cc/en/Main/Software
The file arduino-1.0-linux.tgz uncompresses with the Gnome archive manager. Uncompress it to a convenient location, if for example if you uncompress it to Documents, you will find a directory arduino-1.0 in this directory.

You now have 2 versions of the program, 1.0 (at /home/olpc/Documents/arduino-1.0 ) and 0021 (with components at /usr/share/doc/arduino-0021 and /usr/bin). The later versions 1.0 uses the dependencies installed with the earlier one 0021.

As described at http://www.freetronics.com/pages/leostick-quickstart-guide uncomment the following lines in /home/olpc/Documents/arduino-1.0/hardware/arduino/boards.txt

(or in version 0021 you would need to add them)

leonardo.name=Arduino Leonardo
leonardo.upload.protocol=arduino
leonardo.upload.maximum_size=28672
leonardo.upload.speed=1200
leonardo.bootloader.low_fuses=0xde
leonardo.bootloader.high_fuses=0xd8
leonardo.bootloader.extended_fuses=0xcb
leonardo.bootloader.path=diskloader
leonardo.bootloader.file=DiskLoader-Leonardo.hex
leonardo.bootloader.unlock_bits=0x3F
leonardo.bootloader.lock_bits=0x2F
leonardo.build.mcu=atmega32u4
leonardo.build.f_cpu=16000000L
leonardo.build.core=arduino
leonardo.build.variant=leonardo

Launch the Arduino IDE (sudo /home/olpc/Documents/arduino-1.0/arduino), and select Tools > Board > Arduino Leonardo.
to select the Leonardo hardware

select Tools > Serial Port
a new device appears with Leostick plugged in, dev/ttyACM0, select it.

You can now upload example programs, eg blink, to the Leostick.

NOTE: this will overwrite the program that came with your Leostick that plays a tune, watch
http://forum.freetronics.com/viewtopic.php?f=27&t=167
for the original program

Controlling the Arduino with Turtle Art
Load Firmata software into the Leostick, this can be done on an OLPC, another Linux PC or Windows. Once this is done the Leostick can be used as a I/O expander for Turtle Block drag and drop programming. No Terminal or Gnome work would be needed.

http://tonyforster.blogspot.com/2010/10/arduino-fork-of-turtle-art.html

The version here works for older Arduino boards on Sugar 0.88 It needs patching at TurtleArtActivity.py, line 834 as described in the link above. The baud rates of Turtle Art and Firmata need to be patched.

Sugar 0.88 (Fedora 11) recognises an older Arduino board as as serial device but not the Leostick. Later Arduino boards are dev/ttyACM0

This version is hard coded to dev/ttyACM0, that means it only works the first time the Leostick is plugged in and not at all for older Arduino boards. It is patched and works on Sugar 0.94.

The quick and dirty patches are:
Turtleartactivity line 835
self.palette_buttons[i].set_tooltip('thing')
line 868 commented out
# palette_toolbar_button.set_expanded(True)
serialposix.py line 273
# self.fd = os.open(self.portstr, os.O_RDWR|os.O_NOCTTY|os.O_NONBLOCK)
self.fd = os.open('/dev/ttyACM0', os.O_RDWR|os.O_NOCTTY|os.O_NONBLOCK)

see also:
http://tonyforster.blogspot.com/2010/10/turtle-arduino-display-inputs.html
http://tonyforster.blogspot.com/2010/10/turtle-arduino-digital-write.html

Turtle checksums

2011-11-09T15:07:00.006+11:00

Here is a Turtle Art program that calculates the checksum of a South American 7 digit identity number. Source. You can get the algorithm as a spreadsheet

Challenges:
How many ID numbers share a checksum?
Find 2 ID numbers with the same checksum, not by trial and error
The 'key' is 2987634, what restrictions are there on the key that could be used?
What is the effect of having the digit 0 in the key?

RGB colour addition

2011-11-05T17:08:00.005+11:00

source
Demonstrates colour addition using Turtle Blocks

Challenges:
vary the brightness of the colour circles, you could use the keyboard

XO-1.75 seismograph

2011-10-09T13:59:00.007+11:00

A seismograph program which uses the accelerometer of the OLPC XO-1.75 laptop

The x,y,z accelerometer readings are saved in boxes x,y,z. Action 1 computes long term averages for these readings, (boxes a,b,c), 5% of the current reading is added to 95% of the long term average to compute a new long term average.

Action 2 determines a threshold of random noise which is ignored. It sums the squares of the deviation from average (x-a)^2 + (y-b)^2 + (z-c)^2 . If this figure exceeds 10, the screen is turned red to indicate that an event is occuring.

Action 3 prints the sum of the squares of the deviations and the x,y,z deviations.

Project source

Challenges:

When an event occurs, graph the 3 channels (a)
Save the 3 channels events with a time stamp for exporting into a spreadsheet (b), (c)
Set up a network of laptops, an event is considered to have occured if all register it. (Use turtle position to share data)

How low can you see that the earth is curved

2011-10-04T13:20:00.012+11:00

At how low an altitude does the earth look like a disk, in other words, from how low does a line from the horizon to your eye trace out the surface of a cone (with angle a shown from the centre) ?

Surprisingly low. The depression of the horizon below level is noticable from an altitude as low as 218m. (Lysterfield Lake trig point 37°56'31" S 145°16'06" E, Elevation 218m)

View looking south east, the faintly visible Strezleki ranges are level with the line

View looking north west, the horizon is below the string

Looking east, the horizon is below the two tape markers

Looking west, the horizon is just below the two tape markers

The average depression was 7mm at a distance of 147cm

a = sin (a) for small a

a = 0.7/147 = 0.00476

r = 2h/a^2

r = 2 *218/(0.00476^2)

r = 19,000 km

Compared with the actual value of 6,371 km

Notes
Earth from space, image
Small angle formula

XO-1.75 accelerometer

2011-08-23T16:36:00.004+10:00

A turtle spirit level or plumb bob.

The 'Acceleration' block pushes the acceleration for the x,y,z axis onto the heap, this includes gravity, resolved into these 3 components. The artan of the x and y components is the angle of the line pointing towards the lowest part of the screen.

Source

An alternate solution:

East Timor continued, video

2011-07-31T12:01:00.003+10:00

(10 minutes)

Or see the short version (3 minutes)
http://www.youtube.com/watch?v=1C6Ru1hpDjk

Timor reflections

2011-07-20T15:33:00.011+10:00

Reflections on the East Timor visit
The purpose of this visit was to expand the use of the laptops. The original training had concentrated on developing computer skills. This meant that the computers were being used mainly for 'office' skills and had limited use. The goals, as understood before the visit, were to

increase the relevance to the curriculum, particularly maths
increase the use as a more creative tool

To this end, materials were developed for maths and more creative use.

Creating narratives
We are told that kids are not good at creating narratives or imaginative writing. They tend to respond only with yes/no answers. When asked to role play, they say "they made me change my name" or when asked questions they have difficulty answering in role and answer as self. If shown a cartoon of farm animals they are all called ‘toy’, not ‘pig’ or ‘horse’ (in Tetun), kids are reluctant to make ‘oink’ and ‘neigh’ noises etc.

We observed kids in prep doing imaginative play with Lego in free play time. There is also a rich Timorese oral history of poetry (eg.). It is reasonable to assume that there is innate creativity but that the types of creativity we are expecting don't match what they are culturally attuned to.

(these maybe relevant: Orality in literacy, listening to indigenous writing and Indigenous literacies - a literature review)

It is worth noting that kids are not being asked to create in their first language. The language at home is not Tetun, it is one of the other languages, possibly Mambai. The languages of instruction, Tetun and Portuguese are likely to be the second and third languages.

It is also worth noting that East Timor has only recently recovered from war.

Another possible issue, the novel didn’t appear till the 1700‘s and was then criticised as being trivial, maybe creative writing isn’t that easy and we shouldn’t be too surprised at the kids difficulty.

Possible remedies, match the task to existing forms of cultural expression. An essay on "what I did in the school holidays" might be a poor match. Get kids to first role play with Lego and then create narrative. Show short videos to catalyse discussion, virtual soccer, video games. Try oral works, music, dance, art as bridging media.

We did come prepared with some lessons which encouraged creativity but in the end mainly concentrated on math drill with Tuxmath and Gcompris, the creative lessons were too big a leap from the previous laptop use.

The original vision for OLPC was for child ownership and saturation in a situation where the education system was broken. The laptop was seen as a constructionist tool where unguided exploration would lead to experimentation and creativity. This deployment was neither child owned nor saturated. The school was functioning well and relatively well resourced.

Resources in one classroom

The feel was not dissimilar to a computer lab in a developed country. Moving from lower order skills to higher order skills (as defined in eg. Bloom's Taxonomy) is not an easy thing to accomplish in a developed world computer lab, why would it be any easier here?

1:1
Laptops will be trialed with 2 kids per laptop in grade 3, previously the larger grade 3 had not used the laptops because sharing laptops was considered impractical.

Child ownership
The children do not take the laptops home, we discussed the possibility of teachers taking the laptops home.

Child ownership can extend further than the hardware, the child can also own their learning. The laptop was 'designed for collaborative, joyful, self-empowered learning'. Tom showed the TED Hole in the Wall talk which I think had a lot of impact.

The laptops are shared between classes, each laptop has four 'owners'. The laptops are currently named 1,2,3 ... , we discussed the Chat Activity and allowing kids to rename laptops for a session.

We discussed letting the children use Chat in an unstructured, free for all way. I have done that in the past, its chaotic and challenging for the teacher but has strong benefits for literacy.

Power
Mains power is erratic and had been off most days. There is no classroom recharging, a tangled mess of leads and powerboards is impractical. Flexible furniture arrangement makes permanent power leads impractical. Multiple pendant leads are probably too expensive and still visually difficult. Need to try the laptops' automatic power management out to extend battery time.

The laptops are stored in a locked cupboard in the principal’s office. They are charged on a table in the office in a tangled mess of power boards. Laptops stacked ontop of each other could overheat. Charging is hit and miss because of unreliable power.

Laptop storage

The desk where all 20 laptops are charged

They are not left plugged in overnight, although they would charge if the power comes back on. This is maybe to reduce the risk of theft. Discussed having a lockable timber charging rack built.

http://wiki.laptop.org/go/Nepal:_Technical_Details

Other issues
There was one XO1.0. It was software locked. We could not install the intended unsigned software image.

We had been told that the Portuguese language was not required because the teachers expected computers to talk English. It turned out that was based on using the computer as an office tool. Once the range of Activities was increased, there was renewed interest in Portuguese.

The server
The school server opens up other uses, in part because it supports a directory based filesystem. Downloading the Tetun language Wikipedia now becomes practical.

East Timor continued

2011-07-17T11:44:00.012+10:00

Saturday morning

We went to Hera market in the morning.

Hera Market

In the afternoon Tom worked on the server and I tried to learn more Tetun.

The others went to Sidhara village to see a bread making demonstration.. An irrigated community garden has been established there.

Bread oven

Later we went snorkeling at Caz Bar beach, up to the big statue at Christo Rei, the supermarket and dinner at a restaurant on the beach.

Caz Bar beach, Dili

Christu Rei

The power went off at sunset and didn’t come back for 24 hours.

Sunday morning
Power still off. Up to the school to pick up 5 laptops. Ran the generator for an hour or so to cool the refrigerators and charge the laptops. Tom worked on the school server, now working if a config file on the laptops is changed. Carol and I tried out Activity sharing on an Ad Hoc network.

Sunday afternoon, church service at Sidara village.

Sidara Village

Monday morning
Tom worked on the server
Carol and I worked on activity sharing

Up to school to do Gcompris Activity with class 2A
Video

Monday afternoon Tom worked on server and I watched

The server works!!

Monday night Into dili and stayed Dayan and Merna Barbossa of WEC. Night soccer match didn't happen because power was off.

Tuesday
Off to Care this morning, in principle permission to use digitised Care resources on the laptops.

Care Dili

East Timor Laptop Deployment

2011-07-16T09:55:00.016+10:00

Hera,Timor Leste, (East Timor) 7 July 2011
Thursday Morning

Tom and I arrived in Hera yesterday. We were met by Branca at Dili airport and driven the 40 minutes to Hera.

Landing at Dili airport

Timor Leste is an island nation 1½ hours northwest of Australia. Originally a Portuguese colony, they declared independence in 1975 and were then were occupied by Indonesia. A bitter 25 year guerrilla war followed, culminating in independence in 1999. The nation was left with nearly all the infrastructure destroyed . Further unrest occurred in 2006. Timor Leste is now working to reestablish itself after this difficult past.

The population speaks a large number of local dialects, Tetun (the Tetun Dili dialect) is the lingua franca, and lesser amounts of Portuguese, English and Bahasa Indonesia. The two official languages are Portuguese and Tetun. Schooling is in both Portuguese and Tetun.

Kids Ark School, Hera, Timor Leste

The Kid’s Ark school is a P-4 school founded by Brazilian missionaries. It was given 20 OLPC XO1.5 laptops by the Seaton OLPC group in July 2010. One year later, Tom and I returned to evaluate progress and provide additional teacher training.

Two principles of the OLPC program are saturation (all primary school students in a region get laptops) and child ownership (the children get to take their laptops home). The Hera deployment is neither saturated nor take home.

It is not a saturated deployment because of lack of funding.

