ILXO/projects

Summer Wrap-Up

Completed

Jams

• Teacher Jam Chicago
• Game Jam Chicago

Workshops

• ILXO Workshops
  • Tried some online, making use of Ustream.tv, DotSub. (write-up thoughts on this as a communications medium?)
  • (super mini music one)
  • Record-focused demo/workshop at MVCC in Blue Island - Blog
  • Using XOs with a roller-coaster building activity at the MSI - Blog

Demos

• ILXO Jr. Meetup at Naperville Library
  • Post by Mel
  • Post by Melanie

Repairs

• Disassembly and VIDEOS (link)
• Exploded XO

Multi-XO mesh testbed

(need instructions - go Mel!)

Almost done

School Chapters

There's a mailing list, yay!

Voltage regulator

Circuit diagram

This section provides an overview on a current and voltage regulator peripheral for the XO. Though a wide variety of power generator options are possible for powering the XO, the incoming power must be regulated to avoid shorting the laptop. The XO accepts an input voltage potential of 11V to 25V. If you go below this range, the recharge circuitry won’t kick in and if you go above the 25V the internal fuse on the laptop power circuit will short. The laptop can also not accept an input current of more than 2A so regulating the current is also usually necessary for powering the laptop. This regulator is intended to act as a peripheral that can be plugged into the XO power plug and modify the input voltage and current from a power generator so that it can be used to charge the XO without harming the internal circuitry. The regulator has only been partially tested, so any further development or feedback is strongly encouraged.

The regulator consists of a full bridge rectifier attached to a voltage and current regulatory circuit using an inexpensive L200 voltage regulator. Since the XO can’t charge at more that 17W, the regulator will output either 12V at 1.5A or 18V at 1A based on the resistors used in the circuit. A table of selector resistor values for producing the desired output along with governing equations is provided below.

Vout	Iout	R1	R2	R3	C1	C2
12V	1.5A	1K Ohms	3.3K Ohms	0.3 Ohms	10x10^-6 F	0.1x10^-6 F
18V	1A	1K Ohms	5.5K Ohms	0.45 Ohms	10x10^-6 F	0.1x10^-6 F

Iout(max) = 0.45V/R3

Vout = Vref(1+R2/R1) where Vref = 2.77V

The L200 circuitry is based off of a circuit used by Arjun Sarwal and Richard Smith for regulating a cow power generator in India (L200 design guide). This IC and circuit is desirable for it’s low cost and minimal use of components, while being able to accept an input voltage as high as 36V (or a 60V peak for 10ms). As this regulator only outputs 18W, a battery connected to a zener diode would divert excess power from the voltage input to a battery. It's not clear what voltages and currents the battery would encounter, so it's recommended that some additional regulatory circuitry be added to regulate power to the battery to an acceptable level. If an XO battery is used as a backup battery, the voltage should be between 5V and 7.3V and the current should never exceed 3.15A. If you decide to include a backup battery in the circuit, please be careful when charging the battery by ensuring that you're using the proper battery charging circuit as they can be very unstable when not charged properly.

Postponed

Chording Keyboard

Not intended to finish as ILXO this summer, but work will continue on through the school year

Remaining To-Do

• ILXO: the aftermath write-up

• Figure out to do with blank t-shirts
• Follow-up on...
  • Local volunteers
  • MSI
• XO allocation
  • How many, to where?
• Inventory

Nixed

• XS test bed
• Library XO lab
• Library mentorship program

Original Plans

Grassroots experimentation

What effects do various things - spaces/locations, people, projects, structures, procedures, events - have on the running of a grassroots group? When we make guesses, we're documenting them in the form of hypotheses and following through the course of the scientific method to find the result, with the intent of capturing these experiences in a way that's useful to other grassroots groups. This isn't particular to the ILXO office, by the way; we welcome and encourage other grassroots groups that want to do the same. (more...)

Power peripherals

This project explores different possibilities for off-the-grid power charging peripherals for the XO. This includes evaluating the performance, lifecycle, human factors issues and feasibility of existing power options for the XO and expanding this list to include other existing peripherals. Chris is also working on the development of new power generating peripherals, particularly focusing on using appropriate technologies to allow users to develop simple power generating systems from scratch with minimal need for imported components. Results from this summer will be compiled into a “power generation” guide to help both XO users and developers learn from these findings and continue to help develop new power systems for the XO or for other applications. (more...)

XO Accessibility

How can the XO be used by children with various learning and physical disabilities as a tool that they build themselves in order to differently interact with the learning environment that surrounds them? This research project will explore the usability of the XO and its various activities and modes from the perspectives of various types of "differently-abled" users. We will also be creating inventions and adaptations to make the set of core activities more usable by children with special needs. (more...)

Miniprojects

Language learning through RPGs

Melanie Kim is building an RPG for learning foreign languages (using Spanish as the test case). The game will involve sending the player on "Quests". For example, if there were a quest for the player to search for objects for a birthday party, they could search for typical objects found at a birthday party (balloons, cake, lights, etc.) while learning the names of these objects in Spanish.

Environmental impact of XOs

Mia Kato is exploring the environmental impact XO usage at an individual school has (how much more power is consumed? how much energy goes into making one laptop? how much more waste is produced due to broken laptop parts, etc?) and coming up with ways to minimize this impact and educate pilot schools about it.

Science kits in a box

Prototyping and packaging "lab kits" with curricular materials and devices to teach chemistry, physics, optics, etc. so that teachers can buy or create prepackaged "activity boxes" to go through with their students.

Everything is a sensor input

Not all the sensor inputs to the XO are easily accessible via high-level software. For instance, getting power/charging data from the power-in plug port is currently a nontrivial process; it's also unclear whether data from the hall effect sensors mounted on either side of the screen is available, and so forth. The challenge here is exposing all these sensor inputs to a Python library that can easily be loaded and used in other applications.