Abstract: An erroneous start is controlled based on vibrations of a tire, irrespective of a poor visibility or an algorithm of an image processing. A tire-side unit detects a vibration of a tire when the tire has collided with a wheel stop or the like, and outputs collision data to a vehicle-side unit. The vehicle-side unit determines an erroneous start of the vehicle. Therefore, the erroneous start of the vehicle can be controlled without being affected by the poor visibility or the algorithm of the image processing as in a case of utilizing a camera or a radar.

Abstract: Data representing a ground contact time of a tire is transmitted from a tire side device, and received by a vehicle side device to calculate the ground contact time of the tire, to thereby calculate a ground contact length of the tire at that time. In a situation where a tire air pressure may change such as a tire exchange, the ground contact length at that time is set as a reference ground contact length, and a determination reference value is set on the basis of the reference ground contact length. As a result, the relative determination reference value corresponding to the tire type can be set, and a variation of the reduction rate of the tire air pressure when it is determined that the tire air pressure is reduced can be reduced. As a result, the reduction in the tire air pressure can be detected with high precision regardless of the tire type.

Abstract: A communication device changes an applied voltage output from a voltage circuit, and allows a capacitance measuring device to measure the respective capacitance values of a variable capacitance element before and after a change in the applied voltage. The communication device calculates a voltage correction value for correcting an initial variation of the capacitance value of the variable capacitance element using the respective capacitance values of the variable capacitance element before and after the change in the applied voltage, and respective applied voltage values before and after the change, and a correction voltage for canceling the initial variation in the capacitance value of the variable capacitance element, and outputs the correction voltage from the voltage circuit.

Abstract: A road surface condition estimation device includes a tire side device and a vehicle side device. The tire side device includes a vibration detection unit attached to a back surface of a tire tread and outputting a detection signal indicating a tire vibration magnitude, a signal processing unit, and a transmitter. The signal processing unit extracts a ground contact duration during which a portion of the tread corresponding to an arrangement position of the vibration detection unit is in contact with a ground, and calculates a high frequency component level of the detection signal detected during the ground contact duration as road surface condition data. When the ground contact duration is ended, a transmission trigger is transmitted to the transmitter and the transmitter transmits the road surface condition data. The vehicle side device estimates a road surface condition of the travelling road based on the road surface condition data.

Abstract: A road surface condition estimation device includes a tire side device and a vehicle side device. The tire side device includes a vibration detection unit outputting a detection signal indicating a tire vibration magnitude, a signal processing unit, and a transmitter. The signal processing unit extracts a ground contact duration during which a portion of the tread corresponding to an arrangement position of the vibration detection unit is in contact with a ground, calculates a high frequency component level of the detection signal detected during the ground contact duration, counts cumulative rotation number of the tire, and corrects the level of the high frequency component based on the cumulative rotation number of the tire. The transmitter transmits corrected level of the high frequency component as road surface condition data. The vehicle side device estimates a road surface condition of the travelling road based on the received road surface condition data.

Abstract: An opening area between twisted portions of a pair of twisted wires is arranged to be opposite to an opening area of an aperture antenna of each of communication apparatuses. Thus, the use of the pair of twisted wires permits division of electric power among the communication apparatuses and also communication of signals. In particular, among the opening areas between the twisted portions of the pair of twisted wires, only an opening area, which is in between the twisted portion and the twisted portion and is opposite to the aperture antenna, is formed to be larger than a different opening area. This provides a vehicular power line communication system and a transmitter in the system; the system strengthens electromagnetic induction connection between the transmitter and the receiver to permit power line communication.

Abstract: In a vehicular control device, an operating intention detection unit is disposed on a tire or wheel rim of a vehicle to detect an operating intention of a user relative to an opening/closing body of the vehicle. An operating intention acquisition unit is disposed on the vehicle body of the vehicle to acquire the operating intention. An ID code acquisition unit acquires, from a mobile device carried by the user, an ID code that identifies the user or the mobile device. An ID code determination unit determines whether the ID code is correct. The condition establishment determination unit determines, based on the operating intention of the user and on the result of ID code determination, whether an output condition for outputting operating instruction information that designates an operation of the opening/closing body is established. An output unit outputs the operating instruction information when the output conditions are established.

Abstract: A tire device includes a vibration power generating element, a signal processing unit, and a transmitter. The vibration power generating element is arranged inside a tire and outputs a voltage corresponding to a time variation of a vibration generated in a tread of the tire. The signal processing unit is disposed inside the tire and performs signal processing on the voltage outputted from the vibration power generating element. The transmitter is arranged inside the tire and sends data subjected to the signal processing in the signal processing unit to a device provided outside the tire. The signal processing unit and the transmitter are driven by power generated in the vibration power generating element.

Abstract: In an antenna, a first element is connected to a GND of a feeder, on the same plane as a GND of a wireless circuit, and isolated from the GND of the wireless circuit. A second element is on the same plane as the GND of the wireless circuit and a first end connected to the first element and a second end as an open end. The third element has a first end connected to a power source of the feeder and located in a region occupied by the first element perpendicularly to the first element so that its first end source faces down. The fourth element has a first end connected to a second end of the third element and a second end as an open end, is parallel to the first element, and is perpendicular to a line connecting the first and second ends of the second element.

Abstract: The communication system includes a first communication device, a second communication device, and a third communication device. The first communication device outputs a high frequency alternating current power, and a power receiving circuit of the second communication device receives the high frequency alternating current power via a second antenna. A power line is connected between the second antenna and the power receiving circuit. A first power line has a first semicircle portion and a second power line has a second semicircle portion. The first and second semicircle portions are combined together to provide a loop-shaped antenna. The third communication device receives the high frequency alternating current power output from the loop-shaped antenna. At least two of the first, second, or third communication devices transmit or receive communication signals using respective antennas. The first and second power lines are twisted with each other at a portion other than the loop-shaped antenna.