It was not made a take home deployment because of concerns that this was incompatible with a hierarchical society with different understandings of private ownership. The possibility of negotiating this with village elders has not been explored.

The main challenge facing us was to increase the usage of the laptops. The laptops are only being used for a few hours a week. They were enthusiastically adopted a year ago, the acquisition of computer skills was highly valued but now their feeling is that they had ‘done’ everything that could be done with the computer.

One strategy identified was to use the laptops more creatively, rather for rote type tasks.

A second was to identify linkages between the laptops and the curriculum.

Teacher's guide, 1st grade, in Portuguese and Tetun

Thursday Afternoon
In the morning we re-flashed the laptops and installed some extra activities. In the afternoon we did training of 10 mainly Tetun speaking teachers. I wasn’t much use there with my lack of Tetun language but Tom and Carol did a great job. First we did an activity inserting photos into a word processor document to create a personal profile. Then we used the Tux Math drill activity. Finally we showed Wikipedia in Tetun and discussed the possibilities.

Teaching the teachers

Friday
A positive sign, two teachers (class 2a and 2b) asked if they could use Tuxmath in their classes. We first did class 2a, that meant a bit of hurried installing of software for the class. Some kids had no idea of how to use the computer, one finger on the mousepad, enter etc. Nevertheless it took only about 20 minutes to get all the kids going well (video).

Next class 2b. Similar experience to 2a. Even more encouraging, the teacher when shown the Abacus Activity wanted to use it immediately because she could see its curriculum relevance. The kids continued to use this till the laptops batteries ran out, doubling and tripling to a laptop as the batteries progressively failed.

Linking the Abacus Activity to the existing curriculum

More to come.

Orbital motion

2011-06-14T16:05:00.007+10:00

Law of gravity

f=G ma mb/r2
a=G ma/r2
ay=a sin(theta)
ay=a y/r
ay=G ma y/r3
r=(x2+y2)0.5
ax=Gmax/(x2+y2)1.5
ay=Gmay/(x2+y2)1.5

Then for each time step
Vx=Vx+ax
Vy=Vy+ay
x=x+Vx
y=y+Vy

Source

Graphing pitch and volume

2011-05-14T12:12:00.011+10:00

Different ways of displaying pitch and (measured a little later) volume using TurtleArt

Direction = pitch, radius= volume

with only dots at the end of the line

colour determined by volume (measured a little later again)

x = pitch, y=volume

Challenges:

No code is given here, create these graphs
Make other graphs
A third variable to graph is number of occurrences of a pitch/volume pair
Can you get useful information from these graphs? Can you tell speech from music, TV program from advertisment?
The pitch block only shows the pitch of the loudest component. This is derived from a FFT (Fast Fourier Transform). Can you program a Python block to show all the spectral components and their amplitude? (Look at the source to see how the FFT is done)
With more than one laptop you can log more data. Can you combine data from multiple laptops and graph it? How will you synchronize the data?

Turtle Art and USB serial devices

2011-05-09T20:54:00.004+10:00

Using the Python block to interface with a USB serial device (tested with the Arduino)

Requires the Pyserial library. The recommended install procedure does not work because it requires a developer installation of Python python2.6-dev

Instead copy the serial directory here to the directory home/olpc/Activities/TurtleArt.activity

Load the Python block with this code

Tested on an Arduino, the Arduino had a simple echo program loaded using the Arduino IDE on another computer but this should work with any board with a FTDI FT232R USB serial chip

Ideas for controlling devices with the FTDI FT232R USB serial chip here

Turtle calculus

2011-05-08T11:54:00.018+10:00

Its easy to plug in various functions as a graph's gradient in Turtle Art. The resulting graph is the integral of the function used as the gradient. In the below case, the gradient is 1 and its integral is a straight line, f(x)=x

Plug in a linear gradient, -2+x/100, and make a parabola with zero crossings at x=0 and x=400

A quadratic gradient generates a cubic with zero crossings at x=0 and x=300

The integral of sin is -cos
(by the chain rule)

making dy/dx =y gives an exponential curve
but a nonzero value at x=0 is necessary, in this case forward 1 means f(0)=1
starting at 0, f(0)=0 has a solution of a straight line f(x)=0

Challenges
Graph for negative x
Graph the exponential for f(0)=-1 explain
The exponential above is for dy/dx = y/100 what exactly is the formula for the graph?
Find more interesting integrals
Graph the derivative of a function
Iteratively solve d2y/dx2 =-y
Explain the offset in the graph of -cos
A step size of 1 is used, what error does the step size introduce?

Nepal Micro Hydro

2011-04-24T17:48:00.011+10:00

The distribution of the OLPC (One Laptop Per Child) into the developing world including places without mains power or internet, raises the question of appropriate power technologies. A selection of small hydro schemes in Nepal below are particularly interesting in that none have road access.

Water wheel grinding cornflour
This one below Ghandruk, in the Annapurna region. There are many water mills in the region.

1 kW approximately micro hydro
Provides power for the tea house at Deurali Pass, near Ghorepani.

10 kW approximately micro hydro
This provides power for the village of Ghandruk.

Windows errors in public places

2011-04-24T17:25:00.005+10:00

My collection of Windows errors in public places:

Buenos Aires

Kathmandu

Turtle division drill

2011-04-08T12:11:00.005+10:00

Source

Challenge:
This could be turned into a 2 player online game. Writing to the screen is shared in a shared session. Add a score display and displace one player left and the other right.
Hint: you cannot remotely erase the other player's screen but you can draw a blank rectangle.

TurtleArt die or spinner

2011-04-06T15:04:00.003+10:00

Enter the number of faces (2-9) and then it tosses the die when you press a key.
source

Fractions and decimals 4th grade maths

2011-04-04T13:22:00.008+10:00

Fractions
TurtleArt project to meet outcomes 4N3 to 4N6 in the 4th grade math curriculum. Enter a single digit numerator and denominator to hit a target which is expressed as a decimal 0<1.

Open the source and paste into TurtleArt.
Could be improved with rewards and score.

Multiplication version
Source

Counting
Enter the number of balloons. If the turtle hits the top balloon, all are popped.

Source

Turtle flip and rotate, 4th grade maths

2011-04-03T17:42:00.007+10:00

An activity in Turtle Art to meet the 4th grade curriculum item "4.G.7 Describe and apply techniques such as reflections (flips), rotations (turns), and translations (slides) for determining if two shapes are congruent"

A number of shapes are randomly generated (in this prototype just a right angle triangle and a trapezium) unrotated and unflipped on the left and randomly rotated and flipped on the right. The student flips and rotates to match the two polygons.

In boxes (variables) 11 to 19, the trapezium is stored, distance, rotation, distance, rotation ... and terminated buy -1. Similarly, the triangle is stored in variables 21 to 27.

poly is a random number, either 10 for the trapezium or 20 for the triangle. Rotate is a random number, (0-7) x 45 and flip is either -1 or 1.

The program loops, waiting either a 'F' key, 102 or a 'R' key, 114. The polygon is drawn once on the left unflipped and unrotated (netflip =12 and netrotate =0) and drawn once on the right flipped and rotated (netflip = flip x userflip and netrotate = rotate + userrotate)

drawpoly draws the polygon specified in box 11-19 or 21-27 terminating on a -1 value, the polygon has rotation and flip specified in netrotate and netflip.

The activity could be improved with a score or reward system, sideways translation, more polygons and randomly congruent and incongruent pairs

Source

Broadcasting your screen to XO laptops

2011-03-21T12:38:00.012+11:00

The Activity Turtle Art can be used to broadcast an OLPC XO laptop's screen to other laptops.

In a shared session, images are reproduced on all laptops from TurtleArt V106. Enter the following code in Pippy and save:

Run the following code on the sending XO laptop in Turtle Art, click the Python block to load the Python code:

The Media block points to the screenshot image

["journal", "/home/olpc/Activities/TurtleArt.activity/screenshot.png"]

Either use this TurtleArt file , hand edit the Media block in a word processor or first run Turtle Art in Gnome (which has a file chooser instead of a journal object chooser) to set the Media block to the screenshot image.

All other laptops in the shared session will receive a screenshot every 5 seconds of the sending laptop's screen, whatever it is showing (but not the mouse cursor). Below the received image of the sending laptop's home view.

The image size and the sending interval are adjustable on the sending laptop with draggable blocks, experiment for the best results on your network.

Programming challenges:

Add a mouse cursor
break the image up into tiles and only transmit changed tiles

Singing turtle

2011-03-03T12:23:00.007+11:00

For TurtleArt on the Sugar OS

Load the Python block with the following code

The inbuilt sample code speak.py will incorporate this functionality from V107

Turtle talking clock

2011-02-28T15:38:00.005+11:00

source
Load the Python block with Speak.py (which is an inbuilt sample from V106)

Turtle Art text to speech

2011-02-23T18:37:00.008+11:00

Turtle Art can do text to speech using the Python code block. Enter the following code in Pippy. Load the code by clicking on the python block. Clicking Start will say whatever is plugged into the right of the Python block. The + operator can process strings and numbers.

The following variant from Walter avoids whole numbers (integers) being spoken with a decimal place

As at Turtle Blocks V106, this Python code is included in the inbuilt examples as speak.py

Cut off by flood water

2011-02-05T09:44:00.005+11:00

Somewhere under the water is my driveway and the bridge across the creek. I am expecting that the water will fall some time this afternoon or tomorrow. Had 165mm rain overnight, moisture left over from cyclone Yasi in the north is combining with an upper level trough and a cold front down here in the south. Last time I was flooded like this was February 2005 and my recollection was that it was called a 1 in 200 year event.

Turtle recursion

2011-01-25T10:53:00.003+11:00

It uses push and pop and is possibly a more general solution than TA's built in sample because you dont need to know the result of each recursion's calculations to restore each recursion's local variable.

http://wiki.sugarlabs.org/images/1/13/Tree_recursive.doc

Chile Patagonia strike

2011-01-18T22:28:00.004+11:00

I am told that only a handful of tourists remain in the region and that the Chilean government are moving troops into the area.

El Calafate and El Chalten in Argentina accommodation is fully booked. Many tourists need to use public buses to make ongoing connections. Most cafes and hotels require cash, ATM's are mostly out of cash..

Getting out of Chile was the right choice, its going to turn nasty.

Red Cross evacuates Chilean Patagonia

2011-01-17T01:02:00.009+11:00

Chilean army maintains order at evacuation centre

Loading buses at Red Cross evacuation centre

Saturday, the planned evacuation of Puerte Natales, scheduled for 3pm finally was underway about 10 pm. There were around 1000 tourists at the evacuation centre bound for Puenta Arenas in Chile and El Calafate in Argentina.

Both destinations were to be by air, Puenta Arenas by Chilean airforce and El Calafate by commercial flights. We did see one flight arrive and were told that it was bringing in a plane load of police and evacuating a plane load of tourists. There were only two buses at the evacuation centre for the airport and I would estimate that only half of the 400 or so destined for Puenta Arenas departed by 10pm.

There was some problem with the flights to el Calafate and the evacuation was by road convoy. There were 3 large buses and 3 small, a capacity round 180 only for 700 tourists. Boarding was based on need and the army was used to maintain order (see photo). There was some issue with the first bus which presumably carried those in greatest need and it did not depart with the others.

The convey did depart at 10pm reaching El Calafate at 3am Sunday. We passed about 6 buses on the road north from Puerte Natales but it was unclear whether they were returning from Torres Del Paine or Argentina and whether they were empty. It is likely that this provided sufficient capacity to evacuate the tourists waiting at the centre.

It is likely that the strategy was to clear the hotels and hostels in Natales so that Torres Del Paine could then be evacuated. Walkers returning from del Paine reported poor conditions there, food shortages, overcrowded refugios and unsanitary toilets.

Those walking the last 5km into Puerto Natales, Saturday morning

Red Cross give instructions, names are called and the lucky walk through the line of troops to the waiting buses (Sat afternoon)

Saturday morning, strikers at the road block north of Puerto Natales

Saturday morning, roadblock on minor road to Puerto Borries

Red Cross evacuates tourists from Patagonia

2011-01-16T04:05:00.004+11:00

Red Cross centre at Puerto Natales school

Red Cross has organised the evacuation of stranded tourists in Patagonia. Flights are leaving the airport at 3pm. The roads will be open from 3-5pm today.

Hotels in El Calafate in nearby Argentina are fully booked.

Tourists are registering at the Red Cross centre at the Natales school. Interestingly, my passport was stamped as exiting Chile so now I am in limbo.

I talked with the strikers at one of the checkpoints. Apparently, the government had proposed a 20% increase in gas prices initially but had offered to settle at 3% or CPI but the strikers rejected that offer. The strike is led by a loose coalition of industry associations including taxi drivers and fishermen.

Patagonia Puerto Natales

2011-01-15T07:54:00.003+11:00

The strike continues. Nothing is going in or out from Chilean Patagonia. The food shortage gets worse, the bar has run out of peanuts.

Wednesday night there was black smoke over the city from burning tyres. Thursday night there were 4-6 fires. We passed one checkpoint, burning tyres and a car blocked half the road. We were let past, maybe they knew our driver.

Chile Patagonia strike

2011-01-14T08:41:00.007+11:00

The extinct megafauna Miladon carries the protest flag

Chileans in Patagonia are striking in Patagonia over increases in the price of natural gas. Apparently the subsidy is being reduced/eliminated and this will create hardship for people in a cold climate and a poor area.

