We are going to build a simple robot arm which is controlled by hand and arm gestures. Basically, the robot arm follows the gestures of one's hands and arms. It is a different way of human-machine interaction. Its application is vast: precision manufacturing, surgery, wearable robots (such as exo suits), etc. General methodology: 1) get data of hand or arm motions with flex sensors attached to hand and arm; 2) process the data with RPi; 3) send data to the receiver of the robot arm and perform corresponding actions.