Abstract: In a preferred embodiment, a device for indicating rotation of the head of a golfer during the process of hitting a golfball, which includes: a housing; a sensor including a pendulum switch disposed in the housing to sense the beginning of rotation of the head from an initial position, generally about the axis of the spine of the golfer, and to produce an output signal thereupon; a sound producing device activatable in response to the output signal to provide an audible signal to the golfer; an adjustment device to adjust the sensor so that the sensor will not produce the output signal when the head is in a desired position, but will produce the output signal when the head begins to rotate in the direction the golfball will be hit; and a manually initiated timing device to which the sensor is responsive to permit the sensor to produce the output signal only during a selected period of time after manual initiation of the timing device.

Abstract: A device for sensing and indicating movement of a golf player's head adapted to be worn upon the golfer's cap proximate the side of the head, the motion sensor adapted to sense motion of the golfer's head up and down and side to side, the motion sensor device outputting an electrical signal in accordance with movement acceleration sensed to a signal processing unit which generates a variable audio frequency electrical signal in accordance with electrical signal received from the motion sensor, and an audio output device receiving the electrical signals from the signal processing unit, the audio output device being such as an earphone worn in or near the golfer's ear to indicate to the golfer in real time motion made by his head at and during the time that he makes his golf swing.