I am in the city of Puerto Natales and hemmed in by roadblocks. There are two routes to Torres del Paine National Park with at least 3 roadblocks between Natales and the NP. I visited two of the roadblocks today and strikers are in good spirits but less exuberant than yesterday. There is no blockade at the jetty in town but no boats are arriving or leaving. The jetty 1km north has a roadblock

Many shops and homes display black flags of support, typically garbage bags. Many cars too.

The blockade started Tuesday midnight, really a little before, we arrived 11pm Tuesday night and strikers were letting traffic through every 15 minutes or so. Wednesday morning some shops and banks opened but by midday they were closed again. Many really still trading but you had to knock on the door to get in or go to the back door. A pharmacy was trading with the window protected by shut roller shutters and a very nervous security guard on the door. Wednesday afternoon they were nearly all shut but by Thursday open again.

Hikers are being allowed back from Torres Del Paine NP but have to walk the 17km between roadblocks. Food shortages are starting, the hotel is out of diet coke and orange juice. We have heard that conditions are harder in the national park. Apparently, Red Cross have set up a shelter in the NP.

I have been told that two died at a trafficblock at Puenta Arenas yesterday in a traffic accident and that the city has no bread.

A government representative has just held a public meeting for tourists. He urged calm and suggested that tourists talk calmly to the strikers explaining their hardships as a way to help resolve the strike.

The impression is that the number of roadblocks is being increased.

Turtle Art music keyboard

2010-12-09T11:34:00.008+11:00

Press lower case a to g keys

Type the following code in Pippy and save, then load the Python block by clicking on it

Challenges:
* add an octave
* change to piano keyboard
* show music on the screen
* change note duration, see this
* save and load music, see this

source

en español

Pulse minúsculas teclas a - g

Escriba el siguiente código en Pippy y guardar, a continuación, cargue el bloque de Python haciendo clic en él

Retos:
* Añadir una octava
* Cambio de teclado de piano
* Música aparecerá en la pantalla
* Duración de la nota el cambio, ver este
* Guardar y cargar música, ver este

Turtle Paint

2010-11-22T14:42:00.006+11:00

A simple paint program written in Turtle Blocks (V104). It uses the included sample python code for push_mouse_event.py. This is loaded into the python block The rest is done with turtle blocks.

It has a tool bar consisting of a 'clean' button and 3 colour selectors. It draws straight line segments.

Additional challenges:

more colours
brush width selector
all the normal paint features

Turtle art file
open as document and paste into Turtle Blocks, (or rename from .doc to .ta outside of Sugar) load the Python block with push_mouse_event.py and then run.

Turtle Arduino digital write

2010-10-16T10:24:00.004+11:00

Turtle art source
Python code block source (Python in open doc format)

Get Turtleart Arduino working with your version of Sugar. Load the Turtle code into TurtleArt Arduino. Load the python code. Then run.
Click with the mouse to switch a digital output.

Turtle Arduino, display inputs

2010-10-15T21:03:00.005+11:00

This Turtle Art Arduino project reads and displays the digital inputs.

http://wiki.sugarlabs.org/go/File:Ard.ta

Arduino fork of Turtle Art

2010-10-15T11:45:00.023+11:00

I tried the Arduino fork (here) (or here) of Turtle Art. This version of the Arduino fork (based on V86) can co-exist with Turtle Blocks. There is another based on V80.

I first loaded Firmata into the Arduino using the Arduino software on a PC. Then I tried to control the Arduino from Turtle Art but got errors:

OS19 Sugar 0.90 fails to start TurtleArtActivity.py", line 834
OS373pyg Sugar 0.88 fails to start TurtleArtActivity.py", line 834
OS373pyg Gnome starts but fails firmata.py line 140
OS67 Sugar 0.84 fails to start permission denied opening USB0
OS67 Gnome permission denied opening USB0
OS67 Gnome (as Superuser) starts but fails firmata.py line 140
OS767 Sugar 0.82 permission denied opening USB0

Then realised that TurtleArt and the Arduino were set to different baud rates causing the error at firmata.py line 140:

I edited file taarduino.py line 5 to set the baud rate to 57600

class TAArduino(object):
def __init__(self, baud=57600):

To match the setting in Arduino Standard Firmata (loaded into the Arduino board) line 274

Firmata.begin(57600);

Thes gets Arduino working under Gnome under OS373pyg (and presumably OS67 in Gnome as superuser). The following blocks will flash the light on output 13

To get it working under Sugar (OS373pyg), and presumably Sugar 0.88 and 0.90 builds the following dirty hack worked:
TurtleArtActivity.py, line 834
replace

self.palette_buttons[i].set_tooltip(HELP_STRINGS[name])

with

self.palette_buttons[i].set_tooltip("thing")

There is another version,
http://people.sugarlabs.org/rafael/TurtleArdu.xo
This can not co-exist with Turtle Blocks, you need to uninstall Turtle blocks first.
After that it still fails on import serial on OS373pyg. Copy a serial directory from the other version
into the Activity directory gets past that bug. You also need to set the baud rate as described.

Oscilloscope

Turtle Pi (another one)

2010-10-05T16:17:00.004+11:00

see also turtle-pi

Each side is of length 500/n where there are n sides, so half the perimeter of the closed polygon is of length 500, the polygon is of perimeter 1000, the diameter is xcor

perimeter/diameter approaches pi for large n

http://wiki.sugarlabs.org/go/File:Turtle_Blocks_pi_another.ta

En español
Véase también turtle-pi

Cada lado tiene una longitud de 500 / n donde hay n lados, por lo que la mitad del perímetro del polígono cerrado tiene una longitud de 500, el polígono es el perímetro de 1000, el diámetro es coorx

perímetro / diámetro pi enfoques para n grande

Turtle Diophantine

2010-09-25T20:23:00.009+10:00

If you spend exactly 920 pesos, how many pizzas can you buy at @160 and @120
http://en.wikipedia.org/wiki/Diophantine_equation#Linear_Diophantine_equations
http://wiki.sugarlabs.org/go/File:Turtle_Blocks_Activity_Diophantine.ta

Update 26 September
Blank asks Does yours work ok with:

small $11
large $17
total $1000

Thanks for the alternate solution. Yes, my solution works for all (positive) integers. It uses repeat until rather than repeat 10 in the solution you supplied. If there are a large number of solutions, they will print off screen though.

en español in Spanish

Pippy sliderule

2010-09-13T18:25:00.010+10:00

Sliderule for Pippy on Sugar
Use arrow keys to move upper scale

Challenges:
Create more markings at useful intervals
Create alternate scales, CI, A, K, S, T, LL, Ln
Add a cursor
Mouse input
Circular sliderule
Replicate all the features at http://wiki.sugarlabs.org/go/Activities/Sliderule

source
Note blog messes up indenting

# sliderule

import pippy, pygame, sys
from pygame.locals import *
import math

# always need to init first thing
pygame.init()

# create the window and keep track of the surface
# for drawing into
screen = pygame.display.set_mode()

# turn off the cursor
pygame.mouse.set_visible(False)

color = (0, 0, 0)
bgcolor = (250,250,250)
rdisp = 0

def drawnum(posx, posy, num):
fsize = 25
msg = str(num)
font = pygame.font.Font(None, fsize)
text = font.render(msg, True, color)
textRect = text.get_rect()
textRect.centerx = posx
textRect.centery = posy
screen.blit(text, textRect)

def drawbox(rightdisp,downdisp,markdisp):
pygame.draw.line(screen, color, (rightdisp+100, downdisp), (rightdisp+800, downdisp))
pygame.draw.line(screen, color, (rightdisp+800, downdisp), (rightdisp+800, downdisp+100))
pygame.draw.line(screen, color, (rightdisp+800, downdisp+100), (rightdisp+100, downdisp+100))
pygame.draw.line(screen, color, (rightdisp+100, downdisp+100), (rightdisp+100, downdisp))
for i in range (1,10):
pygame.draw.line(screen, color, (rightdisp+700*math.log10(i)+100, downdisp+markdisp), (rightdisp+700*math.log10(i)+100, downdisp+markdisp+20))
drawnum(rightdisp+700*math.log10(i)+100,downdisp+50,i)
pygame.display.flip()

def draw2box():
screen.fill(bgcolor)
drawbox(rdisp,100,80)
drawbox(0,200,0)

draw2box()

# events
while pippy.pygame.next_frame():
for event in pygame.event.get():
if event.type == QUIT:
sys.exit()

if event.type == KEYDOWN:
if event.key == K_ESCAPE:
sys.exit()
elif event.key == 275:
rdisp += 10
draw2box()
elif event.key == 276:
rdisp -= 10
draw2box()

Turtle sliderule

2010-09-12T07:49:00.007+10:00

Turtle sliderule for Turtle Blocks on Sugar (or Gnome)
Use A and D to move upper scale

Challenges:
Complete the rectangle representing each slider
Create more markings at useful intervals
Create alternate scales, CI, A, K, S, T, LL, Ln
Add a cursor
Mouse input
Circular sliderule
Replicate all the features at http://wiki.sugarlabs.org/go/Activities/Sliderule

(note there is a redundant multiply by 1 operation to circumvent a Turtleart bug, V96, fixed in V99)

Legends and Poems from the Land of the Sleeping Crocodile

2010-09-08T16:18:00.021+10:00

AI KNANANUK HO AI KNANOIK NOUSI RAI TIMUR RAI NOUSI LAFAEK DUKUR or Legends and Poems from Timor the Land of the Sleeping Crocodile was written by Cliff Morris.

The following biography comes from A Traveller's Dictionary in Tetun-English and English-Tetun from the Land of the Sleeping Crocodile East Timor

"Cliff Morris went to East Timor as a twenty year old soldier during 1942 where he learned about the complexities of the Animist religion and to admire the Timorese people for their common human concern for all people. On visiting the island in 1973 accompanied by his son Peter, he learned how the friendship so freely given in 1942 had cost the people very dearly in the revenge carried out by the Japanese, after the departure of the Australian troops."

"He resolved to commit his life to do something of everlasting good for the people. For ten years he struggled to completing a 10,000 word Tetun-English dictionary from his own fading memory, then with the help of Paulo Quintao da Costa who authenticated the word list, it was finally published by the Australian National University in 1984 as a memorial to all those who lost their lives in Timor in the war against the Japanese. In 1983 he travelled Australia looking for people who were well versed in the story telling of the Animist religion and from this work produced a small book containing some of the village stories and poems to save them from being lost as they are probably no longer told in their country of origin."

The book, Legends and Poems from Timor the Land of the Sleeping Crocodile, has been digitised and made available, free, to schools in East Timor by the Seaton OLPC User Group and Caval. Thanks to Caval for investigating copyright and digitising at no cost.

Contents ....... 2MB pdf
Chapter 1 ...... 6MB pdf
Chapter 2a .... 7MB pdf
Chapter 2b .... 5MB pdf
Chapter 3 ...... 13MB pdf
Chapter 4a .... 6MB pdf
Chapter 4b .... 6MB pdf
Chapter 4c .... 9MB pdf
Chapter 4d .... 2MB pdf
Chapter 5a .... 8MB pdf
Chapter 5b .... 5MB pdf
Chapter 5c .... 4MB pdf
Chapter 6 ...... 1MB pdf
Chapter 7 ...... 7MB pdf
Uncorrected OCR 245kB text

2010-09-04T12:03:00.005+10:00

Software Freedom Day is an event held all over the world to celebrate and raise awareness of free software and open source software.

I will be giving a half hour talk on Sugar, the operating system of the OLPC laptop at 12:30 on Saturday 18 September 2010, at the State Library of Victoria, Melbourne Australia.

Update, 18 Sept

Photo from the event, http://luv.asn.au/sfd2010/
(thanks Jiri)

Turtle Blocks V87

2010-05-04T17:42:00.007+10:00

Turtle Blocks (previously called Turtle Art) V87 is released.

It can now do filled polygons

and has a 3 axis colour model, the 3 axes are color, shade and gray and range 0-100

Shown below, the color is represented by the angle, the shade by the radius and the successive figures (L-R) are gray = 0, 25, 50, 75, 100

The strongest colours are for shade =50 and gray = 100

Learning on mobile phones

2010-04-01T11:08:00.007+11:00

The mobile phone has been promoted by some as more appropriate learning tools for the developing world. They are present in much greater numbers than laptops are likely to ever be and they may be more appropriate technology because they address existing needs as identified by the people.

Conversely, their small screens and limited keyboards limit what can be done.

What would a good learning app for a phone look like? It need not be a visual block programming language but could be.

Authoring would be always on
Low entry, wide walls and high ceiling
Collaborative
Would give access to the microphone, speaker, camera, screen and networks (Bluetooth, Wifi and phone)
If an iPhone, it would give access to the Accelerometer, Proximity sensor, Ambient light sensor, Assisted GPS and Digital compass
It would amplify human thought

The pencil and paper amplify thought. We can create a music score, diagram or text of greater complexity on paper than we can hold in our head. The computer, like pencil and paper, allows us to store and inspect our project. Unlike paper, it also can 'play' our project. TamTam, Record, Etoys and Physics are examples that utilise the computer as a player.

