Limor Fried, creator of the very cool x0xb0x 303 DIY project, has released MIDIsense, described as “a simple, yet extensible sensor interface system for artists, musicians and others interested in experimenting with sensors.”
The MIDIsense boards provide a simple way to integrate various common sensors with existing software such as Max/MSP, Ableton Live, etc. or directly to a synthesizer/sequencer with a MIDI in jack. Interface boards are available as kits.
The kit is available for $50 including all parts.
Graphical configuration/calibration software is written in wx/Python and is available as a MacOS X executable or source for Linux. A Windows version is planned to be released soon.
An example tutorial is available at Fried’s site that discusses using the kit to make a laser harp.