fredzhang7/proesthetic-hand

A very cheap and affordable prosthetic hand built with strings, plastics, and electromyography sensors

DIY Prosthetic Hand

Aesthetics

Inner Look

Outer Look

Journal of Progress

1. Electromyogragy (EMG) Test
   

2. Mechanics Test
   

3. Torque↑ Test
   

Challenges

1. No alchohol nor cotton sticks available at home to clean my skin for accurate EMG readings
2. The prosthetic hand user may use different batteries
3. No multimeter available to detect any potential short circuits
4. Not enough power from the Servo motors to curl the fingers enough to grab things
5. Little to no Serial data support on Raspberry Pi

Solutions

1. Used tape to remove oil, dust, and other dirty particles from my forearm before testing
2. Read the voltage outputs in intervals and curl the prosthetic fingers only if consecutive intervals produce consistent results
3. Always left a 220Ω resistor in the circuit before completing any circuits & used small LED lights to test if a circuit works as intended
4. Repositioned the servo motors, as shown in the Torque↑ Test above
5. Switched to Arduino Uno Rev3

Detection V1

• Assuming there're no abnormal spikes in voltage outputs, it's fairly accurate. However, muscle sensors bought from Amazon sometimes give off abnormal spikes in the voltage outputs

Detection V2

• Only tested this once, but solved the abnormal spikes problem by tracking the lowest voltage reading and analyzing the history of 20 voltage readings