**5.2. Thresholding and motor drive**

The control of robotic prosthesis is provided through the thresholding technique [21]. Once the signal is received in digital format, taking all necessary considerations as described before, a suitable threshold is applied to that particular quantized digital signal.

Before applying the threshold, the digital quantized signal is to be observed properly. A threshold value should then set be accordingly. It is recommended to set the threshold value to a point which is less than half the digital quantized output of the EMG signal. When the digital signal exceeds this threshold, the microcontroller should set an output pin to '1' and '0' otherwise [21]. E.g. if the maximum value of the digital quantized signal is 750 (decimal value) then we can set a threshold of 275. This signal is forwarded to an H-bridge or a motor driver in order to drive the respective electric motors of a robotic mechanism.

The motor driver should be designed or selected according to our requirements of electric motor. Usually a motor driver which can drive a 12V motor and handle up to 4A current can adequately meet requirements for a robotic arm.
