Circuit arrangement for a tire pressure warning device and tire pressure detecting method implemented using the tire pressure warning device

A circuit arrangement for a tire pressure warning device, the tire pressure warning device being mounted to an inflation valve on every tire of a car, and including a case internally provided with a printed circuit board, the circuit arrangement comprising a detection circuit provided on the printed circuit board and consisting of a pressure sensing and measuring unit and other electronic elements, and a signal receiving circuit internally provided in the car;

• the detection circuit including:
• an air pressure sensor consisting of the pressure sensing and measuring unit and an amplifying circuit;
• the pressure sensing and measuring unit being provided on one side of the printed circuit board facing toward the inflation valve of the tire for measuring tire pressure of the tire and outputting a voltage value, which is an analog signal corresponding the measured tire pressure and is amplified by the amplifying circuit;
• an amplifier being connected to the air pressure sensor for amplifying the analog signal output by the air pressure sensor;
• a first microprocessing controller being connected to the amplifier, and including an A/D converter and a digital comparing controller;
• the A/D converter converting the analog signal output by the amplifier into a digital signal and outputting the digital signal to the digital comparing controller;
• the digital signal first output by the A/D converter corresponding to a tire pressure value of the tire, and being used by the digital comparing controller as a standard pressure point for the tire;
• the digital comparing controller also comparing the standard pressure point with a new digital signal, which corresponds to a new tire pressure of the tire and is output by the A/D converter after the first output digital signal;
• the digital comparing controller outputting a high pressure signal when the new digital signal is higher than the standard pressure point by a preset percentage, or outputting a low pressure signal when the new digital signal is lower than the standard pressure point by a preset percentage;
• a first light emitting element being connected to the first microprocessing controller for indicating the high pressure signal or the low pressure signal output by the first microprocessing controller;
• and
• a first power supply unit being electrically connected to the printed circuit board for supplying electric power needed by the air pressure sensor, the amplifier, the first microprocessing controller, and the first light emitting element to operate.

A tire pressure detecting method implemented using a tire pressure warning device, comprising the following steps:

• mounting the tire pressure warning device to an inflation valve on every tire of a car;
• the tire pressure warning device including a detection circuit, a first microprocessing controller of which sending a tire location ID assigned to every tire to a signal receiving circuit provided in a dashboard of the car, so that the signal receiving circuit is able to identify the tire location of every tire;
• the detection circuit also including a power supply unit for supplying electric power needed by the detection circuit to operate;
• the first microprocessing controller further detecting a tire pressure value of the corresponding tire, and using the detected tire pressure value as a standard pressure point for the tire;
• and
• the first microprocessing controller keeping detecting the tire pressure value of the corresponding tire, and a wireless RF signal representing an excessively high or an excessively low tire pressure value being transmitted to the signal receiving circuit when a new tire pressure value detected by the first microprocessing controller later is higher or lower than the standard pressure point by a preset percentage;
• and the signal receiving circuit receiving the wireless RF signal to identify the tire from where the wireless RF signal is transmitted, and then emitting a tire pressure abnormal alarm.