A small wireless device embedded in an armband allows to interact with mobile devices in a subtle and unobtrusive way. The armband is meant to be worn under clothes and it detects discreet "motionless gestures", such as a short contractions of the upper arm (see the video below). These gestures can be used to activate functions of a mobile phone or PDA, such as sending a pre-defined message or rejecting an incoming call (see also the MyoPhone project). The armband provides haptic feedback through an embedded actuator. The device is, therefore, a self-contained input/output unit. Bluetooth wireless connectivity allows interfacing with standard mobile devices.

The motionless gesture recognition is based on the electromyogram (EMG): an electrical signal generated by muscular activity. EMG is used to recognize activity related to very subtle or no movement at all (isometric activity). If a gesture is recognised the device transmits via Bluetooth an appropriate message containing the device ID and the parameters describing the gesture (if any). The armband is designed to potentially fit any user; it does not require calibration or training to the muscles of individual people. The EMG controller does not occupy the users' hands, and does not require them to operate it; hence it is "hands free."

Papers describing the system were published in the proceedings of the CHI2005 and CHI2007 conferences.