The screen is how we transfer a project of great complexity inside the device to the limited representation which is inside our heads. The eye is well adapted to find a smaller piece of information in a larger project and concentrate our attention on it. Does it have to be the screen? A small screen is a problem.

The iPhone has a resolution of 480-by-320-pixels at 163 ppi , I would need glasses but its not that small a screen for young eyes. TurtleArt has a number of features which adapt it to small screens.

named stacks of blocks
collapsible stacks
zoom in and out
scrollable canvas
save and individually restore stacks in trash

Collapsed stack of blocks

Zoom (lower right)

Trash

Sugar uses the frame as a way to conserve screen space.

The Sugar frame (dark border) only visible when required

I do not think that the phone is too small a platform for serious work. I hope that somebody will create a phone app which follows the educational principles of Etoys: authoring always on, low entry, wide walls, high ceiling and collaborative. It might not be a visual programming tool though.

Turtle Sieve of Eratosthenes

2010-03-21T15:14:00.012+11:00

The Sieve of Eratosthenes is a simple, ancient algorithm for finding all prime numbers up to a specified integer. First delete the multiples of two, then multiples of three, skip 4 because it has been deleted, delete the multiples of 5 and so on.

In this program, the primes are built up visually, 0-49 in the bottom row, 50-99 in the second ...

Main calls setup which initialises 2500 integers. It then calls deletemultiple for each prime in box1 between 2 and 1250. (Student question: how far does it actually need to go?)

Setup sets up an array of 2500 variables: box (box1 +"") = 1
The value 1 is a flag that for the moment number box1 is considered a prime.
The null string "" was necessary because of a bug in TurtleArt V84.

Deletemultiple deletes multiples of box1 up to a product of 2500.
store in box (box1*box2+"")=0
marks the number as a non prime
again the null string "" is needed because of a bug in TA V84

Finally 2 stacks to plot and print the results.

Turtle_Art_Activity_eratos.ta

Septiembre 2010
En español
La Criba de Eratóstenes es un algoritmo simple, antiguo para encontrar todos los números primos hasta un número entero especificado. En primer lugar eliminar los múltiplos de dos, luego múltiplos de tres, cuatro saltar porque ha sido eliminado, eliminar los múltiplos de 5 y así sucesivamente.

En este programa, los primos se construyen visualmente, 0-49 en la fila inferior, 50-99 en el segundo ...

Main llama a la configuración que inicializa 2.500 enteros. A continuación, llama deletemultiple para cada uno de primera en box1 entre 2 y 1250. (Pregunta Estudiante: ¿hasta qué punto lo que realmente necesita para ir)

El programa de instalación crea una matriz de 2500 las variables: caja (caja 1 + "") = 1
El valor 1 es un indicador que para el número momento box1 se considera un número primo.
La cadena vacía "" era necesario debido a un error en TurtleArt V84, probablemente no necesita.

Deletemultiple elimina los múltiplos de box1 hasta un producto de 2500.
almacenar en la caja (caja 1 * BOX2 +"")= 0
marca el número como no principales
otra vez la cadena vacía "" era necesaria debido a un error en AT V84

Por último dos pilas para trazar e imprimir los resultados.

Mouse support in TurtleArt

2010-03-20T15:09:00.020+11:00

Here is how mouse support can be added to Turtle Art V84. In this example, mouse left click events are registered by setting a flag, the x and y at the mouse click can be read.

[note as of Turtle Blocks V87 no patching of tawindow.py is required and the python block code is in the sample myblock file]

It requires some modification of the program code, three new lines need to be added to the file tawindow.py near the beginning:

def __init__(self, win, path, parent=None, mycolors=None):
self.mouseflag=0
self.mouse_x=0
self.mouse_y=0
self.win = None

and three new lines about 1/4 way into the file:

def _buttonpress_cb(self, win, event):
""" Button press """
self.window.grab_focus()
x, y = xy(event)
self.mouseflag=1
self.mouse_x=x
self.mouse_y=y
self.button_press(event.get_state()&gtk.gdk.CONTROL_MASK, x, y)
return True

These changes are necessary so that the programmable block tamyblock.py can "see" the mouse event. Turtle Art's files can be modified with Browse and Pippy or with the Linux command line editor vi see Modifing_an_Activity

Then a bit of code in the programmable block tamyblock.py makes it all happen.

def myblock(lc, x):
if lc.tw.mouseflag==1:
lc.heap.append(lc.tw.mouse_y)
lc.heap.append(lc.tw.mouse_x)
lc.heap.append(1)
lc.tw.mouseflag=0
else:
lc.heap.append(0)
return

Help understanding the detail of Turtle Art's internal Object Oriented Python programming is at Python_code_block

File:Turtle_Art_Activity_mouse.ta

(note: blog does not preserve indents, correct Python indenting is required)

Turtle spirograph

2010-03-15T19:56:00.007+11:00

The following version displays the formula, it also shows that the formula for a python block can be a variable (and could be modified during execution)

File:Turtle_Art_spirograph.ta

Septiembre 2010
En español

La siguiente versión de la fórmula, sino que también muestra que la fórmula de un bloque python puede ser una variable (y podría ser modificada durante la ejecución)

Programming and Mathematics understanding

2010-03-09T06:35:00.030+11:00

Logo was the first programming language created for teaching mathematics. Later came programming languages, which can be described as iconic, visual or drag and drop. They are also promoted as ways for children to better understand mathematics concepts. These programming languages include Scratch, Etoys, Turtle Art, Gamemaker and more.

Logo, (by Papert and others), was originally used to control real turtle robots which left pen trails on paper, later the turtle and pen became virtual. Logo was text based rather than visual, this limited it uptake in schools.

image http://museum.mit.edu/150/items/2007.019.001.jpg

Scratch, Etoys, Turtle Art and Gamemaker, which are discussed here, use visual blocks rather than text and are essentially syntax free, giving students more time to concentrate on higher level tasks than syntax error correcting.

It is thought that the use of these programming languages, before or during the formal teaching of mathematics concepts, will transfer to improved mathematics understanding as well as higher order thinking and problem solving skills. This is based on a constructivist understanding of learning, that learning is highly individualised and that multiple representations of a concept are more likely to meet individual learning needs.

Here I look at some basic mathematics ideas: number, equality, addition and functions to see how the visual representations match the mathematics concepts and might aid understanding.

Number line
Number can be visualised as movement along a line. Moving forward, along with turning, also create geometric shapes.

Subtraction on a number line can be visualised by walking forward then back a number of steps. All languages except Game Maker handle this well. Turtle Art has an advantage with negative numbers.

Scratch

Etoys

Turtle Art

By having a "back" block, Turtle Art allows the operations of addition and subtraction of positive and negative numbers such as -1-(-2) =1, forward(-1) back(-2) = forward(1)

Game Maker

Game Maker evolved as a game creation tool rather than being created as an educational tool, it does not easily do pen trails or easily move incrementally forward. It does handle addition of velocities well though.

Equality
The equals sign has 3 meanings
The equation, an assertion of equality 3+5=5+3
Assignment, let x=5
Testing, if x=5

Assignment
The coordinate of the Turtle can be assigned a new value, implicitly as above or explicitly. The Scratch block is a representation of a verbal or written instruction. The Game Maker one is also text based. The Etoys representation does use a back arrow to denote action and is better, though it is a bit crowded with selector hotspots.

The Turtle Art block is the one more likely to be useful to the learner, giving a clear visual cue to assignment.

Scratch

EtoysTurtle Art

Game Maker

Binary arithmetic operator, addition
Addition is the first function which children encounter.
It can be written as infix, 2+2, prefix + 2 2, or postfix 2 2 +
In mathematics it is written in infix notation. Early scientific calculators used postfix. Turtle Art uses prefix, the other three languages infix.

Though infix notation is more consistent with the way equations are written in mathematics, prefix notation gives a better understanding of what is happening, that the + operator combines two values to give a third.

Scratch

Etoys

Turtle Art

Game Maker

More on number
Rational numbers can be represented as fractions or as decimals.

Scratch's "say" displays 2 decimal places

Etoys' watchers can display and edit data at run time, the number of decimal places is alterable. Etoys is the clear winner in this category.

Game Maker's "draw text" and "display message" display to 2 decimal places.

Turtle Art's "show" and "print" display 2 decimal places.

Function
The current understanding of a function is relatively new. A mathematics function is currently understood as a many to one mapping from a domain to a range.

A programming function is more understood as a process which takes an input and produces an output (without overwriting the input). It can be thought of as a machine or a black box with input and output.

Scratch and Etoys have a function box which allows selection from a limited drop down list of functions. Game Maker allows functions to be typed in from a very extensive range of scripting language which is documented in help. Turtle Art allows the use of Python functions which are poorly documented.

Only Turtle Art allows the function to be visualised as an input/output machine.

Scratch
Etoys

Turtle Art

Game Maker

Conclusions
Though a large number of teachers support the use of these languages for learning mathematics concepts and problem solving skills and though it seems likely that the benefits are realised, there is virtually no hard evidence of any of these benefits. This is not because the experimental data fails to support these beliefs but rather because there is no experimental data.

Neither is there any solid theoretical basis for preferring one kind of visual representation over another. There is poor understanding of how maths concepts are learnt and virtually none of how these alternate visual representations interact with this learning, either helping or hindering.

I do expect but cannot offer proof that:

Turtle Art's ability to do "back" gives the opportunity for more complex number line concepts
Turtle Art and Etoys' plug in metaphor is a good way to conceptualise assignment
Turtle Art's prefix notation is a better way to visual binary operators
Etoys' variable watcher with editing on the fly and variable decimal places is a good way to visualise number and variables
Turtle Art's visualisation of a function as an input/output machine or black box is a good way to visualise a function but it is limited by poor documentation

This comparison of features is not intended as an endorsement of one language over another. Other important factors are the affective (or fun), flow, low entry, wide walls and high ceiling.

Hailstorm hits Melbourne

2010-03-06T15:50:00.005+11:00

Damage to the veranda at home

Turtle file save

2010-03-02T22:21:00.006+11:00

Turtle Art can now save svg images to the journal. This program saves a red box as a svg image.

The filename can be a variable and concatenated from strings and Python functions.

Turtle Pythagoras 2

2010-02-22T18:30:00.014+11:00

A proof of Pythagoras' theorem in Turtle Art

Cannot get the colour fill as above though

The following may be a better representation. Student challenge, program the following:

Image http://en.wikipedia.org/wiki/Mathematical_beauty

See also Turtle Pythagoras
See also implementation in Game Maker

To do: Python block does not accept box(theta) as input

Turtle e

2010-02-21T12:53:00.007+11:00

Calculation of e using the Taylor series

http://en.wikipedia.org/wiki/E_(mathematical_constant)#Complex_numbers

(Turtle Art seems to now only display one decimal point at V83 so I have scaled up by 10^12 to show decimal places, Previous example of Pi showed decimal places)

Student challenge: calculate square roots with the Taylor series

http://en.wikipedia.org/wiki/Methods_of_computing_square_roots

File:Turtle_e.ta

En español
Cálculo de correo utilizando la serie de Taylor

(Turtle Art muestra limitada decimales por lo que han ampliado en un 10 ^ 12 para mostrar más cifras decimales, el ejemplo anterior de Pi mostraron cifras decimales)

Estudiantes desafío: calcular raíces cuadradas con la serie de Taylor

Turtle Art - collapsed stacks and numeric input

2010-02-14T13:45:00.007+11:00

Turtle Art now has the ability to collapse a stack of blocks, shown expanded above and collapsed below.
That, along with copy and paste, allows you to develop a handy set of stacks, like subroutines, for later reuse, which do not complicate program readability or use screen space.

The stack above captures a multi digit integer from the keyboard and returns with it in Box1 when enter is pressed. The digits 0-9 have a key value of 48 to 57. The enter key has a value of 13.

Turtle_Art_getnumber.ta

En español
septiembre 2010

Turtle Art tiene ahora la posibilidad de contraer una pila de bloques, que se muestra ampliada por encima y por debajo se derrumbó.

Eso, junto con copiar y pegar, le permite desarrollar un conjunto útil de las pilas, como subrutinas, para su uso posterior, que no se complican la legibilidad del programa o espacio en la pantalla uso.

La pila por encima de captura un número entero de varios dígitos desde el teclado y vuelve con él en el Cuadro n º 1 cuando se pulsa ENTER. Los dígitos 0-9 tiene un valor de clave de 48 a 57. La tecla Enter tiene un valor de 13.

Turtle Art - higher ceiling

2010-02-07T19:40:00.005+11:00

A good learning environment for self-directed learning has a low entry, wide walls and high ceiling. That is, it is easy for beginners, can facilitate a wide range of creative efforts and is unrestricted in top end complexity.

Turtle Art for the Sugar operating system started out as a nice little, Logo like, drawing package
for young learners. Its Turtle and Pen pallets allowed young learners to draw geometric shapes, solve problems and learn a bit about geometry and logic.

Its Scratch like interlocking program blocks made programming foolproof.

Maybe a year ago, Walter Bender introduced the Portfolio pallet, which allows the integration of multimedia into this simple programming language. This extended the use of Turtle Art into literacy activities.

Python programmable blocks were also added, this extended the ceiling, there was no effective limit to the top end functionality. There is however a big leap from drag and drop progam blocks to object oriented Python which limits the usefulness of these blocks.

