This project presents an inexpensive practical method for designing and constructing a myoelectric prosthetic arm and investigates the use of the forearm surface electromyographic signal for real time control of the prosthetic arm. The target is to achieve the grabbing movement of the hand, one of the most important functions that human hand performs. A single channel EMG sensor is employed to read the signals from the residual muscles of the amputee. Each finger of the five-fingered prosthetic arm is connected to a servo motor through a string. The designed prosthetic arm can grab an object and then release it.

The main structure of the arm has been made with wood. Each finger consists of four small parts connected with screw. A hole is drilled in each of these small parts to allow string to pass through. These strings were connected with metal geared servo motor. A spring at the backside of each finger supports and helps the finger return at its relaxed state.


SolidWorks Model

To control the prosthetic arm, the user first attaches the electrodes on his/her forearm. The electrical signal, generated because of the flexion of the targeted muscle is detected by the sensor. The signal is then sent to the arduino. Based on the value of the signal, the arduino takes decision and actuates the servo motors.


Electrode placement

If the voltage is increased due to the flexion of the muscles, the prosthetic arm actuates and grabs an object.To reduce the stress on the muscles of amputee, the arm will hold on to the object even if he/she relaxes his/her muscle. To release the object, he/she needs to contract the muscle for the second time.

We presented this project in a competition organised by IUT and secured the 2nd runner up place. The judges really appreciated us.


Me and my project mate(Shariful Sumon) with the prize

Project completion date: 2015