Abstract: In a communication system, nodes are coupled to a transmission path in a bus topology. The nodes communicate with each other via the transmission path using communication signals that have a communication frequency and are synchronized with a power supply signal. Each of the nodes includes a coupling portion that transmits and receives the communication signal and the power supply signal using electromagnetic induction in non-contact with the transmission path. Each of the nodes determines whether a collision of the communication signals occurs on the transmission path based on a voltage level of a signal that has the communication frequency and is induced at the coupling portion.

Abstract: A communication device changes an applied voltage output from a voltage circuit, and allows a capacitance measuring device to measure the respective capacitance values of a variable capacitance element before and after a change in the applied voltage. The communication device calculates a voltage correction value for correcting an initial variation of the capacitance value of the variable capacitance element using the respective capacitance values of the variable capacitance element before and after the change in the applied voltage, and respective applied voltage values before and after the change, and a correction voltage for canceling the initial variation in the capacitance value of the variable capacitance element, and outputs the correction voltage from the voltage circuit.

Abstract: A wireless communication system includes a mobile device carried by a user and an in-vehicle apparatus equipped to a vehicle and communicatively connected with the mobile device. The in-vehicle apparatus includes a transmission unit, a transmission control unit, a reception determination unit, and a position determination unit. The transmission unit transmits low-frequency band request signals generated by spread modulating transmission data with predetermined spreading factors. The transmission control unit controls the transmission unit to generate and transmit first and second request signals having first and second attainable ranges by spread modulation using first and second spreading factors, respectively. The reception determination unit performs reception determination to response signal transmitted from the mobile device in response to the request signal.

Abstract: A wireless communication system includes a mobile device carried by a user and an in-vehicle apparatus equipped to a vehicle and communicatively connected with the mobile device. The in-vehicle apparatus includes a transmission unit, a transmission control unit, a reception determination unit, and a position determination unit. The transmission unit transmits low-frequency band request signals generated by spread modulating transmission data with predetermined spreading factors. The transmission control unit controls the transmission unit to generate and transmit first and second request signals having first and second attainable ranges by spread modulation using first and second spreading factors, respectively. The reception determination unit performs reception determination to response signal transmitted from the mobile device in response to the request signal.

Abstract: An onboard apparatus control system is disclosed. The onboard apparatus control system includes a portable apparatus and an in-vehicle apparatus which controls an onboard apparatus according to position of the portable apparatus. From multiple transmitting antennae, the in-vehicle apparatus transmits pulse pattern signals with different transmission frequencies at an overlapping timing, so that the pulse pattern signals are radio waves whose intensities are changed stepwise according to different patterns. The portable apparatus receives the radio waves transmitted from the multiple transmitting antennae. The position of the portable apparatus with respect to the vehicle is determined based on a combined pattern of the received pulse pattern signals, which a receiving unit is to receive at location with respect to the vehicle.

Abstract: In a power line communication system, a master uses a twisted pair wire as a power line and a communication line and outputs a power signal and a data modulation signal to a slave. The slave includes an aperture antenna, a power monitoring portion, and a determining portion. The aperture antenna receives the power signal via the twisted pair wire by electromagnetic induction coupling of an electromagnetic field generated at the twisted pair wire in accordance with an applied current of the twisted pair wire. The aperture antenna has an aperture region facing an aperture region between twists of the twisted pair wire. The power monitoring portion monitors a power of the power signal received via the first aperture antenna. The determination portion determines whether to use another operation power received via the twisted pair wire on the basis of the power monitored by the power monitoring portion.

Abstract: A vehicular power line communication system includes a master and a slave. The master uses a pair of twisted wires, whose far ends are connected to each other to be loop-shaped, as a power line and a communication line. The master thereby outputs high-frequency signals via the pair of twisted wires, transmitting an electric power and data modulation signals. The slave includes an aperture antenna being loop-shaped to receive data modulation signals using an electromagnetic induction connection in an electromagnetic field generated in the pair of twisted wires in response to an energization current of the pair of twisted wires. The slave further includes an error rate monitor circuit which monitors an error rate of data which are obtained from demodulation of the data modulation signals received via the aperture antenna.

Abstract: A vehicular power line communication system includes a looped twisted pair wire, a master, and a slave. The master outputs a high-frequency signal to the twisted pair wire to transmit power and a signal. The slave includes a looped aperture antenna that receives high-frequency power of the twisted pair wire and a received power measurement portion that monitors received power received at the aperture antenna. The aperture antenna includes an aperture region facing an aperture region between twisted portions of the twisted pair wire.

Abstract: An antenna apparatus includes: a ground substrate; and a loop antenna having first and second polarized wave surfaces, which are perpendicular to the substrate. The substrate provides an antenna, which is excited and vibrated together with the loop antenna. The antenna has a first polarized wave component in parallel to the first polarized wave surface and a second polarized wave component in parallel to the second polarized wave surface. A polarized wave ratio between the first polarized wave component and the second polarized wave component in the substrate is substantially equal to a polarized wave ratio between the first polarized wave surface and the second polarized wave surface in the loop antenna.

Abstract: An opening area between twisted portions of a pair of twisted wires is arranged to be opposite to an opening area of an aperture antenna of each of communication apparatuses. Thus, the use of the pair of twisted wires permits division of electric power among the communication apparatuses and also communication of signals. In particular, among the opening areas between the twisted portions of the pair of twisted wires, only an opening area, which is in between the twisted portion and the twisted portion and is opposite to the aperture antenna, is formed to be larger than a different opening area. This provides a vehicular power line communication system and a transmitter in the system; the system strengthens electromagnetic induction connection between the transmitter and the receiver to permit power line communication.