Recently Walter and Raúl Gutiérrez Segalés have done a major rewrite of Turtle Art, the pre-release version (at the time of writing), version 83 is here. Variable names and block stack (subroutine) names are now themselves variables. These variables can be numeric or string and the + operator can concatenate both data types. This greatly increases the power of Turtle Art while staying with familiar drag and drop block programming.

The program shown above above creates a 10x10 array of variables. The variable "index" contains a string RnCm where n and m are the row and column. The variable "index" is used to name 100 variables named R1C1 to R10C10 which have the value Row x Column stored in them.

A variable "subroutine" or stack name is also used. On the first pass, "runarray" calls stack "doit" to create the array and initialise the array values on the second pass it calls stack "printit" to display the array values.

Now a wide range of sophisticated programming is possible. For example, Turtle Art could compute fractals but the slow execution of the underling Python interpreted language is a major limitation.

Maths Wars

2010-02-01T18:34:00.005+11:00

http://commons.wikimedia.org/wiki/File:Euler%27s_formula.png

"Maths Wars" refers to the tension between instruction and construction in teaching/learning

The following interesting quote came via Artichoke

"Many of those wanting to build relational understanding with students assume that spending time on rote procedural knowledge is an important precursor for developing deeper conceptual understanding. This seems like a common sense approach – a let’s keep a foot in both camps kind of approach. However, research findings in math education suggest otherwise (Pesek and Kirshner 2000). It seems more likely that, in maths education at least, time spent building prior instrumental understanding is an interference to, not an aid to, developing relational understanding."

Interesting because Australia schools at least seem to spend a lot of time on rote procedural knowledge in mathematics.

More on Pesek and Kirshner 2000

"Students who received the procedural instruction prior to the conceptual instruction learned less than did students who received only the conceptual instruction. Somehow, exposure to routine application of formulas inhibited or interfered with students' subsequent conceptual learning."

It still seems likely to me that the best teaching will incorporate both solid procedural knowledge and problem solving in authentic and relevant contexts. This study does not destroy that belief, but it does sound a warning that you can't just mix a bit of both and always get good results.

Turtle interactive multimedia

2009-12-15T15:08:00.009+11:00

In my previous post I speculate on the significance of authoring interactive multimedia in developing a critical literacy in new media.

Here is an excercise in Turtle Art which mixes the authorship of game and presentation. The intention is that it should raise questions in the author of intended audience, bias, rational and emotional appeal, the relationship of author and viewer in nonlinear media, sound, motion, colour etc.

It is a bare bones example of mixing turn based game and multimedia, based round a global warming theme.

The consumer is presented with multimedia (can be still image, video, audio) and answers y or n to whether they want to take action on global warming, depending on their response they are presented more multimedia or asked whether they want to use nuclear energy, depending on response they get more multimedia. They also get the choice to quit or play again

Computer programming and the acquisition of critical literacy

2009-12-15T08:14:00.011+11:00

I present the following argument for the authoring of interactive or programmable multimedia as an important meta-literacy skill. Though I am not fully decided on this proposition or the role of critical literacy in schools, I think the issue is significant and worthy of consideration.

In summary:

Critical literacy is an important skill
Literacy is not just about text and can apply to a range of non-text media
Non text media are becoming increasingly important means of communication
Despite their apparent skill with the new media, students still need help developing critical literacy in new media
Media authoring skills are necessary for developing critical literacy
Media are increasingly becoming interactive
Hence authoring skills of interactive or programmable media are an important literacy skill

Meta literacy or critical literacy

Critical analysis is an important literacy skill. When applied to traditional media, it means not just comprehending the words on a page but assessing the truth and reliability of the writing and understanding the motives and biases of the writer.

“Critical literacy is the defining aspect of meta-literacy. The literate person examines texts to determine the currency, accuracy, bias, and comprehensiveness of the information. It means taking our thinking to a deeper level with critical questions.” (Doiron 2005)

Edgar Dale, well known among a earlier generation of educators and researchers for his work related to literacy, discussed the need for critical reading, listening, and observing in contending with the new literacies implied by audiovisual media of the 1940s.

“The new literacies of the Internet and other ICTs include the skills, strategies, and dispositions necessary to successfully use and adapt to the rapidly changing information and communication technologies and contexts that continuously emerge in our world and influence all areas of our personal and professional lives. These new literacies allow us to use the Internet and other ICTs to identify important questions, locate information, critically evaluate the usefulness of that information, synthesize information to answer those questions, and then communicate the answers to others.” (Leu et. al.)

New literacies

Literacy is not, and never was, just about written text. Literacy is about conveying meaning through the use of symbols, these symbols are most commonly text but not always. Even early manuscripts were illustrated and diagrams are an important part of technical texts (Lemke).

Nor is text literacy just about the literal meaning of words. Poetry and drama are used to convey nuances of meaning that prose cannot convey. Understandings of literacy have changed over time, the novel is only about 400 years old and was controversial when first introduced.

Other media greatly enhance the meaning of text, they don't just add to it. “Meanings in multimedia are not fixed and additive (the word-meaning plus the picture-meaning), but multiplicative (word-meaning modified by image-context, image-meaning modified by textual context), making a whole far greater than the simple sum of its parts “ (Lemke)

Nor is prose that simple, meanings can be modified by tone of voice, orthography and calligraphy. Text can be communicated in sign language.

programmable multimedia in Turtle Art

Typological and topological

Lemke draws the distinction between typological and topological symbol systems. Typological systems (language) work more through classification into mutually exclusive categories whereas topological systems including maths and visual media work at the level of variation and relationship. Critical literacy is required with typological and topological media.

Electracy

The word electracy has been coined to describe the 'kind of 'literacy' or skill and facility necessary to exploit the full communicative potential of new electronic media such as multimedia, hypermedia, social software, and virtual worlds.” (Wikipedia)

Social media

Blogs, wikis. Myspace, Facebook, Youtube, Twitter, Skype, Ventrilo, SMS, IM, listservers, Secondlife, etc. are interactive rather than broadcast media. They are increasingly becoming the media through which citizens inform themselves. They are also increasingly channels for business communication.

For example, the most up to date news of the 2004 Tsunami was provided not by the mainstream media but by blog sites.

Social media also played an important role in the 2009 Australian bushfires. “As the worst bushfires in Australia's history raged across Victoria, Twitter, Flickr and Facebook lit up with condolences and horrific first-hand accounts, while many used innovative online mapping tools to assess the risk of the fires reaching their own homes. Mainstream news outlets, battling to provide comprehensive coverage of the tragedy, have incorporated accounts published on the social networking sites extensively in their reports.” The Age February 9 2009,

Political parties are using Youtube and blogs to communicate their messages.

Digital Natives

Digital natives grew up in the age of computers. It is often said that they are much more proficient in digital media than their teachers. How then can they be taught about digital media? Livingstone, among others, questions how deep their apparent proficiency is, quoting Scanlon he says “education ought to be based on assessing students’ individual strengths and weaknesses rather than making glib generalisations that mistake using Facebook for technological savvy”

Leu outlines a role for teachers, “Teachers will increasingly need to orchestrate complex contexts for literacy and learning rather than simply dispense literacy skills, since they will no longer always be the most literate person in the classroom.”

Authoring skills

Authoring is an important part of literacy. If this is true for text, would it not also be true for multimedia?

“Literacies cannot be understood as passive receptivities. Making sense with a printed text is a complex and active process of meaning-making not so different from writing the original of that text “ (Lemke)

The generic literacies of the Information Age will certainly include: multimedia authoring skills, multimedia critical analysis, cyberspace exploration strategies, and cyberspace navigation skills. (Lemke)

“Jamie Myers and colleagues described in 1998 how involving students in creating multimedia hypertexts about literacy and historical figures such as Pocahantas led to a critical stance toward various sources of information”(StateUniversity.com)

"Our proposal for a multimedia literacy that gives the ability to participate freely in the society of the third millennium, and ultimately to transform it, stems from students and teachers authoring multimedia." (Gutiérrez Martin)

Interactive media, simulations and games

Increasingly, interactive media including games are used to inform and persuade. Critical literacy skills also apply to this medium. Some examples of “serious games” include:

Americas Army, “America's Army (also known as AA or Army Game Project) is a series of video games and other media developed by the United States Army and released as a global public relations initiative to help with recruitment”. (Wikipedia)

Food Force is an Educational game published by the United Nations World Food Programme (WFP)

Darfur is Dying is a viral video game for change that provides a window into the experience of the 2.5 million refugees in the Darfur region of Sudan

Ayiti: The Cost of Life , produced through Global Kids and supported by Microsoft's Partners in Learning Mid-Tier Initiative, which “seeks to identify and encourage "pockets of innovation" for increasing digital literacy and career readiness”.

Virtual Worlds

Virtual worlds include Secondlife, World of Warcraft and Quest Atlantis. Virtual worlds are inhabited by the avatars of large numbers of real people, there is a lot of interaction and a lot of communication, some of it language based and some not. It is likely that we will be spending increasing time in virtual worlds for work and play and that a critical literacy will be desirable.

Secondlife is not a game, but it is a game-like virtual world. deWinter and Vie have written on using Second Life to teach critical media literacy.

The multiplayer game and virtual world, World of Warcraft now has over 10 million subscribers making it larger than many countries. “World of Warcraft is rich in new literacy practices as there are so many other players online around the world at the same time” writes a teacher . Beavis discusses how a World of Warcraft trailer was critically analysed by a class of year 8 students.

Quest Atlantis is a learning and teaching project that uses a 3D multi-user environment to immerse children, ages 9-15, in educational tasks. The literacy aspects of this virtual world are many and obvious.

Visual programming languages

Multimedia is becoming increasingly interactive. The media experience changes depending on consumer choices. The webpages we view change their content based on tracking cookies. The authoring of web pages is computer programming. We regularly interact with web aplets, games and simulations. Even entering phone numbers and ring tones to our phones is programming, when we change our computer wallpaper we are programming. When we set up a spreadsheet or word processor template we are programming.

The ability to write computer programs is an important authoring skill and as has been argued above, requires a critical literacy.

Multimedia authoring tools are increasingly interactive and programmable whilst programming languages are increasingly accessible to younger learners and allow the embedding of multimedia: images, video and sound.

For example, Powerpoint, which is primarily a slideshow authoring tool can be used for games and animations. And game programming tools can be used to author presentations.

For students to learn to author interactive media and multimedia, they don't necessarily have to do all that with one package, they could use one package to author multimedia and another for interactive media, but it does seem like a good idea if they can blend both in one package.

Multimedia in a Turtle Art program

The desirable features of an authoring system in which students can develop multimedia critical literacy are

can present a range of multimedia, sound, images and video,
can create interactive media
low entry ( easy for beginners )
high ceiling* ( no restrictions for high level tasks )
free**, if students are given authentic and relevant challenges they will spend many hours working at home for each class contact hour

* closely related to high ceiling is the concept of wide walls, that is that students are unrestricted in the breadth of their project as well as being unrestricted in top end complexity

** related to zero cost is software freedom, open source software can be modified or remixed by teachers and students, aside from the question of whether schools should lead by example or reflect the realities of commercial software, there is a case that the ability to inspect and modify is part of developing multimedia authoring skills.

The characteristics of some popular programmable authoring environments are shown below

	Low Entry	High Ceiling	Open Source	Free	Text/graphic
Turtle Art	Y	N	Y	Y	graphic
Etoys	N	Y	Y	Y	graphic
Game Maker	Y	Y	N	Y (lite version)	graphic
Scratch	Y	N	Open source closed development	Y	graphic
Kahootz	Y	N	N	N	graphic
Flash	N	Y	N	N	text
Agent sheets			N	N	graphic
Powerpoint			N	N	graphic

References

Alfonso Gutiérrez Martín PhD. Multimedia authoring as a fundamental principle of literacy and teacher training in the information age University of Valladolid (Spain) edu.of.ru/attach/17/1382.doc

Lemke, J.L. Metamedia Literacy: transforming meanings and media, in Literacy for the 21st Century: Technological Transformation in a Post-typographic World, D. Reinking et al. (Eds.), Erlbaum.

Ray Doiron and Jessie Lees It Takes a Village to Raise a Reader: Building Literacy Across Generations http://www.nald.ca/library/research/village/report.pdf September 2005

Dale, quoted in Literacy - Multimedia Literacy http://education.stateuniversity.com/pages/2186/Literacy-MULTIMEDIA-LITERACY.html

Donald J. Leu, Jr. Charles K. Kinzer Julie L. Coiro Dana W. Cammack Toward a Theory of New Literacies Emerging From the Internet and Other Information and Communication Technologies http://www.readingonline.org/newliteracies/leu/

MMOGCHART.COM “Charting the future of the MMOG industry.” http://www.mmogchart.com/Chart1.html

Jennifer deWinter and Stephanie Vie Press Enter to “Say”: Using Second Life to Teach Critical Media Literacy

Beavis Paying attention to texts http://www.aate.org.au/files/documents/English%20in%20Australia/Beavis%20EinA%2043-1.pdf

Kahootz3 at forefront of research http://www.une.edu.au/creme/uploadedfiles/kahootz_newsletter.pdf

Turtle fractions

2009-12-13T12:58:00.007+11:00

For Turtle Art. Change the numerator and denominator, then run it to see a pie chart

TA project file for TA V84

Septiembre 2010
En español
Cambiar el numerador y el denominador, a continuación, ejecútelo para ver un gráfico circular

Turtle Pi

2009-12-13T09:31:00.009+11:00

Pi calculated by the Gregory-Leibniz series in Turtle Art

(image http://en.wikipedia.org/wiki/Pi)

Turtle_pi.ta

Septiembre 2010
En español

Turtle graph

2009-12-12T21:59:00.007+11:00

For Turtle Art. Edit the math equation (Python code)

in the equation block and graph the result.

