EMG controlled prosthetic arm

Electromyography (EMG) is an instrumental technique used for registering the electrical signals which occur when the fibers within a muscle contract on receipt of a motor command from the brain's motor cortex. In medical applications, the properties of the signals generated from the muscles can be used to diagnose muscular or nerve dysfunctions. In certain engineering applications, however, the signals are used as inputs for electrical or mechanical systems. Many engineering principles are based on the ability to achieve a large system gain wherein the input to the system may be small and insignificant but leads to an output that is large in quantity.This project is composed of three main parts that subsequently are the power supply circuit, EMG signal processing circuit with motor control and the hand prosthesis mechanism. The EMG signal processing part is composed of a differential amplifier, a bandpass filter and a half-wave rectifier. EMG signals are first amplified via the differential amplifier to a constant gain and are then re-amplified via the bandpass filter to the final gain. Bandpass filter cancels out the noise caused by the electronic parts of the circuit, movements of the arm or various environmental conditions. The analog signal is rectified with the half-wave rectifier and then ADC of microcontroller is fed by this rectified signal. The microcontroller makes its decision and controls the movement of the prothesis.