Abstract: A brushless D.C. motor has a rotor with a plurality of magnets secured to a mounting surface. Each magnet has an RFID tag secured to a magnet surface, with each RFID tag having stored therein a unique identification character serving to identify the magnet. A stator has a plurality of pole teeth separated by slots, each pole tooth having a power coil wound thereabout. A plurality of RFID interrogation antennae are mounted adjacent the pole teeth. An RFID reader generates r.f. interrogation signals broadcast by the antennae to the RFID tags. The RFID tags respond by broadcasting the unique identification character whenever an interrogation signal is sensed as the tag enters the region of a pole tooth. This position and magnet identification information is received by the RFID reader, which processes the information and sends it to a motor controller and driver unit, which supplies operating power to the individual power coils.

Abstract: A tire parameter sensor unit for monitoring one or more vehicle tire parameters such as internal tire pressure and temperature and developing a permanent log of the operational history of the tire. The sensor unit has a power system, a processor/transmitter, a radio time clock, one or more sensors, and a memory mounted on a substrate. This assembly is permanently attached to the tire in the side wall or tread wall. Initial tire identification information is stored in the memory upon tire fabrication. During the lifetime of the tire, operational information specifying the tire operating conditions (pressure, temperature, etc.) is permanently stored in the memory along with real time data. The operational information and real time data can be read out from memory to provide the history log.

Abstract: A tire parameter sensor unit for monitoring one or more vehicle tire parameters such as internal tire pressure and temperature and developing a permanent log of the operational history of the tire. The sensor unit has a power system, a processor/transmitter, a radio time clock, one or more sensors, and a memory mounted on a substrate. This assembly is permanently attached to the tire in the side wall or tread wall. Initial tire identification information is stored in the memory upon tire fabrication. During the lifetime of the tire, operational information specifying the tire operating conditions (pressure, temperature, etc.) is permanently stored in the memory along with real time data. The operational information and real time data can be read out from memory to provide the history log.

Abstract: A “coil-on-a-chip” RFID tag having an rfid integrated circuit and an antenna contemporaneously formed on a substrate. The antenna is a helical multiple layer, multi-turn coil having an axis of revolution oriented at an angle, preferably ninety degrees, with respect to the major body plane of the rfid integrated circuit. The coil has a central opening with an annular core of magnetically permeable material. The RFID tag has an increased operating range over known ID tags.

Abstract: A battery powered vehicle tire pressure sensor system has a power saving unit which controls the application of electrical power to the system as a function of tire speed to prolong battery life. The power saving unit has a power control switch which is responsive to tire angular speed. Each sensor assembly of the system is mounted on or in the side wall of a pneumatic tire to generate signals representative of tire pressure whenever power is applied. A processor periodically samples the signals. When the processor determines that the tire pressure is outside a safe range, an r.f. generator is activated by the processor to generate an unsafe tire pressure signal. This signal is converted by a receiver to a warning for the driver.

Abstract: An RFID tag having an rfid integrated circuit and an antenna is combined with a first passive antenna circuit to provide an extended operating range. The first passive antenna circuit has a first coil and a first capacitor to tune the passive antenna circuit to a resonant frequency the same as the operating frequency of the RFID tag. The first coil has a central opening larger than the size of the antenna. The passive antenna circuit is arranged with the antenna located in the central opening of the coil, preferably in a co-planar manner, to promote inductive interaction therebetween. A second passive antenna circuit essentially identical to the first, but having larger dimensions, is positioned with the coil of the second passive antenna circuit surrounding the first coil to extend the operating range even further.

Abstract: A battery-less tire parameter sensor system for monitoring a vehicle tire parameter such as pressure and temperature. A sensor assembly has a power system, a processor/transmitter, a sensor, and a power coil mounted on a substrate. This assembly is mounted on or in the side wall or tread wall of a tire. A magnet is mounted on the vehicle in proximity to the path of the power coil during tire rotation. The moving power coil passes through the magnetic field and generates operating voltage for the sensor assembly components. The power system includes a voltage multiplier, a voltage regulator, and a storage capacitor. Two or more sensor assemblies can be mounted on the same tire to monitor different parameters.