Project File Turtle_graph.ta (for a later version V84 than shown above)

Turtle Pythagoras

2009-12-11T16:07:00.004+11:00

For Turtle Art
The function block reads 180*atan(x)/pi

see also Turtle Pythagoras 2

Bouncing turtle

2009-12-11T11:43:00.003+11:00

For Turtle Art

TurtleArt_bounce.ta

Turtle random V2

2009-12-11T10:30:00.010+11:00

Uses Turtle Art to simulate repeated trials of n (25) coin tosses, for large n and a large number of trials, the normal bell shaped distribution results.

Utiliza Turtle Art para simular la repetición de pruebas de n (25) lanzamientos de la moneda, para n grande y un gran número de ensayos, la campana en forma de resultados normales de distribución.

(Has been also done with Game Maker)

Uses the Python code block to hold coding for the n bins. Use Pippy to edit the Python code.
Load the Python code into your block with the load my block button:

def myblock(lc,x):
....n= int(lc.heap.pop(-1)) #n number of bins
....bin=[0]*n # set up array size n
....if x ==-1: #-1 initialises heap
........for i in range (n):
............lc.heap.append(0)
....else: #!=-1 so is a real trial
........for i in range (n):
............bin[i]= lc.heap.pop(-1)
............if i==x:
................bin[i]+=1
........for i in range (n):
............lc.heap.append(bin[i])
........for i in range (n):
............lc.heap.append(bin[i])
....return

Update September 2010
This version, in Spanish, uses multiple turtles for a simple solution
Esta versión, en español, utiliza las tortugas múltiples para una solución simple

*.ta source load this source and the block labels will display in the language set on Sugar.

Turtle random

2009-12-09T16:44:00.005+11:00

Note: random(0,2) returns an integer less than 2, ie 0 or 1 on older versions of TA, for V99, random(0,1) returns 0 or 1

Redone for Turtle Blocks V99 October 2010

Source

en español

Turtle Lissajous

2009-12-09T14:00:00.004+11:00

x=sin(t)
y=sin(3*t+pi/2)

Turtle_Art_lisajous.ta

October 2010 for Turtle Art V99
(en español)

Turtle spring damper

2009-12-09T13:05:00.011+11:00

Simple harmonic motion with Turtle Art.
For each time step
y = y + speed
speed = speed + acceleration
acceleration = -k1*y -k2*speed

where
k1=1/400 = springconstant/mass
k2=1-0.996=0.004 = damperconstant/mass

Turtle_spring_damper.ta

Septiembre 2010
En español

Movimiento armónico simple con Turtle Art.
Para cada paso de tiempo
y = y + velocidad
velocidad = velocidad + aceleración
aceleración =-k1 * y - k2 * velocidad

donde
k1 = 1 / 400 = constante del resorte / masa
k2 = 1 - 0,996 = 0,004 = constante del amortiguador / masa

xo australian deployments

2009-10-01T13:49:00.002+10:00

Software Freedom Day 2009 - Melbourne

2009-09-19T16:31:00.006+10:00

Software freedom day Melbourne

Demonstrating Sugar educational software on XO laptops running Sugar and conventional laptop with Sugar on a Stick (SoaS)

Squeak presentation - Tansel Ersavas

Going back to Lajamanu

2009-09-15T09:08:00.008+10:00

Image http://wiki.laptop.org/images/4/4d/P1020317-1.JPG

The OLPC (One Laptop Per Child) is designed to provide learning in a student's native language,

"OLPC's target population of schoolchildren live in nearly 200 countries, where more than 6,000 languages are spoken. The 100 most common languages would suffice for reaching 99%+ of children in first or second languages, but hundreds more would be needed for education in traditional cultures and languages of large populations. OLPC can play a large part in recording and preserving thousands more languages before they would otherwise disappear forever. "
http://wiki.laptop.org/go/Localization

The Australian Broadcasting Commission's Four Corners program Going back to Lajamanu can be viewed online.

It examines the history of bilingual education in Australian aboriginal schools. Bilingual education has had a difficult history with varying levels of support from state governments. It is now all but abandoned with English being mandated for the first 4 hours of the school day.

The program tells how the then school principal narrowly avoided being dismissed for participating in an indigenous ceremony. It also describes (17:00) how indigenous teaching assistants have been downgraded from teachers to translators under the state education policy.

The education minister (13:50) and the head of the education department (16:00) describe the policy of instruction as being 'explicit' about English but seem to have difficulty explaining how to be 'explicit' about the English language . 'Explicit' is also linked with benchmarking. It is evidence of the terminology of explicit or direct instruction and may indicate that the education department is at one swing extreme in the pendulum of instruction/constructivism in the 'curriculum wars'.

The 4 corners program gives valuable insight on how the OLPC may or may not be used for learning in students' first language.

PS
Very funny at 18:00 where the kids are tasting spices as part of science.

Turtle Art, color and shade

2009-09-14T13:17:00.003+10:00

See http://xo-whs2009.blogspot.com/2009/09/turtle-art-using-heading-to-change.html

Turtleart shapes

2009-09-04T21:42:00.006+10:00

Bill Kerr promotes Barry Newell's worksheet of turtle shapes at http://billkerr2.blogspot.com/2009/08/40-maths-shapes-challenges.html

Here's one shape in Turtle Art.

Visual thinking

2009-06-15T19:58:00.002+10:00

Imagery for diagrams by T. Dreyfus
in
Exploiting mental imagery with computers in mathematics education
By Rosamund Sutherland, John Mason

What attracted me to this article is the analysis of thinking visually or visual mental images, the article has a wider scope. A synopsis of the comments on visual mental images follows:

One cannot think without mental images
A subset of mental images is visual images: mental images with a strong visual component
They can be diagrammatic, 2 or possibly 3 dimensional, static or dynamic, definite or vague
One can watch processes in an evolving visual mental image. Watching the mental images can be more useful than watching real world objects.
It is difficult to analyse others' visual images as we have no direct access to them.
A mental image cannot be measured without being disturbed, (parallels with quantum mechanics), visual images are vague or fuzzy, in communicating an image to others, one needs to make it precise, changing it.
Images can be used for hypothetical reasoning or thought experiments though there are difficulties in retaining an image long enough to transform it and reason with it.
Are visual images pictures, or interpretations of diagrams?
Is diagrammatic information stored analogically or propositionally?
the analogically school believes it is stored like vision
the propositional school holds that interpretations of the visual information are stored
Experiments indicate that the images are interpreted abstractions rather than picture like encodings.
Physical drawings allow chunking, organisation of knowledge into perceptual chunks, do images?
Visual images are probably better at expressing underlying structure than other mental representations.

Problem visualisation in mathematics and programming

2009-05-21T20:31:00.003+10:00

I have been researching into problem visualisation in mathematics and programming following a discussion, originally by Mark Guzdial and continued by Bill Kerr Alan Kay and others and also the parallel discussion by Rob Costello

One paper that has me thinking is the influence of texts' mental images upon problems' resolutions by Giorgio Bagni (2000). It examines the importance of the level of detail of the mental models constructed by students. Bagni asks whether imagining a situation in all its details helps problem solving. Bagni suggests that it can be an obstacle.

Problems were given to 3 Italian school classes, (13-14 years), (14-15 years) and (15-16years).

The first version was briefly stated as an abstract mathematical problem:

The length of the basis AB of an isosceles triangle ABN is 1 000 000 m; the sum of its sides AN, BN is 1 000 001 m; find the length of the height NM.

The second version was embedded in a real world context and included a diagram:

Let us tie a row to two nails very far, say… 1000 km; let us imagine to use a row whose length is exactly 1000 km: so this row will be tight. Then let us tie to the same nails another row, whose length is 1000 km and 1 m; so this second row is a bit longer than the distance between the nails and it will not be tight: in order to stretch it, let us bring the second row in its middle point and let us “raise” such point (see the picture), in order to take it away from the first row, until the second row is completely tight.

a diagram was shown followed by more text

Well, how much must we take away the middle point of the second row? Find the distance between the middle point of the first row, M, and the middle point of the second row, N.

I am hoping that the second version has suffered in the translation from the original Italian to English because it does not read well in English.

Finally the students were shown the correct solution by Pythagoras' theorem which has the result, which may be surprising at first, that by allowing a 1 metre increase in total path length, it is possible to deviate sideways by over 700 metres.

The students in the first group, those given the abstract problem, did significantly better than the second group with the real world problem.

When shown the correct solution, many in the second group, the group that had the problem given in a real world context, had difficulty accepting the correctness of the solution because it was counter intuitive that a such a small increase in total path length would allow such a disproportionately large sideways displacement.

Bagni concludes: “that D’Amore (1997) clearly proved that the full possibility to imagine a situation does not help pupils; now we state that, sometimes, this full possibility can constitute an obstacle to the resolution (or, as in the examined case, to the acceptation of the correct resolution)”.

I hear echoes of Cognitive Load Theory here. The idea that if you are teaching Pythagoras, you should remove any distractors from Pythagoras, so as to minimise the cognitive load on the learner. The learner can then focus their limited processing powers on the material which is to be learnt.

My thought is that the cognitive conflict created by the second problem is valuable for learning and that students should be given time to experience and resolve such cognitive conflict if they are to have more than a superficial understanding of a subject.

This particular cognitive conflict relates to deeper understanding of geometry and physics. It is closely related to the concepts that:

For small x, sin(x) = x.

Over a given distance, the tangent is very close to the circumference if the circle origin is remote.

At x=0, the derivative of sin(x) is maximum but the derivative of cos(x) is zero.

Why is it increasingly hard to pull a rope span, a catenary, the closer to straight it gets? Because your mechanical advantage tends to 1/infinity. Which group of students would you rather have specifying the support structure for electricity cables crossing a busy road?

Jonassen talks of schooling to create real world problem solvers. In school you know that you are doing Pythagoras this week so any problem you are given will be solved in a similar way. Real world problems are poorly specified and multi disciplinary, they require students to have engaged in messy problems.

Turtle Fileview

2009-03-21T17:37:00.007+11:00

A fileviewer for Turtle Art using the programmable Python brick

The Python brick code

def myblock(lc,x):
 text=lc.heap.pop(-1)
 if x==0:
   dialog = gtk.FileChooserDialog("Load...", None, \
                gtk.FILE_CHOOSER_ACTION_OPEN, \
               (gtk.STOCK_CANCEL, gtk.RESPONSE_CANCEL,gtk.STOCK_OPEN, gtk.RESPONSE_OK))    
   dialog.set_default_response(gtk.RESPONSE_OK)
   fname = None
   response = dialog.run()
   if response == gtk.RESPONSE_OK:   
   fname = dialog.get_filename()
   dialog.destroy()
   f = open(fname, "r")
   f.seek(0)
   text = f.read()
   f.close()
   text="".join([z for z in text if ord(z)>0])
lc.heap.append(text)
lc.heap.append(text[int(x*500):int((x+1)*500)])

The file selection dialog box

Output screen, viewing a py file

Turtle Oscilloscope

2009-03-15T17:06:00.013+11:00

For the experimental Turtle Art Portfolio V18 for the XO hardware, this program uses the programmable brick and sensor input . (As at V19 Turtle Art Portfolio, the 2 imports below are no longer required.) (As at V44 of Turtle Art, the programmable block is supported but sensor input still is not.)


# Oscilloscope
# Tony Forster, March 2009
#

from taturtle import *
from math import *
def myblock(lc,x):              # x is volts input
ox=lc.tw.turtle.xcor         #old x coordinate
oy=lc.tw.turtle.ycor         #old y coordinate
nx=ox + 1                    #new x coordinate
ny= x                        #new y coordinate
setxy(lc.tw.turtle, nx, ny)  #jump to new coord.
draw_line(lc.tw.turtle,ox,oy,nx,ny)
return

A better oscilloscope

XO - Electricity and magnetism

2009-03-14T16:07:00.007+11:00

Required
XO laptop
75mm (3 inch) nail
insulated copper wire
3.5 mm phono plug
refrigerator magnet

Method
Wrap 50 turns of insulated wire onto a nail and connect the two ends to a phono plug as shown (if it is a stereo plug, probably the red wire and the copper shield). Connect the phono plug to the microphone input.

Start the Measure activity, sound tab, time base, maximum vertical sensitivity, minimum sweep speed (as shown).

Wipe the sharp end rapidly over the back of the fridge magnet, try both directions.

Questions
Try a different number of turns of wire
Try moving the nail more slowly, what happens to the period, frequency and amplitude of the wave?
What is happening?
Why does it work better on one axis of the magnet? (hint rub 2 magnets together)

Data logging with the OLPC

2009-03-12T16:03:00.030+11:00

The OLPC XO can measure external inputs with its microphone jack

Specifications

Standard 3.5mm 2-pin switched mono microphone jack; selectable 2V DC bias; selectable sensor-input mode (DC or AC coupled); (1)

If using a stereo plug it is the red wire plus the earth.

