So you didn’t get bored with part 1 aye? You must be some type of masochist.
First, let’s start with the finale. So far I’ve managed to use the Myoware and Arduino to control an LED that signifies a flexed state of the prosthetic arm. I took that one step further to control a servo motor that was hooked up that would potentially close a hand. This video doesn’t show the calibration step or the Serial Monitor output of the Arduino.
Here is the code that I used. It is rough and not well documented, but I was just trying to get it to work.
BiomedMyoWareLedwcalibration – Feel free to email questions if something doesn’t make sense
The main meat of the code is spent in calibrating the sensor and determining a threshold EMG signal to be used to toggle the state. The red light(0-5s) is determining lowest threshold, it isn’t totally necessary now but later will be used. The yellow light (5-10s) is used to determine a threshold where the user will flex their arm a few times. The right threshold is the tricky part. Too low, and the arm will accidentally open/close when it may be very inopportune. Too high and simple tasks such as putting away silverware will leave the user extremely tired.
Disclaimer: The video above took me a good number of tries to get the LED working everytime I flexed my forearm. There were definitely a few misses and a few double signal grabs.
- Add in a delay to the signal grab if a “hit” is sensed to prevent getting a double trigger which would leave the hand in it’s current state.
- Experiment with different placement of electrodes.
- Try using quartz to lower resistance of skin to get a better signal (how would quartz be used in a final product?)
- Experiment with higher quality electrodes
- Get an actual electronics workbench that isn’t cluttered with better angle
- Grow cool facial hair so I can be in video.