In recent years, the research community has shown growing interest in adaptive, tendon-driven devices due to their lightweight, compact, and cost-effective designs. These features are made possible by utilizing underactuation, differential mechanisms, and structural compliance, providing a compact form and making such devices a very reasonable choice for the development of affordable, easy to control and easy to maintain prosthetic hands. Despite their long history and the considerable research efforts that have been put into their development, prosthetic hands are still suffering from being bulky, heavy, hard to control, and expensive. In particular, it remains challenging to control modern prosthetic hands with the residual limb muscles using traditional muscle-machine interfaces such as Electromyography. In this paper, we propose an anthropomorphic, light-weight, and affordable prosthetic hand equipped with a five output, series elastic differential mechanism and an armband utilizing a new muscle machine interfacing method that is called Lightmyography (LMG). LMG signals are used to discriminate between different hand gestures in real-time, as well as to control the contact forces exerted by the hand. The efficiency of the proposed prosthetic hand is experimentally validated through three different sets of experiments: i) force exertion experiments, ii) grasping experiments involving everyday life objects, and iii) real-time control using lightmyography signals.