Initial report by [[~ecl303 | Ezer Longinus]], 23, 02, 2012

Electromyographic sensors measure the electrical activity produced by the muscle during contraction. When muscles are active they generate an electrical potential. That potential can be read and measured. Electromyography has mostly been in use in the medical field and rather pricey, but with cheaper microcontrollers and relatively simple schematics it is possible to build a consumer grade version.

Sources

The original sensor I built was through Charleton University. The AD620, OP97, and the LM741 chip can be purchased through digikey. The only other anomaly are the two 24.9K resistors, which you can also pick up at digikey. The other parts are standard parts that you can pick up either at radioshack or order from any electronic supplier.

I had also found that Advancer Technologies has a kit and tutorial on building your own EMG sensor. The principle is the same, but the chips and layout is different. Again you can purchase the INA106 and TL072 from digikey. And all the other electronic parts can be purchases at any electronic store. Obviously you can purchase them from digikey, but finding relatively simple things on that website can be an art in and of itself.

Applications

Some non medical uses of EMG:

Electrical Characteristics

Since this is a sensor you have to build, and there are different versions of the schematic I'm putting links to the IC chips that are used.
Charleton University Schematic

Advanced Technologies Schematic

Schematics

Charleton University Schematic

Advanced Technologies Schematic

Code Sample

This is coming.

Behavior

When the EMG unit, based on the Charleton University schematic was first build, the reading that were received were a little erratic. Since the amplifier was at such a high gain, looking for pico volts of change, I was getting all kinds of noise. It seems obvious in retrospect, but at the time I was not certain as to what was causing this. At the time I built a RC filter to get rid of some of the noise, but after doing it programmatically proved a little more accurate and responsive at the time.

Applications Notes

Telemyograph Project. I helped to make the EMG portion of this project