Method and apparatus are disclosed for wireless backscatter with time-of-flight for vehicle communication. An example vehicle includes a communication module for Wi-Fi communication and a controller. The controller is to send a signal via the communication module upon identifying a passive-entry passive-start (PEPS) request and receive a backscatter signal from an electronic device. The backscatter signal is a reflection of the signal. The controller also is to determine a distance to the electronic device based upon the backscatter signal and perform the PEPS request upon determining the distance corresponds with the PEPS request.

A vehicle and method for controlling the same are provided to provide more reliable tire pressure information than the existing tire pressure detecting system using a method of calculating a wheel frequency once every predetermined reference vibration count. The vehicle includes a sensor unit that measures a wheel speed and a controller that divides a vibration count of wheel derived based on the wheel speed by a predetermined reference vibration count to calculate at least one frequency. The at least one frequency is analyzed to derive a state of pressure of a tire mounted on the wheel, and the tire pressure state to be output is adjusted to then be output.

An integrated tire sensor and reader system includes at least one sensor unit mounted a tire or a wheel. A reader is disposed remotely from the sensor unit. The sensor unit includes at least one sensor for measuring a parameter of the tire or wheel and an antenna for communicating with the reader. The sensor unit is configured to receive a radio frequency power signal from the reader and to transmit data to the receiver. The reader includes an antenna for transmitting the radio frequency power signal to the sensor unit to actuate the one sensor unit. Upon actuation of the sensor unit, the sensor measures the parameter of the tire or wheel, and data from the sensor is transmitted from the sensor unit to the reader.

A charger incorporated in a vehicle wheel supporting rolling bearing unit detects an output voltage of an electric generator and calculates a rotation speed of a hub. When a rotation speed of the hub is in a low speed state where a sensor and a wireless communication device are operated by electric power supplied by a battery, a frequency of wireless communication performed between the wireless communication device and a calculator disposed on a vehicle body side is changed according to the rotation speed of the hub or a traveling speed of a vehicle.

A tire pressure monitoring device is mounted on a wheel of a vehicle provided with a pneumatic tire. The device contains a tire pressure sensor and a transmitter which transmits signals wirelessly in transmission intervals, between which in each case there is a first transmission pause. A control device controls the sensor, the transmitter and the first transmission pause thereof. A source provides electrical energy to a rechargeable electric accumulator, in which electrical energy delivered from the source is stored until it is required. The state of charge of the rechargeable electric accumulator is monitored by a monitoring device and one or more of the first transmission causes is/are then ended as soon as enough electrical energy is stored in the rechargeable accumulator to operate the tire pressure monitoring device between two successive first transmission pauses until the conclusion of a predetermined number of transmission processes.

Example systems and methods for aligning tire pressure monitoring sensors on a vehicle are disclosed. An example disclosed method includes positioning the front wheels on first and second dynamometers. The example method also includes aligning, with the first and second dynamometers, the tire pressure monitoring sensors of the front wheels. The example method includes positioning the rear wheels on the first and second dynamometers. Additionally, the example method includes aligning, with the first and second dynamometers, the tire pressure monitoring sensors of the rear wheels.

A radio frequency identification (RFID) tag includes an antenna, an analog front end, a processing circuit, and memory. The analog front end includes a power circuit, a tuning circuit, a transmitter, and a receiver. The power circuit is operably coupled to convert a radio frequency (RF) signal into a power supply voltage. The tuning circuit, when enabled, adjusts an RF characteristic of the analog front end to tune power harvesting from the RF signal. The transmitter is operably coupled to transmit a response signal to the RFID reader via the antenna. The receiver is operably coupled to receive a command signal from the RFID reader, wherein the command signal is contained within a portion of the RF signal. The processing circuit is operable to interpret the command signal and generate the response signal.

A control unit supplies power and data through a rotary transformer to a sensor assembly disposed on a wheel. The data sent by the control unit to the sensor assembly is produced by modulation of the power signal using frequency shift key or amplitude shift key modulation. The sensor assembly converts the received power signal that power to operate the circuitry and sensor assembly, converts the FSK or ASK data signal, and sends sensor data back to the control unit through the rotary transformer by load modulation. The control unit demodulates the load modulated sensor data.

Provided is a tire pressure detection system that can be operated stably for a long period of time by using, as a power source, a secondary battery having little characteristic deterioration under a high temperature environment, e.g. in a situation in which the battery is maintained for a long period of time in a fully charged state under a high temperature environment, while having excellent low temperature characteristics. A tire pressure detection system 1 includes: an air pressure detection device 10 that detects an air pressure inside a tire; and a secondary battery 20 that supplies power to the air pressure detection device 10. The secondary battery 20 is a lithium secondary battery that includes a negative electrode containing a lithium alloy as an active material and a positive electrode.

The present invention provides a MEMS and a sensor having the MEMS which can be formed without a process of etching a sacrifice layer. The MEMS and the sensor having the MEMS are formed by forming an interspace using a spacer layer. In the MEMS in which an interspace is formed using a spacer layer, a process for forming a sacrifice layer and an etching process of the sacrifice layer are not required. As a result, there is no restriction on the etching time, and thus the yield can be improved.