This is the Neuron, a learn to solder kit I threw together for the 2012 Kansas City Maker Faire. On the surface it's just another easy to assemble "my first soldering project" blinker, but put a few of them together and you can make a light and touch reactive light show! It functions as your typical alernating LED blinker with a jumper in place, but remove the jumper and they mirror pulses of light detected on one LED to the other. Chain a large set of them together and they'll activated each other in sequence. They're also bi-directional so you can send a pulse one direction in a chain and send another back the opposite direction. A single Neuron firing can activate more than one Neuron, forming branching light shows as well! You can even use one in blink mode to act as a convenient light pulse source.Other features of note:Full assembly instructions availiable here: http://www.built-to-spec.com/blog/kit-instructions/neuron-build-instructions/You can see them on Adafruit Show-and-Tell here: http://www.youtube.com/watch?v=0SnvDkEhwSQ#t=20m31s And here's a quick video I did demoing a set of them at the hackerspace: https://www.youtube.com/watch?v=PmzQeHIHwlYGrab what's left of the v1.0 boards in my store: http://builttospecstore.storenvy.com/collections/120070-neuronsThe firmware was developed in AVR Studio 5, but should be easy to compile using avr-gcc under Linux.Note that in this version, the ISP header will not work with ISP programmers with inline current limiting resistors (like the tinyISP) once the LEDs are installed.