EMG, or electromyography, is a technique for measuring electrical muscle signals. It can be used for diagnostics, and such signals can also be applied to control prostheses or other devices. While a seemingly exotic technique, experiments correlating electricity and muscle movement have been going on for over a century. If you’d like to try your hand (activating muscles) at electromyography, then the uMyo wireless EMG device by Ultimate Robotics provides the tools to get you started.
The device takes the form of a circuit board, held in place via an athletic strap wrapped around your forearm, or presumably your upper arm or even leg with a bit of stretching and/or modification. The circuit board measures muscle inputs using the included gel or dry electrodes, and the system’s snap connectors can be used to apply wet electrodes as well.
The device transmits muscle inputs wirelessly and can work with an ESP32 without additional hardware. Arduino-style boards can be used with the addition of an nRF24 radio module. Multiple devices can be attached to the same arm to read different muscle group inputs, and up to 12 devices can communicate wirelessly with a single Arduino/ESP32. With proper processing, an array of sensor inputs could be combined for gesture detection or another usage as desired.
You can see it in action in the video below, using two sensors in tandem. For more info on this project and its development, check out the uMyo project log on Hackaday.io.