1. Direct tire pressure monitoring: Tire pressure monitoring device is installed in each tire using a pressure sensor to directly measure the tire pressure, the use of wireless transmitter pressure information from the tire to send to the central receiver module, The tire pressure data are then displayed. When the tire pressure is too low or leak, the system will automatically alarm.
2. Indirect tire pressure monitoring: the working principle of indirect tire pressure monitoring is: When a tire pressure is reduced, the weight of the vehicle will make the wheel rolling radius will become smaller, resulting in its speed faster than other wheels. By comparing the speed difference between the tires to achieve the purpose of monitoring tire pressure. Indirect tire alarm system is actually rely on the calculation of tire rolling radius to monitor the air pressure.
3. Tire Intelligent Monitoring System (TPMS) Description: It combines the advantages of the two systems, which in two pairs of diagonal tires equipped with a direct sensor, and equipped with a four-wheel indirect system. This hybrid system can reduce the cost and overcome the disadvantage that the indirect system can not detect a plurality of tires while the air pressure is too low, as compared with using the direct system altogether. However, it still does not provide real-time data on the actual pressure in all four tires as in a direct system.