Abstract: Selected vehicle operational parameters such as tire pressure, wheel temperature and vibration are sensed by sensors mounted on wheel modules secured to the individual vehicle wheels. The sensed parameters are converted to digital format and the resulting digital data is manipulated to determine if the data falls within predetermined operating ranges. The data and information resulting from the manipulation are used to modulate an RF signal transmitted to another location on the vehicle. Additional parameters are sensed at the second location, and calculations are performed on the data received from the wheel modules and the data sensed at the second location to display operational, efficiency and safety information to the vehicle operator and to make such information available to others such as vehicle owners and maintenance personnel.

Abstract: A tire monitor includes a pressure sensor, a temperature sensor, an A/D converter, and a microprocessor. The microprocessor has a sleep mode for conserving power and an output of the microprocessor controls the power applied to the pressure sensor and to the temperature sensor. A modulator and antenna are coupled to the microprocessor for transmitting data from the tire. Coupling between a monitor and a receiver is enhanced by extending a receiving antenna downwardly from the chassis of the vehicle, e.g. from the frame of a tractor.The tire monitor is fabricated on a small printed circuit board with terminals for programming or encoding each monitor with a unique identification code during manufacture of the monitor. Terminals are also provided for disabling the transmitter with a jumper until the monitor is installed in a tire.