It is protected at the input by a 5V zener diode and has a measurement range of 0.3V to 1.9V. The allowable input is -0.5V to 5V Inputs outside this range will cause excessive current and damage. (2) (3)

Addition of a 150k ohm series resistor would (I expect, no guarantee) give a reduced sensitivity in voltage mode (0-4V) but allow inputs to +- 100V without damage. Input impedance in resistance, volume and pitch modes is much lower but a 1k ohm series resistor should still allow inputs to +-12V.

Measure V20

Resistance mode

350 ohms to 10 k ohms (0.2V to 1.78V, open circuit is 2.2V) the volume slider on the sound tab has no effect on sensitivity, half scale is 1.1V or 2.8k ohm resistance

Voltage mode

DC coupled, 0.3V to 1.78V

there is still 0.6V bias at open circuit, input resistance =140k ohms

Sound

Selecting the sound tab which allows sensitivity and timebase adjustment applies 2.2V bias and has AC coupling. Sensitivity is adjustable from 1mV peak-peak full screen to 0.2V peak-peak full screen.

TurtleArt V32

(sensor input is disabled in V42, maybe this stuff is irrelevant)

Resistance

Measuring resistance with Turtle Art

299 = 16 k ohms (maximum)

150 = 3.2 k ohms

0.2= 350 ohms (minimum)

The bias voltage is only applied briefly, approximately 140 mS, any circuitry would need to stabilise in this time. The cycle repeats quite quickly in the above program.

Bias voltage, reading resistance in Turtle Art

Voltage

When doing forever print voltage, open circuit gives a reading of 221. The bias is still applied but the cycle time is much slower, 500 mS for a program cycle

The voltage readings are inconsistent, when applying 0.3 V at the input ( from a source impedance of 30 K ohms), the output jumps between zero and full scale. Maybe its too sensitive, reading millivolts with a 0.3V deadband?

Pitch

Forever print pitch is broken, error: global name real fft is not defined

Volume

With the internal microphone, forever print volume gives an unstable reading, 30-200. Forever print volume wait 1 gives a background level of round 30

External input shown below, 1 kHz square wave applied through 4 uF and 100 k ohms, reads 30 for low inputs but jumps to 200 for a 2V p-p square wave in the unbiased state, note that for the period bias is applied, the early period, the input impedance is lower and the square wave has a smaller amplitude.

Forever print volume wait 1, screen size 0-3V height and 200 mS width, for the earlier part bias is applied, initial pulses of bias as in previous shot are just visible

Turtle Art Experimental V18V19

forever print pitch fails on the 8th loop, error audiograb.py line 65 unpack requires a string length of n. This is a buffer underrun issue and does not occur for manually repeated print pitch. Specifically, unpack() is failing if the buffer from alsaaudio has an odd number of bytes. In the trace below, odd length buffers were hacked to return zero. Doesn't seem to be doing anything sensible.

pitch for a 30 mV 1 kHz square wave, Turtle Oscilloscope

forever print resistance 500 ohms to 15 k ohms but unstable at zero ohms, alternating between 0.2 and 150 . Again, the 150's are caused by undersize buffers, this time even length.

forever print voltage 299 for 0V and 1.9V, 0.2 for 1.2V

This can be fixed by replacing the code in audiograb.py at line 87

   elif self.sensor_type==3:
sensor_val1 = (audioop.avg(buf, 2)*0.00152333) + 50.0

Giving a range of 0.4V to 1.9V for 0-299 but similarly to resistance returns occasional 150's for zero volts input. Again, the 150's are caused by undersize buffers, this time even length.

Turtle Oscilloscope, 0V input, values of 0 occasionally returned by audioop.avg, which after scaling (x+50)*3 =150

At line 358

changing set_capture_gain() seems to have little effect on mode 3 (voltage)but
changing set_mic_boost() gives a range of 1.06V-1.2V in mode 3 (voltage).

forever print volume 299 is 40 mV p-p, occasionally gives 0 or large negative number. Again, the errors are caused by undersize buffers, -ve for buffer length =1.

Volume, Turtle oscilloscope, 30 mV 1 kHz square wave, note spikes to zero

Notes

(1) http://wiki.laptop.org/go/Hardware_specification

Microphone input: standard 3.5mm 2-pin switched mono microphone jack; selectable 2V DC bias; selectable sensor-input mode (DC or AC coupled); (1)

(2) http://wiki.laptop.org/go/Talk:Measure

"What is the maximum voltage I can put into the mic/input port on the XO without risking damaging it?

Short answer -- 0.3V to 0.9V . ... -- there is a 5V reverse biased Zener diode at the input that protects the input ...

My measurements (I used a current-limited adjustable voltage supply) indicate no more than -0.5 volts to +5.0 volts. Beyond these voltages my audio input port drew large, potentially-destructive currents. This voltage is measured relative to the "chassis common" (the outer "shell" of the audio plug). Therefore: even a little AA 1.5 volt battery improperly applied (i.e. "backwards") may damage the laptop.

The Analog Devices AD1888 sound chip has the ability to sample DC voltages. Experimentally it has been found out that the range is fairly linear, however the range that it can sample is restricted to 0.3V - 1.9V, with all the internal gains turned to the minimum."

(3) http://wiki.laptop.org/go/Measure/Hardware

"The XO hardware has been designed to facilitate measurement of DC voltages by the addition of an electronic switch that can be controlled via a setting on the Alsamixer called 'Analog Input' . The high-pass filter can also be turned on/off by a setting 'High Pass Filter' in Alsamixer. The ability to control V_REFOUT (bias voltage) is also available and is done by the control 'V_REFOUT' in Alsamixer.

Measured between the center conductor and the shield (ground, i.e. +0 volts). When an input voltage is greater than +5.0 volts or less than -0.5 volts the input-protection circuitry draws currents greater than 100 milliamperes and will damage the laptop. Also, the AD1888 codec's absolute maximum voltage (given a 5.0 volts supply) is -0.3 volts to +6.3 volts.

You must use input protection resistors and voltage divider if voltages greater than +5 volts will be applied. Resistors and a fast-blow fuse are recommended. Resistors should be present in both the ground circuit and the signal circuit, and this may introduce noise. A better circuit is a high-impedance differential-input amplifier."

(4) http://www.jgc.org/blog/2008/03/building-temperature-probe-for-olpc-xo.html

John Graham-Cumming:Building a temperature probe for the OLPC XO-1 laptop

(5) http://www.olpcnews.com/software/applications/oscilloscope_children_learning.html

An XO Oscilloscope to Measure Children's OLPC Learning, One Laptop Per Child News

One Player Pong for TurtleArt

2009-03-08T22:05:00.004+11:00

For the experimental fork of TurtleArt V18

Move the bat with the A and D keys
Issues:
Slow execution speed
Running out of canvas for the blocks

Orbital motion in Python and TurtleArt

2009-03-05T15:21:00.018+11:00

Orbital motion according to Newton's law of gravity using the programmable block in the experimental fork of TurtleArt for the OLPC. (Now included in Turtle Art from V44)

Intended to demonstrate two things,
a) that programmable simulations are good ways for kids to learn physics and maths
b) that the programmable block provides a way for kids to move from simple drag and drop programming to more complicated text based programming

As at V18 of experimental TurtleArt, Rainbow is preventing the loading of the file tamyblock.py from the journal. See previous post. The following hack gets round the problem.

Open Terminal,
go to /home/olpc/Activities/TurtleArtPortfolio.activity
Save your edited tamyblock.py in the Journal immediately before typing

copy-from-journal tamyblock.py
mv tamyblock..py tamyblock.py

(as at v19 this is not required, neither are the 2 imports)


# Orbital motion with inverse square law
# Tony Forster, March 2009
#
# For each iteration, acceleration is calculated
# as inversely proportional to orbital distance.
# The horizontal and vertical components of the
# acceleration are added to the horizontal and
# vertical components of the velocity.
# The horizontal and vertical velocity components are
# added to the x and y coordinates.
# A line is drawn from the old to the new coordinates.
# The turtle is moved.

from taturtle import *
from math import *
def myblock(lc,x):                  # x is not used
hspeed=lc.heap.pop(-1)             # pop hor speed from the heap
vspeed=lc.heap.pop(-1)             # pop ver speed from the heap
point_distance2=lc.tw.turtle.xcor*lc.tw.turtle.xcor+
lc.tw.turtle.ycor*lc.tw.turtle.ycor
point_distance=sqrt(point_distance2)
hspeed -= lc.tw.turtle.xcor*800/(point_distance2*point_distance)
vspeed -= lc.tw.turtle.ycor*800/(point_distance2*point_distance)
ox=lc.tw.turtle.xcor                 #old x coordinate
oy=lc.tw.turtle.ycor                 #old y coordinate
nx=ox + hspeed                       #new x coordinate
ny=oy + vspeed                       #new y coordinate
setlayer(lc.tw.turtle.spr,630)       #make turtle visible
setxy(lc.tw.turtle, nx, ny)          #jump to new coord.
draw_line(lc.tw.turtle,ox,oy,nx,ny)
lc.heap.append(vspeed)               #push vert speed onto heap
lc.heap.append(hspeed)               #push hor speed onto heap
return

What was difficult:
Any syntax error in tamyblock.py will prevent TurtleArt from loading.
The Rainbow problem makes it more complicated, also copy-from-journal is unreliable and poorly documented, I obviously do not understand the syntax.
The error log shows where your error was in the source listing but if you haven't reloaded TurtleArt, you can be running one version of the code and seeing errors in a different version.
The TurtleArt wait block is necessary to see the turtle but it slows execution too much, it could be shortened, i used a hack setlayer setlayer(lc.tw.turtle.spr,630) but don't fully understand.

Browse activity on the OLPC

2009-03-04T09:40:00.007+11:00

In the spirit of "eat your own dogfood" I am trying to do as much as possible on my XO laptop. A laptop for children's learning should be "low entry, high ceiling and wide walls". That is, while providing an easy entry into computing, it should not have roadblocks to more complex tasks or uses which the designer never considered.

Here is today's roadblock on filling in a web form. Here is what I saw on a PC with Firefox 3.0.6
And on an XO with Browse V98, when selecting, no scroll bars:
And after moving to the next item, the selection unselects:
I am not sure if Browse supports JavaScript at all.

Here is part of the offending code, (html brackets changed to {})

{link rel="stylesheet" href="../fso.css"}
{style type="text/css"}
{!--
td {font-family: Arial, Helvetica, sans-serif ; font-size: 10pt; color: #090707}
--}
{/style}
{script language="JavaScript"}

...
{tr}
{td colspan="1"}
{select name="Q136383" SIZE="3" }
{option}Yes{/option}
{option}No{/option}
{option}Not applicable{/option}
{/select}
{/td}
{/tr}

OLPC language localisation

2009-03-02T20:14:00.012+11:00

image from http://wiki.laptop.org/go/Image:P1020317-1.JPG

One of the strengths of the OLPC is its philosophy of the child being "not just a passive consumer of knowledge, but an active participant in a learning community" and so the software was designed with "no inherent external dependency in being able to localize software into their language".

Language localisation of software
It seems that language localisation of the software would be a good learning project for children, it would give them a relevant and authentic project which I would expect to be highly motivating. I would expect it to be quite challenging for them and require a deep understanding of language and of the subject that the language was describing.

I found the Wiki of the Bering Strait School District inspiring with wiki dictionaries of the Inupiaq and Yupik languages which could be edited by teachers and students. Students could use a similar process to localise the OLPC software into their own language.

Localising Speak text to speech
An activity which the students apparently enjoy is Speak , a text to speech synthesiser. I tried to reproduce the process of editing the language dictionary described in the instructions on laptop.org and to provide more detail so that students could follow the instructions and localise Speak for their language.

I found the process quite difficult, largely due to the file management provided by the Journal. You can find the steps I followed here.

What was difficult:
Zip files can only be unzipped by Etoys
Etoys will not unzip to the Journal
Etoys has limited file privileges, I ended up unzipping to a temporary file in an obscure location
Transferring to the Journal requires Linux directory navigation and understanding of Mime
I was unable to transfer from the Journal to the target directory because of root user issues
The Journal added a .txt extension that had to be removed
copy to and from journal are poorly documented and complex

An operating system for children is ideally low entry, high ceiling and wide walls. That is it should be easy for children to start with, have a well graded pathway to very complex functions and it should allow children to do anything, including things that we could never anticipate.

I am trying to get to like the Journal and Browse but its not easy.

Thank you Elvis

2009-02-24T09:50:00.004+11:00

"Elvis" returns to pick up more water

A big thank you to the CFA and the fire bomber "Elvis". I was watchful but not particularly concerned yesterday, 4 km downwind from the Upwey bushfires, under the smoke plume, the light had turned that orange colour. Then there was a second column of smoke and much closer, 200 metres from the house. Was it a spot fire? There had been no sign of embers or ash falling from the sky.

Then "Elvis" the big helicopter arrived dumping 10 tonnes of water at a time. It dumped 5 or so loads, passing directly over the house at treetop height till the fire was out, or at least manageable by ground crews.

Today, no sign of smoke, just burnt trees

Using Python blocks in TurtleArt

2009-02-12T14:42:00.015+11:00

The Python block and file tamyblock.py
There is the facility to insert a block of Python code into TurtleArt in its current experimental fork, TurtleArtPortfolio on the OLPC. (This feature is now in Turtle Art from V44) Thanks Walter for the following help.

