Telemetry based shaft torque measurement system for hollow shafts

A hollow shaft torque measurement and telemetry system is provided for race cars. The system provides information on the torque delivered to each drive wheel of a race car while the race car is in motion. That information is valuable in attempting to maximize the speed during a race. The system operates under the high vibrations and temperature levels typical of a race car. A set of strain gauges, a transmitter, and batteries are installed inside one of the hollow shafts connected to a race car's drive wheels. The batteries provide power for the system. The strain gauges are mounted in an electrical bridge configuration so that they provide an electrical indication of torsion only. The strain gauges are connected to the transmitter. The transmitter converts that electrical indication of torsion to an FM radio signal, and has an automatic calibration circuit. The transmitter is connected to a rotating antenna over-wrapped with glass epoxy on the outside of the shaft. The FM radio signal is transmitted via the over-wrapped antenna. A whip antenna mounted on a stationary non-rotating part of the race car receives the FM radio signal from either or both hollow shafts. The whip antenna is connected to a specially hardened low power receiver mounted on a stationary part of the race car. The receiver receives the FM radio signal, demodulates and conveys a torque related voltage to the race car's indicator and data collection system.