The word speed can be said to be ubiquitous in our lives. Today we will understand the working principle of acceleration sensors so that we can better use the electronic devices in our lives.
As the name suggests, an acceleration sensor is a device that can measure the acceleration of a product. There are mainly two types of accelerometers that we generally use in life, namely angular accelerometers and linear accelerometers. In life, we divide it into four categories, namely, piezoelectric acceleration sensor, piezoresistive acceleration sensor, capacitive sensor, and servo sensor.
There are two types of acceleration sensors: one is the angular acceleration sensor, which is improved by the gyroscope. The other is a linear acceleration sensor. It can also be divided into single-axis, dual-axis and three-axis acceleration sensors according to the measurement axis.
The specific application fields of acceleration sensors are mainly in the field of automotive safety, game control, automatic image flipping, electronic compass tilt correction, GPS navigation system blind compensation field, pedometer function field, anti-shake function field, flash signal function Fields, hard disk protection field, equipment or terminal attitude detection field, smart products and other fields are covered everywhere, and it can be seen that we understand the importance of the working principle of acceleration sensors.
Most of our common sensors basically have a common working principle, that is, the piezoelectric effect. By the way, we will introduce the piezoelectric effect so that everyone can better understand its working principle. The piezoelectric effect means that when certain dielectrics are deformed by external influences, polarization will occur inside the crystal, and at the same time, positive and negative charges will be generated on the surface of the crystal. When the external influence disappears, it will return to the uncharged initial state, which is the piezoelectric effect. Let's talk about several common areas where acceleration sensors are used.
Application in car body safety, control and navigation systems
Acceleration sensors have been widely used in the field of automotive electronics, mainly focusing on body control, safety systems and navigation. Typical applications are automotive airbags (Airbag), ABS anti-lock braking systems, electronic stability programs (ESP), and electronically controlled suspensions. System and so on.
At present, car body safety is getting more and more attention from people. The number of airbags in automobiles is increasing, and the requirements for sensors are becoming more and more stringent. The entire airbag control system includes an impact sensor (Satellite Sensor) outside the vehicle body, an acceleration sensor (G-Sensor) placed on the doors, roof, and front and rear seats, electronic controllers, and airbags. The electronic controller is usually a 16-bit or 32-bit MCU. When the vehicle body is impacted, the impact sensor will send a signal to the electronic controller within a few microseconds.
Then the electronic controller will immediately calculate and make corresponding evaluations according to the parameters such as the intensity of the collision, the number of passengers and the position of the seat/seat belt, and the data returned by the sensors distributed throughout the cabin, and pass it in the shortest time. The Squib Driver activates the airbag to ensure the safety of passengers.
Generally, ABS and traction control systems alone cannot meet the safety requirements of vehicles on curved roads. In this case, the electronic stability control system (ESC) can control the vehicle so that it does not deviate from the road by correcting the understeer or oversteer in the driver's operation. The system uses a gyroscope to measure the yaw angle of the vehicle and a low-gravity acceleration sensor to measure lateral acceleration. The obtained measurement data is compared with the results calculated from the two data of driving speed and wheel inclination angle, so as to adjust the steering of the vehicle to prevent sideslip.
In addition to important applications such as body safety systems, acceleration sensors are currently playing an important role in navigation systems. It is mainly conducive to GPS satellite signals to achieve positioning. When entering an area or environment with poor satellite signal reception, such as tunnels, tall buildings, or jungle areas, the navigation function will be lost due to loss of signal. A 3-axis acceleration sensor based on MEMS technology can be used with components such as a gyroscope or an electronic compass to create a dead reckoning system (DR, Dead Reckoning) to achieve complementary applications to the GPS system.
Application of MEMS acceleration sensor in medical wearable equipment
With the development of wearable smart devices, especially medical wearable smart devices, it mainly relies on the use of various miniaturized MEMS gyroscopes, acceleration sensors, etc., to detect various information about the wearer's body. For example, the application of MEMS sensors in non-invasive fetal heart detection.
Detecting the fetal heart rate is a very technical task. Because the fetal heart rate is very fast, between 120 and 160 beats per minute, it is difficult to measure accurately with a traditional stethoscope or even an ultrasound Doppler with only amplification. . In addition, ultrasonic vibration waves act on the fetus, which will have a great adverse effect on the fetus. Although the detection dose is very low, it also belongs to the category of destructive detection and is not suitable for frequent and repetitive inspections and home use.
At this time, the MEMS acceleration sensor can provide a non-invasive fetal heart detection method, and develop a simple, easy-to-learn, intuitive and accurate clinical diagnosis and pregnant woman self-check between the fetal heart stethoscope and the Doppler fetal monitor. Medical auxiliary equipment.
The fetal heart rate is converted into an analog voltage signal through the acceleration sensor, and the difference is amplified by the instrument amplifier for pre-amplification. Then a series of intermediate signal processing such as filtering is performed, and the analog voltage signal is converted into a digital signal with an A/D converter. Input to the single-chip microcomputer through the optical isolation device for analysis and processing, and finally output the processing result.
Hard disk impact protection
At present, due to the storage requirements of massive data, components such as hard disks and optical drives are widely used in notebook computers, mobile phones, digital cameras/camcorders, portable DVD players, PMPs and other equipment. Due to its application occasions, portable devices are often accidentally dropped or bumped, causing huge impact on internal components.
In order to protect the device and its data from damage, more and more users have put forward requirements for the impact resistance of portable devices.
Generally, the drop height of portable products is 1.2~1.3 meters. When they hit the marble floor, they will receive an impact of about 50KG. High-speed rotating devices such as hard disks are very fragile under such impacts.
If a 3-axis acceleration sensor is built into the hard disk, when a drop occurs, the system will detect sudden changes in acceleration and perform corresponding self-protection operations, such as turning off electronic or mechanical devices with poor shock resistance and resetting the head to reduce the hard disk The degree of damage.
Fork Type Terminals,Insulated Bullet Sockets Terminals,Insulated Bullet Terminals,Type Fork Insulate Terminal
Taixing Longyi Terminals Co.,Ltd. , https://www.longyiterminals.com