Abstract: A battery-less tire parameter sensor system for monitoring a vehicle tire parameter such as pressure and temperature. A sensor assembly has a power system, a processor/transmitter, a sensor, and a power coil mounted on a substrate. This assembly is mounted on or in the side wall or tread wall of a tire. A magnet is mounted on the vehicle in proximity to the path of the power coil during tire rotation. The moving power coil passes through the magnetic field and generates operating voltage for the sensor assembly components. The power system includes a voltage multiplier, a voltage regulator, and a storage capacitor. Two or more sensor assemblies can be mounted on the same tire to monitor different parameters.

Abstract: A battery powered tire pressure sensor system with a high sensitivity stretch sensor assembly having a variable resistance longitudinal displacement characteristic. The stretch sensor assembly has at least two juxtaposed stretch sensors, each with a first layer bearing the variable resistance element and a second support layer. The sensor assembly is mounted on or in the side wall of a pneumatic tire so that the assembly is displaced by the tire side wall and the resistance is a function of internal tire pressure. The assembly is coupled to a processor which samples the resistance of the stretch sensor assembly periodically. When the processor determines that the pressure is outside a safe range, an r.f. generator is activated by the processor to generate an unsafe tire pressure signal. This signal is converted by a receiver to a warning for the driver. A power saving unit controls application of electrical power to the system as a function of tire speed to prolong battery life.

Abstract: An external mount tire pressure sensor system with a stretch sensor having a variable resistance longitudinal displacement characteristic. The stretch sensor is coupled to a processor which samples the resistance of the stretch sensor periodically. The sensor body is attached to the external side wall of a pneumatic tire so that the body is displaced by the tire side wall and the resistance is a function of internal tire pressure. When the processor determines that the pressure is below a threshold value, an r.f. generator is activated by the processor to generate a low tire pressure signal. This signal is converted by a receiver to a warning for the driver.

Abstract: An external mount tire pressure sensor system which substantially reduces the effect of centrifugal force on tire pressure measurements. A sensor has a main guide body portion with two parallel leg portions each having a central bore. A slider element is slidably mounted in each leg portion, and the two slider elements are mechanically connected for translatory movement in unison. A spring urges the slider elements to a neutral position. The sensor attaches to a tire valve stem. Gas from a tire encounters one of the slider elements and urges it in opposition to the spring force. The differential interconnection between the two slider elements cancels out the effect of the centrifugal force when the wheel rotates. A stiff flexible wall section enables the axis of the sensor to be aligned with the wheel radius to optimize performance.

Abstract: An external mount tire pressure sensor system which substantially reduces the effect of centrifugal force on tire pressure measurements. A sensor has a main guide body portion with two parallel leg portions each having a central bore. A slider element is slidably mounted in each leg portion, and the two slider elements are mechanically connected for translatory movement in unison. A spring urges the slider elements to a neutral position. The sensor attaches to a tire valve stem. Gas from a tire encounters one of the slider elements and urges it in opposition to the spring force. The differential interconnection between the two slider elements cancels out th effect of the centrifugal force when the wheel rotates. A stiff flexible wall section enables the axis of the sensor to be aligned with the wheel radius to optimize performance.

Abstract: A self-authenticating intelligent document in sheet medium form has an information storage and transfer circuit including an RFID integrated circuit and an antenna. When information is formed on the surface of the sheet medium by printing, an identical version of the visible information is stored in read-only fashion in the circuit using inductive transfer. To verify the authenticity of the document, the electronic version stored in the circuit is read out and compared with the visible version. When the two versions are identical, the document is authentic. A visible indicator is attached to the sheet medium and is illuminated whenever information is being accessed from the circuit to aid in locating a sought document stored with other documents. To minimize inductive interaction between circuits on adjacent documents, the locations of the circuits on the sheet media are staggered. The locations of the visible indicators are also staggered to facilitate viewing when activated.