EMG Hacking for Beginners!
Electromyography (EMG) is the measurement of skeletal muscle electrical activity through sensors placed on the skin. EMG can be used to measure both voluntary and involuntary movement. Because the electrical potentials are so small, you need a fairly high-gain preamp connected to the sensor to get useful measurements. This compact Muscle BioAmp BisCute sensor board is just the ticket for amateur EMG measurements!
It uses the tried and true LM324 quad op-amp to amplify the raw signal, as well as a 72-720Hz band-pass filter to get rid of signals outside the area of interest. This makes it much easier to interpret and display the gathered data. The kit is DIY, but it’s all through-hole soldering and there aren’t many parts, so even fairly new solderers shouldn’t have too much trouble assembling it.
The kit includes a 3-sensor lead as well as a band to help hold them in place. Alternatively, you can also buy disposable medical-grade adhesive-backed EMG sensors (the same type you’ll see used in hospitals) if you are going to be using the sensors on more than one person. They are quite inexpensive and it’s worth grabbing a bunch in bulk if you’re going to be doing a lot of experiments.
The output from this board can go directly into the ADC of any microcontroller, or even directly into an oscilloscope. Always make sure that your measurement devices are isolated from the mains supply using an isolation transformer, or run your devices from batteries — never attach devices like this to instruments that are plugged into the wall! Even your laptop should be unplugged if you are programming a microcontroller that’s connected to this board. Be aware of your environment and always think about safety when starting your journey into bio-hacking!