[NJARC] Star trek theremin goes arduino

[Thomas Lee]

Quick and easy Arduino-powered theremin
																				by Brian Benchoff
																			
																		
																	
																
																
																																			
[Martin] sent in a great guide
 to a simple Arduino based theremin. It's a very small build - just a 
single common IC and some passive components - and easy enough to build 
in an afternoon.
The
 theremin is based on a simple LC oscillator built around a 7400 quad 
NAND gate IC, a wire antenna, and a few caps and resistors. When a hand 
moves closer to the antenna, the frequency of the oscillator increases; 
when a hand moves away, the frequency decreases. On the software side, 
the oscillator is connected to the internal hardware counter of the 
Arduino. Every time there's a change in the voltage output by the 
oscillator (all the time, varying slightly with the distance from a hand
 to the antenna), the counter increases by one. This counter is tallied 
up over 1/10th of a second, and the distance from the instrumentalist to
 the theremin can be determined. From there, it's just outputting a 
frequency to a speaker.
All
 the code, schematics, and board layouts are available on [Martin]'s 
guide, and most of our readers probably have the parts to build this 
lying around their workbench. You can check out a video of [Martin]'s 
theremin in action on his guide.