PICAXE

PICAXE is a brand of micro-controller, running inside PIC micro-controllers from Microchip. These chips come in many flavors and sizes, from 8 pins to 40. They are very cheap and come with free software for programming in BASIC (MAC, LINUX, Windows) or with flow charts (Windows).

PICAXE is a nice alternative to other micro-controllers used in education in that it's cheap if you already have an electronics lab, the software is free.

I have used PICAXE to make data-loggers, for light, temperature, and wind speed. I have also made a MIDI controller, where the PICAXE interprets potentiometer metrics into MIDI controller signals; this is useful for running TRAKTOR, see MIDI and DJ mixers.

The main web site for PICAXE is here: http://www.rev-ed.co.uk/picaxe/

Very nice site!

Hardware

As of 2010, the X2 series of PICAXE provides plenty of versatility and features. The 20X2 I have can operate from 1.8V to 5.5V, making it compatible with many different types and sizes of batteries. The 08M lacks much of the newer versatilities, but it is very small, 8 pins, and very cheap.