This first post will hopefully be a staple for future people to work on the GPS-A-Sketch hardware platform. As technology changes and more people get involved, I expect the ideas that drive this project to change as well. Consider this a living document.

The idea behind the GPS-A-Sketch was to create an open shareable design that many users could use as the foundation for a modular, user-programmable, portable, GPS receiver. As the technology comes down in price (A Garmin eTrex of slightly lower specs can currently be had for $130), this technology should begin to be used for alternative uses (other than getting directions to the Walmart).

Potential uses could be in entertainment (locative games), art, r/c robotics, tracking and hopefully some things I haven't even thought of.

The device should be easy to program (with user designed modular libraries), and allow for modular hardware addition, such as WiFi, accelerometers, sensors and interface components. I've chosen the Arduino based RBBB from modern devices as the initial processor, because of the vast resources and ease of use associated to the Arduino microcontroller platform, and the tiny form factor of the RBBB.

For now, the cost of a unit comes in at about $130 with the addition of an FTDI cable and shipping, bringing the total closer to $160 on a per/unit basis. Obviously there will eventually be ways to get this cost down below $100, including a single circuit board, and some shared bulk ordering on components.

I've chosen the following initial components with some notes below:

Arduino RBBB
--tiny form factor, modular open design, Arduino based programming
20 Channel EM-406A SiRF III Receiver with Antenna
--excellent resolution, uses standardized NMEA protocol, power control via serial,
& excellent bang for the buck!
uVolts Nokia SGD-A LCD with speaker
--simple serial interface to audio & LCD, tiny modular form factor. Power control via serial
Sparkfun step-up power supply
--everything runs fine on 2 AA batteries, so far Ni-Mh & Alkelines both get the job done at unknown operating lengths (depending on use of sleep mode for LCD & GPS).

I will stabilize this version before the class on September 13th. Hopefully the intial builders can act as a team to clean up the libraries, and make the unit more modular, before we start re-addressing hardware options.

The name "GPS-A-Sketch" by-the-way is a dual reference to our first etch-A-sketch game program to be completed on September 20th in the class, and the Arduino "sketch" system. Corny, but I can't pass up double-meaning in names.

More info to come...
-Wil Lindsay