Transmitter and transmitting method of tire air pressure monitoring apparatus

摘要

A tire air monitoring apparatus includes transmitters (3) for wirelessly transmitting data regarding the inner pressure of tires (2) and a receiver (4) for receiving the data transmitted by the transmitters (3). Each transmitter (3) is powered by a battery (15). Each transmitter (3) includes a pressure sensor (11), which measures the inner pressure of the tire (2) at predetermined measuring intervals (tl). Each transmitter (3) periodically and wirelessly transmits data every time the pressure sensor (11) has taken a measurement a predetermined number of times. When the tire pressure changes by an amount that is equal to or greater than a predetermined upper limit value (P1, P2) during a predetermined judging time, the transmitter (3) performs an early data transmission. Therefore, an abnormality in the tire pressure is immediately communicated to a driver, and battery strength is conserved.