OLPC India/Khairat Technical: Difference between revisions
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[[Khairat school|Khairat school]], [[OLPC India|OLPC India]] |
[[Khairat school|Khairat school]], [[OLPC India|OLPC India]] |
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[[image:P1070778.JPG|thumb|400px|[[Media:P1070778.JPG|actual size]]|XOs at Khairat getting charged (Picture by [[User:Carla|Carla]])]] |
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'''Work on this document is in progress''' |
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=Credits= |
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# All photos are by [[User:Carla|Carla]] unless otherwise mentioned. |
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# Most of the textual matter is by [[User:Arjs|Arjun]] |
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[[Image:P1060245.JPG|thumb|center|250px|XOs at Khairat school]] |
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=Deployment of Laptops in general - reaction, expectations and feelings= |
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==Comments== |
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The kids love their XOs and remain with them all day. The parents of the kids spend time with their kids and the XOs and have started to take an interest in learning about the various things their child learns from the XO. I observed that - |
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# All photos are by [[User:Carla|Carla]] unless otherwise stated. |
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* Most of the parents are familiar with the term 'Computer' and consider the XO to be a computer. However, since they have never worked on the computer, they |
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# The following are my views and may not necessarily reflect that of OLPC. For official clarifications on any of the technical aspects, please contact people at OLPC directly. |
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* The green color and the various visual design elements make the XO an attractive and easy to take to machine. For example the green color of the XO is a symbol of prosperity in India and in the [http://www.33ff.com/flags/XL_flags/India_flag.gif Indian Flag]. |
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* The parents are very keen to use the internet from the XO. Currently only one newspaper is distributed in the village which arrives late in the day as the village is far from the city. The parents are excited about reading many Marathi newspapers for free on the XO. |
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=School server - default setup and road ahead= |
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''picture of school server'' |
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==Hardware== |
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The school server machine is a P4 2.4Ghz machine with 512MB of RAM. |
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==Software== |
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==Deployment of Laptops in general - reaction, expectations and feelings== |
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==School server - default setup and road ahead== |
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==School server - power solutions== |
==School server - power solutions== |
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The power solutions for the school server would be different for alternative power solutions for charging the XOs. This is because the power consumption of the school server is more than the power consumption of the XOs. |
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==Providing internet in the remote village== |
==Providing internet in the remote village== |
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Currently a dialup internet connection through a fixed wireless phone that has been provided by Reliance Communications connects to the school server. See [http://www.rcom.co.in/webapp/Communications/rcom/Rh/rh_fwp.jsp here] for details about the connection provided. There is a plan to connect Khairat with a faster internet connection. However the remote location and a small number of users make it difficult to arrive on a quick solution. |
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==Localization, Keyboard and Fonts== |
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=Localization, Keyboard and Fonts= |
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== The Sugar experience == |
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The current XOs have English keyboards. However latest software builds also support rendering and display of Hindi, Marathi and various other Indian languages. |
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== Overview of observed Bugs== |
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===Power adapters and their alignment=== |
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===Touchpad=== |
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===The journal=== |
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Some XOs on the 613 images had their Journal gone. Image 616 fixed that bug. |
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Once the teacher lost his files. As a result an automatic backup script was written by Amit in the site. --[[User:Carla|Carla]] 16:56, 30 October 2007 (EDT) |
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== Scale and replicability of pilots and deployments== |
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== Alternative power == |
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The power supply in town is not very reliable, so many days we didn't have power, or had it intermittently. The children tried to bring their XOs charged, but still some needed to charge them at school. --[[User:Carla|Carla]] 16:56, 30 October 2007 (EDT) |
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A Devangari keyboard layout is in prototype stage. |
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===Cow Power Design Notes=== |
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[[Image:MR-MP-v2.png|thumb|center|600px|Devanagari Keyboard Layout]] |
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For the languages spoken in India, localization teams exist for |
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* Bengali |
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* Hindi |
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* Punjabi |
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* Malayalam |
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* Urdu |
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Bengali, Hindi and and Urdu teams seem to be quite active. There is also talk about the Pune center of Redhat [http://mm.ilug-bom.org.in/pipermail/linuxers/Week-of-Mon-20071231/062479.html being involved] in the Indic localization efforts. |
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Rendering is flawless for most activities, with high quality Free/Open Source Open Type fonts existing for most, if not all scripts. The Lohit set of Indic fonts, which come with Fedora have good coverage. |
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[[User:Sayamindu|Sayamindu]] |
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= Overview of observed Bugs= |
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==Alignment of power adapters== |
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The power strips available in India require the power adapters to be at 90 degrees to the current alignment. This issue has already been resolved as there are now two variants of power adapters being manufactured. |
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==Touchpad== |
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Kids were facing difficulty in having a good amount of control on the cursor using the touchpad. There are three attributes to this - |
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* Kids use more than one finger - sometimes 2 to 3 |
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* A variety of different conditions under which the keyboard is used - sometimes sweaty hands, hands with a little amount of mud etc. |
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* Jumpy mouse bugs - most of which as of today have been resolved. See |
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[http://dev.laptop.org/ticket/5799 5799] and [http://dev.laptop.org/ticket/4183 4183] |
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==The journal== |
