Many common activities of daily living like open a door or fill a glass of water, which most of us take for granted, could be an insuperable problem for people who have limited mobility or impairments. For years the unique alternative to overcame this limitation was asking for human help. Nowadays thanks to recent studies and technology developments, having an assistive devices to compensate the loss of mobility is becoming a real opportunity. Off-the-shelf assistive robotic manipulators have the capability to improve the life of people with motor impairments. Robotic lightweight arms represent one of the most spread solution, in particular some of them are designed specifically to be mounted on wheelchairs to assist users in performing manipulation tasks. On the other hand, usually their control interface relies on joystick and buttons, making the use very challenging for people affected by impaired motor abilities. In this paper, we present a novel wearable control interface for users with limb mobility impairments. We make use of muscles residual motion capabilities, captured through a Body-Machine Interface based on a combination of head tilt estimation and electromyography signals. The proposed BMI is completely wearable, wireless and does not require frequently long calibrations. Preliminary experiments showed the effectiveness of the proposed system for subjects with motor impairments, allowing them to easily control a robotic arm for activities of daily living.