Wheelchair Mounted Robotic Arms (WMRA) can be used by people with severe motor skill impairment, such as SMA (Spinal Muscular Atrophy), Cerebral Palsy etc..., in order to achieve daily life tasks. Many of those systems have been presented in literature and are available on the market but they are really expensive and bulky. Instead we propose a simple robotic arm with 4 Degrees of Freedom (DOF), controlled by a cheap embedded platform in order to keep the size and the cost as low as possible. This paper presents the design and evaluation of a simple visual servoing control loop for the robotic arm based on a camera mounted on the arm end effector. A lot of attention has been given to the design process of an effective and more accessible human machine interface, in order to make the arm simply usable by the user. Tests and evaluations were performed on a simplified version of the final system prove the effectiveness of the proposed solution. However further optimization have to be achieved in order to make the whole system really usable in a real-word scenario.