Looking for a way to pump up your next project? Let the Muscle Sensor v3 from Advancer Technologies do the heavy lifting!
This small, easy-to-use, 1″ × 1″ board measures muscle activation via electric potential; this is referred to as electromyography (EMG). The sensor measures, filters, rectifies, and amplifies the electrical activity of a muscle; as the muscle flexes, the output voltage increases, resulting in a simple analog signal that can easily be read by any microcontroller with an analog-to-digital converter (ADC), such as our A-Star or an Arduino.
The engineers here were pretty excited to play with these when we got our first samples, as many of us hadn’t used anything like it before. While thinking of various ways to test the sensor, a few of us remembered this ridiculously awesome video of Terry Crews making music with his muscles. (Gets me every time! #MuscleEnvy.) Without getting ahead of ourselves, we decided to try something much quicker and more straightforward with some of our electronics.
In the demonstration video at the beginning of this post, you can see the muscle sensor in action as it measures the muscle activity of my bicep. The demo uses the muscle sensor with a Maestro servo controller to update the position of a hobby RC servo based on how hard I flex. The setup was very simple; the analog output signal from the muscle sensor is connected directly to channel 0 on the Maestro, and the two boards share a common ground. The muscle sensor is powered by two 1S LiPo batteries and the Maestro and servo (connected to channel 1) are powered from a separate 6 V battery pack.
The Maestro script we used is very similar to the “Using an analog input to control servos” example script provided in the Maestro user’s guide with a couple of modifications. We changed the scaling of the input channel (since our signal was from 0 V to 3.7 V) as well as the channel numbers to match our setup. The whole script is only a few lines long:
# Sets servo 1 to a position based on the analog input of the Muscle Sensor v3. begin 0 get_position # get the value of the muscle sensor's signal connected to channel 0 6 times 4000 plus # scale it to roughly 4000-8092 (approximately 1-2 ms) 1 servo # set servo 1 accordingly repeat
We can’t wait to see all of the amazing things you come up with when you engage your brain (and your muscles) with this sensor!
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