Abstract: An electronic sensor circuit is provided which generates predetermined frequencies corresponding to the resultant force vector of the gravitational and inertial forces. There is further provided electronic circuit means for generating an audible response which increases in intensity in correspondence with the magnitude of the deviation of the force vector from a defined datum. In the preferred embodiment an electrolytic transducer is used to sense gravitational and inertial forces and a phase detection circuit is provided to monitor the output and control the input generator for selection of a frequency corresponding to the deviation occurring.