This paper introduces an intuitive and safe command approach for a quadrotor, where inertial and muscular gestures are used for semi-autonomous flight. A bracelet composed by gyroscopes, accelerometers, and electromyographic sensors is used to detect user gestures, then an algorithm is proposed to interprete the signals as flight commands. The main goal is to provide a wearable, easy-to-handle human-machine interface for users a to safely command this kind of vehicles, even for inexpert operators. Safety measures are incorporated in the scheme to further enhance the user's experience. Experimental tests are performed to validate the proposal.