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Some XOs on the 613 images had their Journal gone. Image 616 fixed that bug. Once the teacher lost his files. As a result an automatic backup script was written by Amit in the site. (Carla) Ticket [http://dev.laptop.org/ticket/3978 #3978] tracks this. As of today, this bug is fixed. |
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==Small text and buttons== |
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Some text and buttons are too small for the kids to be able to click easily. Ticket [http://dev.laptop.org/ticket/4070 #4070] tracks this. |
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= Alternative power solutions = |
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Electricity supply at the village is not reliable and in a day the power cuts can range from 4-20 hours. |
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Comment by Carla - |
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The power supply in town is not very reliable, so many days we didn't have power, or had it intermittently. The children tried to bring their XOs charged, but still some needed to charge them at school. |
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==Solar power== |
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We tested out a solar panel at the project site by taking current and voltage measurements. We got about 12V 400mA output in maximum sunlight intensity. This value changes if the orientation/slant of the solar panel is changed. The power obtained is thus about 4.8W which is close to the theoretical limit of 6W of the solar panel. This solar panel costs about $10. |
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==Cow power== |
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[[Image:P1070776.JPG|thumb|center|300px| |
[[Image:P1070776.JPG|thumb|center|300px|First prototype]] |
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==Mechanical design== |
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==Electrical design== |
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===Requirements=== |
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# Regulate current. The XOs at Khairat school have LiFePO4 type batteries. Let us chose a 1A charging current so that with the given capacity of the dynamo, we can charge about 15 XOs simultaneously. See [[Battery Charging]] for more details about all kinds of batteries that are used in the XO |
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# Regulate voltage. The XO power supply accepts voltage from 9V - 18V . The charging circuit switches on at 9.85V. Let us chose to fix the voltage that we give the XO at 12V |
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===Design approach=== |
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* Using L200 as the central component - it is cheap, easily available and most of all robust |
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* Referring to this [http://www.zen22142.zen.co.uk/Circuits/Power/l200.html sample circuit] and deriving parameters from this [http://bwir.de/download/L200_englisch.pdf design guide] |
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* To avoid effects of shorting or reversing of supply from dynamo to the L200 circuit a simple full wave bridge rectifier using 1N5408 diodes has been used. Also, a 100uF 35V decoupling capacitor is being used after the rectifier. |
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===Deriving circuit parameters=== |
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# For values of R2 and R1, I referred to table in right column of Page 4 of design guide. Selecting Vo=12V +-4% I get '''R1= 1K ohm +-1% and R2=3.3K +-1%''' |
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# Since Isc = 0.45/Rsc (according to sample circuit design), I chose '''Rsc=0.47 ohm 1/2 watt''' |
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# Current in R2, Ir2=(Vo-Vref)/R2 where Vref = 2.77V. Hence power dissipation in R2, Pr2 = '''25.8 mW''' |
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# Current in R1, Ir1=Vref/R1 = 2.77mA . Hence power dissipation in R1, Pr1 = '''7.7 mW''' |
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# Hence R1 and R2 can be chosen to be 0.25W type |
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We explored the development of alternative power solutions in the village. Our approach was to develop power solutions around locally available mechanisms. At the village (pilot site near Mumbai) we explored the ideas of using solar |
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power (in Mumbai sunlight is not consistently strong) , running water (we couldn't find any local water bodies nearby), wind power (no wind in the |
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that area), mounting small dynamos on bicycles (we found out that in that area bicycles aren't that common at all, esp in that village). But the |
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village had an abundance of cattle - that were being used in the fields. So we decided to design something around that. |
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===Acknowledgments=== |
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Thanks to Richard Smith for help in the electrical design. |
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Read details about the [[Cow_Power|Cow Power]] solution and updates [[Cow_Power|here]] |
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= Working with content creation groups= |
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--[[User:Arjs|Arjs]] 11:18, 16 November 2007 (EST) |
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==I want to develop content, how do I help?== |
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==Internet connectivity at pilot site== |
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For now, we are hosting learning resources here on the OLPC wiki. To get started, take a look at the [[Educational activity guidelines]]. Then, visit the page of [[sample learning activities]] to find a list of learning activities and templates in development. |
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== Wireless tests == |
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===Village topology=== |
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===Conditions=== |
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===Range and results=== |
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==Sharing Experience== |
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===In the classroom=== |
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Amit and I, together with the teacher and the children, did some testing on the Mesh by sharing activities. Children were working on the laptops and did different kinds of sharing to work with their classmates. The Sharing Activities wasn't that intuitive, we weren't really successful with it. Nevertheless, the children who shared activities were super-happy. --[[User:Carla|Carla]] 16:56, 30 October 2007 (EDT) |
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=Comment by Carla= |
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== Working with content creation groups== |
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I was very involved with the technical side with Amit, until Manu and Arjun arrived. I still was in the loop but more involved with the educational side. So, I'll focus on the aspects that had an impact on the educational side [[Khairat Chronicle]]. We worked with the developers daily to tackle these issues. |
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[[Category:OLPC India]] |
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==Comments== |
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I was very involved with the technical side with Amit, until Manu and Arjun arrived. I still was in the loop but more involved with the educational side. So, I'll focus on the aspects that had an impact on the educational side [[Khairat Chronicle]]. We worked with the developers daily to tackle these issues. --[[User:Carla|Carla]] 16:56, 30 October 2007 (EDT) |
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Latest revision as of 13:41, 9 November 2008
Credits
Deployment of Laptops in general - reaction, expectations and feelings
The kids love their XOs and remain with them all day. The parents of the kids spend time with their kids and the XOs and have started to take an interest in learning about the various things their child learns from the XO. I observed that -
- Most of the parents are familiar with the term 'Computer' and consider the XO to be a computer. However, since they have never worked on the computer, they
- The green color and the various visual design elements make the XO an attractive and easy to take to machine. For example the green color of the XO is a symbol of prosperity in India and in the Indian Flag.
