Within this work a novel head gesture based interface for hands-free control of a collaborative robot is developed and evaluated. Based on previous work, robot control is divided into several control groups for intuitive head motion based control. The switching commands to select and switch between these robot control groups are given by four gestures performed with head movements. The head movements were measured using a nine-axis inertial measurement unit. The control of a robot with the novel interface was evaluated objectively as well as subjectively. The objective evaluation contains the measurement of time needed for the given control task and the number of trials for switching between the different groups of robot control. The subjective evaluation was carried out with a questionnaire. All subjects were able to perform the given task of controlling a robot arm with the head gesture based interface.