Patent ID: 7068158

Claim:
A system for monitoring pressure of tires mounted on a vehicle, comprising: a sensor unit installed at each of the tires mounted on a vehicle and including at least a pressure sensor that produces an output representing air pressure of the tire and a transmitting antenna that transmits the output of the pressure sensor; a monitoring unit having a receiving antenna and an alarm section, the monitoring unit receiving the output transmitted by the pressure sensor through the receiving antenna, comparing the output with a predetermined value to determine whether the tire pressure is proper, and informing a result of the determination to an operator by the alarm section; a battery mounted on the vehicle and connected to the alarm section through an ignition switch to supply operating power to the alarm section; and an operating switch installed in a compartment of the vehicle to be operable by the operator for supplying the operating power to the alarm section regardless of the operating condition of the vehicle by connecting the battery to the alarm section, while bypassing the ignition switch.