In the world of upper limb prostheses, few companies propose different kinds of hand, wrist and elbow prostheses but their control is often difficult to understand by the patients. We have decided to develop new myoelectric prosthetic arm (elbow, wrist and hand) by axing our development on the use of new technologies and user centered design methodology. In this paper, we are explaining the different kinds of prostheses currently manufactured their advantages and their drawbacks. Then, we explain our designing choices of the prosthesis and the movements it can realize. We detail the control chosen to simplify the use and the instrument of the product by the patient. In the last part, an adapted software is developed and used to validate experimentally the practice by the patient.