http://lcs.www.media.mit.edu/people/fredm/projects/cricket/
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The Cricket is a tiny computer, powered by a 9 volt battery, that can
control two motors and receive information from two sensors. Crickets are
equipped with an infrared communication system that allows them to
communicate with each other. Crickets are the result of cross-breeding our
work on Programmable Bricks with the wearable Thinking Tag. Like the Brick,
Crickets can be used for robotic applications, but because they are so
small, Crickets can be used for other investigations like body-monitoring
and data collecting.
The Cricket is based on the Microchip PIC series of microprocessor.User
programs are downloaded to the Cricket via its infrared communications
system. The Cricket has a button that when pressed triggers it to run the
program that was downloaded to it. LEDs on the Cricket indicate when it is
running a program or sitting idle, the state of the two motor outputs, and
indication of infrared transmission.
Crickets are programmed in a dialect of the Logo programming language, a
procedural language that includes constructs like if,repeat, and loop,
global and local variables, 8-bit numeric operations (addition, subtraction,
multiplication, division,comparison), motor and sensor primitives, timing
functions, atone-playing function, and a random number function.
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For stuff you can buy, at least there is Lego -
http://www.legomindstorms.com/
/cco