A pressure transducer assembly mountable in an interior of a tire for sensing a pressure of a fluid in the tire comprising: a sensor housing having a first compartment in fluid communication with the fluid; a second compartment separated from the first compartment by a divider slideably engaged with and removable from the sensor housing; the divider having disposed thereon a circuitry; the circuitry including a pressure transducer in fluid communication with the first compartment, and a transmission circuit coupled to the pressure transducer for transmitting a signal responsive to the internal pressure to a remote location; a removable power source coupled to the circuitry contained entirely within the second compartment; and a cover sealingly engaged with the housing and the divider such that the second compartment is not in fluid communication with the first compartment. A method of sensing the tire pressure and communicating a signal responsive to the tire pressure to an external receiver located in a remote location is also disclosed.

A low tire pressure warning system includes a tire pressure sensor constructed to be mounted within each of the tires on the wheels of a vehicle. Each tire pressure sensor includes a pressure switch coupled to a transmitter and a battery, with the pressure switch being constructed to connect the battery to the transmitter so as to activate the transmitter when pressure within the tire drops below a low value. A receiver is constructed to be mounted within the vehicle in communication with the transmitters and a low tire pressure warning indicator is coupled to the receiver so as to be activated when the receiver receives a signal from any one of the transmitters.

A tire condition monitoring system (1) comprises a wheel transmitter unit (2) for each wheel of a vehicle. The transmitter unit is mountable in the wheel and has sensors (9, 10) for sensing pressure and temperature in and rotation of the wheel. Signals from the sensors are processed by a processor (9) to produce data which is transmitted via a radio frequency transmitter (23). The data is transmitted with data representing a unit identity code. Transmitted data is received by a receiver unit (5, 6, 7) where it is analyzed to determine the condition of the tire. The receiver unit includes a user operable input for setting threshold limits for the temperature and/or pressure such that if a threshold is passed an alarm is sounded. Each wheel transmitter unit includes a power supply and is arranged so that power is only applied during the sensing and transmission of data. Intervals between transmissions of data can be varied depending on whether rotation of the wheel has been sensed.

An electronic tire maintenance system is provided for measuring a parameter of a device at a first location. The system includes a sensor for measuring the device parameter and generating a data signal representing the measured parameter. The system also includes a microprocessor coupled to the sensor for activating the sensor on a first periodic basis to measure the device parameter. The microprocessor includes a memory for storing the generated data signal representing the measured parameter. A transmitter and a receiver are coupled to the microprocessor. The microprocessor periodically partially awakens to determine, on a second periodic basis, if a received transmission is a valid interrogation signal and, if so, fully awakens and responds to the valid interrogation signal, via the transmitter, by at least transmitting the last stored measured parameter. In one embodiment, the device is a tire tag mounted inside a tire that measures tire data and transmits that data to a remote source in response to an interrogation request, an alert condition, or automatically on a periodic basis.