- The parents are very keen to use the internet from the XO. Currently only one newspaper is distributed in the village which arrives late in the day as the village is far from the city. The parents are excited about reading many Marathi newspapers for free on the XO.
School server - default setup and road ahead
picture of school server
Hardware
The school server machine is a P4 2.4Ghz machine with 512MB of RAM.
Software
School server - power solutions
The power solutions for the school server would be different for alternative power solutions for charging the XOs. This is because the power consumption of the school server is more than the power consumption of the XOs.
Providing internet in the remote village
Currently a dialup internet connection through a fixed wireless phone that has been provided by Reliance Communications connects to the school server. See here for details about the connection provided. There is a plan to connect Khairat with a faster internet connection. However the remote location and a small number of users make it difficult to arrive on a quick solution.
Localization, Keyboard and Fonts
The current XOs have English keyboards. However latest software builds also support rendering and display of Hindi, Marathi and various other Indian languages.
A Devangari keyboard layout is in prototype stage.
For the languages spoken in India, localization teams exist for
- Bengali
- Hindi
- Punjabi
- Malayalam
- Urdu
Bengali, Hindi and and Urdu teams seem to be quite active. There is also talk about the Pune center of Redhat being involved in the Indic localization efforts. Rendering is flawless for most activities, with high quality Free/Open Source Open Type fonts existing for most, if not all scripts. The Lohit set of Indic fonts, which come with Fedora have good coverage. Sayamindu
Overview of observed Bugs
Alignment of power adapters
The power strips available in India require the power adapters to be at 90 degrees to the current alignment. This issue has already been resolved as there are now two variants of power adapters being manufactured.
Touchpad
Kids were facing difficulty in having a good amount of control on the cursor using the touchpad. There are three attributes to this -
- Kids use more than one finger - sometimes 2 to 3
- A variety of different conditions under which the keyboard is used - sometimes sweaty hands, hands with a little amount of mud etc.
- Jumpy mouse bugs - most of which as of today have been resolved. See
The journal
Some XOs on the 613 images had their Journal gone. Image 616 fixed that bug. Once the teacher lost his files. As a result an automatic backup script was written by Amit in the site. (Carla) Ticket #3978 tracks this. As of today, this bug is fixed.
Small text and buttons
Some text and buttons are too small for the kids to be able to click easily. Ticket #4070 tracks this.
Alternative power solutions
Electricity supply at the village is not reliable and in a day the power cuts can range from 4-20 hours.
Comment by Carla - The power supply in town is not very reliable, so many days we didn't have power, or had it intermittently. The children tried to bring their XOs charged, but still some needed to charge them at school.
Solar power
We tested out a solar panel at the project site by taking current and voltage measurements. We got about 12V 400mA output in maximum sunlight intensity. This value changes if the orientation/slant of the solar panel is changed. The power obtained is thus about 4.8W which is close to the theoretical limit of 6W of the solar panel. This solar panel costs about $10.
Cow power
We explored the development of alternative power solutions in the village. Our approach was to develop power solutions around locally available mechanisms. At the village (pilot site near Mumbai) we explored the ideas of using solar
power (in Mumbai sunlight is not consistently strong) , running water (we couldn't find any local water bodies nearby), wind power (no wind in the
that area), mounting small dynamos on bicycles (we found out that in that area bicycles aren't that common at all, esp in that village). But the
village had an abundance of cattle - that were being used in the fields. So we decided to design something around that.
Read details about the Cow Power solution and updates here
Working with content creation groups
I want to develop content, how do I help?
For now, we are hosting learning resources here on the OLPC wiki. To get started, take a look at the Educational activity guidelines. Then, visit the page of sample learning activities to find a list of learning activities and templates in development.
Comment by Carla
I was very involved with the technical side with Amit, until Manu and Arjun arrived. I still was in the loop but more involved with the educational side. So, I'll focus on the aspects that had an impact on the educational side Khairat Chronicle. We worked with the developers daily to tackle these issues.