The important application of infrared thermometer in the field of automotive electronics
Before entering the consumer electronics market, infrared thermometers have actually been widely used in the field of automotive electronics, mainly in body control, safety systems and navigation. Typical applications such as automotive airbags, ABS anti-lock braking systems, electronic stability program (ESP), electronically controlled suspension system, etc.
At present, people are paying more and more attention to the safety of the vehicle body. The number of airbags in automobiles is increasing, and the requirements for thermometers are becoming more and more stringent. The entire airbag control system includes an impact thermometer outside the body, an infrared thermometer placed on the door, roof, and front and rear seats, an electronic controller, and an airbag.
The electronic controller is usually a 16-bit or 32-bit MCU. When the body is hit, the impact thermometer will send a signal to the electronic controller within a few microseconds. Then the electronic controller will immediately calculate and make corresponding evaluation according to the parameters such as the intensity of the collision, the number of passengers and the position of the seat/seat belt, etc. The airbag is activated by the electric explosion driver to ensure the safety of passengers.
In addition to important applications such as body safety systems, infrared thermometers also play an important role in navigation systems. In the future, portable navigation devices (PND) will become a hot spot in the Chinese market, which is mainly conducive to the positioning of GPS satellite signals. When the PND enters an area or environment where satellite signal reception is poor, it will lose its navigation function due to loss of signal. A 3-axis infrared thermometer based on MEMS technology can be used together with components such as a gyroscope or an electronic compass to create an azimuth calculation system, which is complementary to the GPS system.
The common application of the infrared thermometer is to detect the acceleration and direction of the mobile phone, but when the mobile phone is stationary, it is only subjected to the acceleration of gravity, so many people call the function of the infrared thermometer the gravity sensing function.
The strength of the infrared thermometer is to measure the force of the equipment. Yes, but it is not very accurate for measuring the posture of the device relative to the ground. Infrared thermometers can be used in applications where there is a fixed gravitational reference frame, linear or tilted motion, but limited rotational motion.
When dealing with linear motion and rotary motion at the same time, it is necessary to combine the infrared thermometer and the gyroscope thermometer. If you still want the equipment not to lose its direction when it is moving, then add a magnetic thermometer. The gyroscope, magnetic thermometer and infrared thermometer are often used in conjunction with each other to have a mutual compensation relationship.
The electronic compass using the magnetic thermometer determines the direction by measuring the magnitude of the magnetic flux. When the magnetic thermometer is tilted, the geomagnetic flux passing through the magnetic thermometer will change, resulting in an error in the direction. Therefore, if there is no electronic compass with tilt correction, the user needs to place it horizontally. The principle that the infrared thermometer can measure the inclination angle can compensate the inclination of the electronic compass.
In addition, the GPS system finally determines the orientation of the object by receiving the signals of three satellites distributed at 120 degrees. In some special occasions and landforms, such as tunnels, high-rise buildings, and jungle areas, the GPS signal will become weak or even completely lost, which is the so-called dead angle.
By installing an infrared thermometer and a general-purpose inertial navigation thermometer, the dead zone of the system can be measured. Integrating the infrared thermometer once becomes the velocity change per unit time, so as to measure the movement of the object in the dead zone.