As of TurtleArtPortfolio V17 , when TA is first run, it creates a copy of tamyblock.py in the journal.

This code can be opened with Pippy and edited. There are some example blocks of code there which are commented out with #

The Python code can be loaded into TA using the Save/Load menu tab.

Replacing a deleted tamyblock.py
If you delete tamyblock.py from the journal, you need to manually replace it (this may change with later versions). In terminal go to directory
//home/olpc/Activities/TurtleArtPortfolio.activity
and use the copy-to-journal command, note you need to supply the MIME (see also) type for the file, text/x-python:

copy-to-journal tamyblock.py -m text/x-python

Error messages
Errors executing the code and the output of any print statements are directed to the (TAPortfolioActivity ??) log file The log files are at ~/.sugar/default/logs and can be viewed with the Log activity

Rainbow security
Currently having problems with Rainbow security settings, follow this link to Rainbow for how to disable it.

Version 19 update
Rainbow problem circumvented V19. tamyblock not required, cannot do imports

Turtle Lander

2009-02-09T08:57:00.010+11:00

For TurtleArt in its current experimental fork, TurtleArtPortfolio on the OLPC. Use the a s d keys to fire the thrusters. Keys do not auto-repeat.

Issues
Execution speed is becoming an issue, each block adds 2-5 mS, the print adds 25mS, the wait 1, which is necessary to see the turtle, adds 10mS.
The area of the canvas limits how big a program you can create, is it worth adding scroll bars?
Dragging the stack of blocks is starting to become slow.
It is not possible to test if a key is held down.

Timing program execution
I used the following TA program to time the execution time of each block. It uses the clock() Python function from the time library.

block milliseconds
nothing** 0.21ms
clean 20*
forward 0 3.37
left 0 2.5
arc 0 0 4.99
setxy 0 0 3.35
seth 0 2.3
store in box1 xcor 1.49
text 16 5.23
pen down 0.82
set pen size 0 1.27
set color 0 1.47
set text color 0 1.42
fill screen 0 0 20*
store in box1 pensize 1.5
store in box1 0+0 2.36
store in box1 1/1 2.33
store in box1 random 0 100 3.09
query kyb 1.0
store in box 1 keyboard 1.56
store in box 1 x x=1 2.85
store in box 1 volume 7*
repeat 1 2.02
if 1=1 3.74
hor or vert spacers 0.8
variable = 1 1.61
push 0 1.23
store in box1 pop 1.6
show heap 23
empty heap 0.9
hide blocks 300

*timer unreliable
**timer overhead-subtract from others

Using the insert function block in TurtleArt

2009-02-07T15:26:00.012+11:00

TurtleArt in its current experimental fork, TurtleArtPortfolio , allows students to use Python functions in a special block.
The intention of this feature is to provide a "higher ceiling" for open ended learning. I decided to try this function to do an analogue clock , a task that I had previously done in Gamemaker.

It turned out to be a trivial exercise for some learning goals because trigonometric functions of sin() cos() and pi() were not required, I could just use set heading.

I required the time library functions from Python which had not been imported, this meant I had to hack the TurtleArt source file talogo.py adding the line

from time import localtime

(as of V13, this is not required)

The programmming in TA visual blocks is shown in the picture below.

The code to the right draws 12 hour marks from radius 200 to 220. The code to the left draws the second, minute and hour hand. The heading for the second hand, for example, is calculated as

seth=localtime().tm_sec * 6

for the minute and hour use tm_min and tm_hour respectively.

The output:
What I found hard
The time function that I required was not already imported into TurtleArt. Can you use the insert function block to import a library? Apparently not because import does not return a value. Could the block be reprogrammed so that it does not need to return a value? If all likely imports are already programmed in, does TurtleArt become clumsy, slow to load and a memory hog? If students can't access all functions they don't have a sufficiently high ceiling.

Finding the correct syntax for time . There was a lack of documentation or programming examples that explained that localtime() returns a structure with elements including tm_hour. Also the correct syntax depending on whether one function or the whole library was imported. Specifically, it was hard to discover that the correct syntax could be:

import time
mytime=time.localtime()
myhour=mytime.tm_hour

from time import localtime
mytime=localtime()
myhour=mytime.tm_hour

and that the two lines of code above could be combined, eliminating the need for the temporary structure variable mytime

from time import localtime
myhour=localtime().tm_hour

It either needs better documentation, more code examples or both.

What didn't work
The block has insufficient space to type in long expressions, you can't edit an expression, you have to retype it, when dragging a block containing a long expression, it leaves bits of text on the canvas.

Reprogramming Sugar

2009-01-28T10:19:00.008+11:00

One of the core ideas of the OLPC was that the underlying programming be visible to kids.

"the View Source button allows one to look behind the activity, peeling away layers of abstraction in order to reveal the underlying codebase which makes it tick. This feature will integrate cleanly with the Develop activity, encouraging children to view, modify, and redistribute variations on the activities they use. Through collaboration and sharing, a garden of home grown activities will begin to develop on the laptops, created by the children themselves."

OLPC Human Interface Guidelines

Pressing function space is meant to show the code. I recently looked to see how many of a selection of activities supported view code

activity .........Shows source
write ..................no
calculate ............no
ruler ...................no
speak ..................no
turtleart .............no
chat .....................yes
pippy ...................yes
record .................no
etoys ...................no
browse ................does not reveal application code, saves the webpage, can paste to write to view html but not intuitive

Hopefully more activities will have this feature enabled.

I was inspired by Walter Bender's Patching Turtle Art to see how easy it was for casual programmers like myself to patch activities. With some help from Walter, I have documented the process at Modifying_Activities . I show there examples of hacking activities, I hope that it will give teachers and more importantly students the confidence to try.

I did not find it easy , you will see that my efforts are mainly about changing constants and variables, not changing program flow. Here are my thoughts on what was hard:

locating the source code for applications
finding suitable programming tools
lack of documentation
understanding Linux
understanding Python
library documentation
object oriented programming
undestanding how program code is integrated with Sugar
no high level programming tools

A lot of the problem is about encapsulation and high level tools. Back in DOS days, it was relatively easy for the casual programmer to create applications. Just type print("hello world") into the IDE, press build and you had made your first application. Then Windows and C++ arrived and hello world took pages of code, only for the professionals. Fortunately VB came along, and despite its shortcoming, hello world was possible again for the casual programmer.

We do not think about print() but it represents pages of assembly code which has been encapsulated into a single command. Likewise, VB encapsulated pages of window handles and messaging into the simple action of dragging a button onto a form.

This allows the learner to do solve different problems, ones that are more appropriate to their learning trajectory. There is a lot of value in allowing students to become good problem solvers and good self directed learners but this is unlikely to happen if some programming issues aren't solved and encapsulated for them.

The messy business of creating an application has to be encapsulated if students are going to create applications. This could be by providing a high level programming environment which automates the messy stuff. It could be through providing a template or blank application in the distribution and appropriate documentation.

2008-10-25T10:33:00.001+11:00

Just testing Justin TV which gives free TV broadcasts.

It was used for the Waveplace awards today. The panel below should show a live TV feed if I broadcast.

Watch live video from tonyforster's channel on Justin.tv

Educational Use of the Wii remote

2008-10-22T07:14:00.000+11:00

The Nintendo Wii videogame has a handheld controller, the Wii Remote. The Wii Remote has the ability to sense acceleration along three axes through the use of an ADXL330 accelerometer. It also contains a 1024x768 infrared camera with built-in hardware blob tracking of up to 4 points at 100Hz. The Wii Remote communicates wirelessly with the console via short-range Bluetooth radio.

Johnny Chung Lee has Demonstrated how the infrared camera can be used for third party applications including an interactive whiteboard at http://www.cs.cmu.edu/~johnny/projects/wii/ Another third party project, GlovePIE by Carl Kenner allows the Wii Remote to be used on a personal computer to emulate a keyboard, mouse or joystick. http://carl.kenner.googlepages.com/glovepie

Hardware
A IR LED light source is required. The LED chosen is the CAT. NO. ZD1945 from Jaycar Electronics

It has the following specifications:
Forward Current (If): 50mA max - Peak forward current (Ip): 1.2A- Forward Voltage (VF): 1.2V @ 20mA - Reverse Voltage (VR): 5V max- Power Dissipation (Pd): 100mW max - Viewing Angle: 30°- Peak Spectral Wavelength(IR): 940nm @ 20mA * Spectral Bandwidth (DI): 50nm@20mA- Material: GaAs

It was chosen to run it conservatively at 14 mA with a 1.5V battery and 22 ohm series resistor.
(1.5V -1.2V)/22 = 14mA

The longer LED lead connects to the battery + , the resistor is in series.

The IR source can be easily tested because webcams and digital cameras can receive the IR spectrum as the following photo shows:

Low-Cost Multi-point Interactive Whiteboard Software
Johnny recommends BlueSoleil, a third-party driver that implements the full Bluetooth stack for various Windows operating systems. You can download a trial version that has a 5MB transfer limit at http://www.wiili.org/index.php/BlueSoleil

This driver was not required (running a Dell Inspiron 1520 with Vista), the Windows driver accessed through Control Panel was sufficient. Open control panel and click on the Bluetooth icon

While pressing the A&B buttons on the Wii Remote, click on add.

Select the Wiimote when it appears and select no passkey.

Download the whiteboard software from http://www.cs.cmu.edu/~johnny/projects/wii/

Run the whiteboard executable WiimoteWhiteboard v0.2.exe , if you have alrerady established Bluetooth communucation with the Wii it should load:

Clicking on Calibrate Location brings up the 4 calibrate points, flash the IR LED at the four calibrate points.

Tracking Your Fingers with the Wiimote
http://www.cs.cmu.edu/~johnny/projects/wii/WiiMultipointGrid.zip should run without the directx SDK but gave the following error “Directx SDK sample has stopped working.”

GlovePIE
Blue Soleil was not required. Just download the GlovePIE zip from and run GlovePIE.exe
You can setup the Bluetooth from within GlovePie by choosing the Control Panel-Settings > Bluetooth menu in GlovePIE. You should then select Bluetooth Fix from the Troubleshooter menu.

press add and hold down the 1+2 buttons on the Wiimote, tell your Bluetooth program to search for devices,

I chose no passkey.
Generate an appropriate script, either by typing into the left script tab or by selecting options from the GUI tab.

For example, the following script gives control over a dummy mouse pointer and can easily be generated using GUI tab options.
Cursor0.x = MapRange(Wiimote1.Roll, -90 degrees,90 degrees, 0,1)
Cursor0.y = MapRange(Wiimote1.Pitch, -90 degrees,90 degrees, 0,1)

Quest Atlantis

2008-10-22T07:07:00.000+11:00

Which Programming Language Makes it Easier for Students to Learn to Program?

2008-10-03T11:50:00.000+10:00

In an interesting presentation at ACEC2008, Jason Zagami presents the results of a study, Which Programming Language Makes it Easier for Students to Learn to Program?

Jason tests text only languages, PHP and VB, mixed text/graphics languages Game Maker and Alice and a graphics only language Robolab (Labview) .

The languages were tested in an Australian girls' secondary school. The difficulty reaching levels of competency in programming language structures such as simple sequencing and nested loops was compared.

"programming languages that rely predominantly on visual representations were shown to be more effective in supporting student understanding of introductory programming concepts than programming languages relying predominately on text"

If I understood his presentation, he further indicated that mixed text/graphics languages were better for simple concepts like sequencing but text only or graphics only was better for more difficult concepts like nested loops.

I look forward to reading the wider study when it is published: Zagami, J. (2008). Seeing is understanding: The effect of visualisation in understanding programming concepts. (Doctoral dissertation, Queensland University of Technology, 2008). Dissertation.

2008-09-04T06:45:00.000+10:00

Bioware, creators of Neverwinter Nights have announced the Dragon Age™ Toolset. It looks like it will allow students to create computer games similarly to Neverwinter Nights.

The following quoted from their web site :

Create Original Adventures – Using the rich set of Dragon Age assets and locations as starting blocks, users can modify these stunning areas by adding new quests, characters and scripting to craft their own adventures, fate–defining conversations and cut–scenes.
Powerful Script Editor – Users can fully customize combat and creature AI, allowing them to create detailed action sequences full of heart-pounding party–based tactical combat.
Content Creators Community – BioWare plans to have a dedicated community area online where content creators can share content easily and get content updates for the toolset.
On–Going Toolset Content Updates – BioWare plans to release additional assets and features for the toolset in the future, allowing for expanded creation of new areas.

BioWare has a long history of delivering powerful content–creation toolsand support to its community. In 2002, the studio released a Toolkit for the ever popular Neverwinter Nights™ which has allowed fans to create over 5,000 adventure modules of their own design, the most fan-created content in BioWare's history. Fans have not only created stand-alone adventures with the trailblazing Neverwinter Nights toolset, they still continue to create modules, five years after its original release and have crafted thousands of completely new monsters, hundreds of thousands of in–game objects (eg. weapons, armor, food, special effects, building facades, etc.) and dozens of worlds.

For more information about Dragon Age™: Origins, the latest updates, or to join BioWare's Dragon Age community, visit www.dragonage.com