What Is a 3-Axis Accelerometer?

Current acceleration sensors have multiple implementations, which can be divided into three types: piezoelectric, capacitive, and thermal induction. According to the number of input shafts, there are uniaxial, biaxial, and triaxial accelerometers.

In space vehicle

Most of the current three-axis acceleration sensors use piezoresistive, piezoelectric, and capacitive working principles. The acceleration generated is proportional to changes in resistance, voltage, and capacitance, and is collected through corresponding amplification and filtering circuits. This is based on the same principle as ordinary acceleration sensors, so in a certain technology three single axes can be turned into a three axis. For most sensor applications, two-axis acceleration sensors can already satisfy most applications. However, some applications are still concentrated in three-axis acceleration sensors such as data mining equipment, valuable asset monitoring, collision monitoring, measuring building vibration, fans,

The advantage of the three-axis acceleration sensor is that when the direction of the object's movement is not known in advance, only a three-dimensional acceleration sensor is used to detect the acceleration signal. The three-dimensional acceleration sensor has the characteristics of small size and light weight, can measure spatial acceleration, and can fully and accurately reflect the motion properties of objects.

Applications in body safety, control and navigation systems

Before entering the consumer electronics market, acceleration sensors have actually been widely used in the automotive electronics field, mainly focusing on body control, safety systems and navigation. Typical applications such as automotive airbags, ABS anti-lock braking systems, electronic stability programs, Electronically controlled suspension systems, etc. At present, more and more attention is paid to body safety, the number of airbags in automobiles is increasing, and the corresponding requirements for sensors are becoming stricter. The entire airbag control system includes shock sensors outside the vehicle body, acceleration sensors placed on the door, roof, and front and rear seats, electronic controllers, and airbags. The electronic controller is usually a 16-bit or 32-bit MCU. When the body is hit, the impact sensor sends a signal to the electronic controller within a few microseconds. Then the electronic controller will immediately calculate and make corresponding assessments based on the parameters of the collision intensity, the number of passengers, and the position of the seat / belt, and the data returned by the sensors distributed throughout the compartment, and pass in the shortest time The electric explosion driver activates the airbag to ensure the safety of passengers.

In addition to important applications such as body safety systems, acceleration sensors currently play an important role in navigation systems. Experts predict that portable navigation devices (PND) will become a hot spot in the Chinese market, which is mainly conducive to GPS satellite signals for positioning. When the PND enters an area or environment with poor satellite signal reception, the navigation function will be lost due to the loss of the signal. A three-axis acceleration sensor based on MEMS technology, combined with components such as a gyroscope or electronic compass, can create an azimuth estimation system, enabling complementary applications to GPS systems.

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 laptops, mobile phones, digital cameras / camcorders, portable DVD players, PMPs and other devices. Because of its application occasions, portable devices often fall accidentally or are impacted, which causes a huge impact on internal components.

In order to protect the device and its data from damage, more and more users have demanded the impact resistance of portable devices. The drop height of general portable products is 1.2 ~ 1.3 meters, and it will be impacted by about 50KG when it hits the marble floor. Although a good cushioning design can be used to break down most of the impact force from the equipment case or PCB board, high-speed rotating devices such as hard disks are very vulnerable to such impacts. If a 3-axis acceleration sensor is built into the hard disk, when a drop occurs, the system will detect a sudden change in acceleration and perform corresponding self-protection operations, such as turning off electronic or mechanical devices with poor anti-vibration performance to avoid damage, or Hard disk head damage or scratches may cause permanent data loss.

Innovative applications in consumer products

The three-axis acceleration sensor enables revolutionary innovation for traditional consumer and handheld electronic devices. It can be installed on the handle of a game console, and acts as a user motion collector to sense the movements of its arms back and forth, left and right, and up and down, etc., and transform into virtual scene actions such as punching, racket, jumping, throwing Fishing rods, etc., turn simple finger movements into real limb and body movements to achieve a sense of on-site gameplay and participation that could not be achieved with conventional key operations.