|Light Weight: Weighing in at only 30 grams, the SmarTire sensor uses a lightweight Dupont polymer containing only 13 to 15 percent glass fiber by weight. Other plastics have a glass content of up to 35 percent.|
Relax and drive. You no longer have to step out of the car to check if your tires are properly inflated. SmarTire has just introduced a new low-cost tire sensor weighing only 30 gm. Being lightweight is an asset to parts inside a tire that have to survive heavy spinloads produced by centrifugal forces up to 3,000 times gravity. What's more, lightweight sensors do not affect the balance of the wheel or the handling of the vehicle.
The secret to the sensor's light weight is a Dupont polymer containing only 13 to 15 percent glass fiber by weight. Glass fibers make a part heavier because they have more than double the specific gravity of typical engineering plastics. They can also interfere with the RF signals the sensor uses to transmit data from inside the tire. DuPont Zytel HTN54G15HSL is used for the sensor's support cradle and housing body component. The housing body's cover is molded from Zytel 71G13HS1L nylon.
The SmarTire system consists of two parts: a wireless sensor/transmitter that mounts inside each of the tires via a stainless steel strap that goes around the wheel rim and a receiver/LCD unit that goes in the vehicle. The sensor monitors the air temperature and pressure continuously. When the vehicle starts rolling, a centrifugal switch activates the sensor, which wirelessly transmits the initial tire information to the receiver inside the vehicle. The sensor reads the data every 12 sec and transmits the tire pressure and temperature nominally every 4 min. If the tire pressure increases or decreases by 3 psi, the sensor transmits the significant change immediately. When tire pressure gets too low or tire temperature gets too high, a bright red LED light and an audible alert gets activated.
Based in British Columbia, Canada, SmarTire supplies tire pressure monitoring systems for passenger cars, motorcycles, and recreational vehicles.