Abstract: A method of establishing a target pressure for a vehicle tire for storage in a receiver having a microcontroller where a sensor/transmitter combination is mounted on each wheel. After each tire is inflated to the target pressure the sensor/transmitters are sequentially triggered to send an identification code and a target pressure signal to the receiver for storage in memory. In an alternate embodiment, the target tire pressures are statistically averaged and a warning signal is generated if a single tire target pressure deviates a predetermined amount from the statistical average.

Abstract: A passive remote operating system is disclosed which may be employed to gain entry to a vehicle. A remote control, carried by a driver, periodically transmits a command signal whenever the remote control is moving. As the driver approaches the vehicle, the remote control comes within the reception range of a control circuit in the vehicle, which then receives the command signal. Receipt of the command signal activates the control circuit to begin sensing for an action by the driver, such as operation of a door handle, which indicates an intention to enter the vehicle. Upon sensing that action within a given period after receipt of the command signal, the doors of the vehicle are unlocked.

Abstract: An apparatus (10) allows atmospheric pressure into an environmentally sealed enclosure for creating an equilibrium that allows a sensor (28) make a proper measurement. A slot or opening (26) in the cover (14) exposes outside atmospheric air to a restricted portion of a gas permeable membrane (18). The membrane (18) allows a selected gas to pass through the membrane (18) creating the equilibrium in the housing (12). A gasket (16) positioned between the cover (14) and housing (12) seals the housing in an air tight manner except for the gases allowed in through the membrane (18). Pressure sensor (28) can then make a more accurate measurement. Apparatus (10) finds particular utility in a low pressure tire management system.

Abstract: A passive keyless entry system that is specifically adapted for use with automotive vehicles is designed to automatically unlock the vehicle as the operator approaches the vehicle. The system is further designed to automatically lock the vehicle as the operator, carrying the beacon, moves away from the vehicle. The system includes a portable beacon that is carried by the operator, a receiver/controller located in the vehicle, and an antenna connected to the receiver/controller for receiving the encoded transmission from the beacon. The beacon includes a motion sensor to conserve battery life when the beacon is stationary. Transmission between the beacon and the receiver/controller is characterized by a magnetically coupled radio frequency signal embodying differential phase encoded data with error correction coding of the data to enhance noise immunity and signal discrimination.

Abstract: A passive keyless entry system is specifically adapted for use with automotive vehicles. The system includes a portable beacon that is carried by a vehicle operator, a receiver/controller located in the vehicle, and an antenna connected to the receiver/controller for receiving an encoded transmission from the beacon. The system is designed to automatically unlock the vehicle as the operator approaches the vehicle. The system is further designed to automatically lock the vehicle as the operator, carrying the beacon, moves away from the vehicle. The beacon includes a motion sensor to conserve battery life when the beacon is stationary. Transmission between the beacon and the receiver/controller is characterized by a magnetically coupled radio frequency signal embodying differential phase encoded data with error correction coding of the data to enhance noise immunity and signal discrimination. In addition, the transmitted signal between the beacon and the receiver is continually changing in order to deter theft.

Abstract: A passive keyless entry system is disclosed that is specifically adapted for use with automotive vehicles. The system is designed to automatically unlock the vehicle as the operator approaches the vehicle. The system is further designed to automatically lock the vehicle as the operator, carrying the beacon, moves away from the vehicle. The system includes a portable beacon that is carried by the operator, a receiver/controller located in the vehicle, and an antenna connected to the receiver/controller for receiving the encoded transmission from the beacon. The beacon includes a motion sensor to conserve battery life when the beacon is stationary. Transmission between the beacon and the receiver/controller is characterized by a magnetically coupled radio frequency signal embodying differential phase encoded data with error correction coding of the data to enhance noise immunity and signal discrimination.

Abstract: A passive keyless entry system is disclosed that is specifically adapted for use with automotive vehicles. The system is designed to automatically unlock the vehicle as the operator approaches the vehicle. The system is further designed to automatically lock the vehicle as the operator, carrying the beacon, moves away from the vehicle. The system includes a portable beacon that is carried by the operator, a receiver/controller located in the vehicle, and an antenna connected to the receiver/controller for receiving the encoded transmission from the beacon. The beacon includes a motion sensor to conserve battery life when the beacon is stationary. Transmission between the beacon and the receiver/controller is characterized by a magnetically coupled radio frequency signal embodying differential phase encoded data with error correction coding of the data to enhance noise immunity and signal discrimination.

Abstract: A device mounted on a power transmission device of a vehicle is utilized for transmitting an RF signal when a predetermined parameter exists in the power transmission device wherein the RF signal is capable of being received at a remote location. An electromagnetic transducer provides alternating voltage as power which is applied to an oscillator including a crystal filter, a junction field effect transistor and a resistor. The alternating voltage is applied across a drain and a source of the junction field effect transistor. The crystal filter is connected between the drain and the gate of the junction field effect transistor while the resistor is connected between the gate and the source of the junction field effect transistor. A wire antenna has a first end which is connected to the drain of the junction field effect transistor and a second end which is connected to the source of the junction field effect transistor to prevent transmission of any RF signal until the predetermined parameter is exceeded.