This article describes an open source project for automatic activation of an electromechanical arm using myo-electric signals, servo motors, Arduino-based microcontroller, and arm parts printed in a 3D printer. The objective is toautomatically detect the muscular stimuli related to an individual movement of the hand and reproduce the correspondingmovement in an electromechanical arm, using myoelectric sensors fixed on a muscle of the human arm. At the end, mus-cle contraction and relaxation related to human hand movements were successfully reproduced in the electromechanicalarm.