With the advancement of technology, the mobile phone is no longer a simple communication tool, but a portable electronic device with comprehensive functions. Do you know the principles and uses of common sensors in mobile phones?
1. Geomagnetic sensor
The smartphone compass function uses the geomagnetic field and the phone’s built-in geomagnetic sensor to achieve geographic orientation. The direction of the compass pointer changes, indicating that the geomagnetic field and the phone’s built-in communication chamber sensor have worked, but the direction is opposite. This situation may be affected. It is caused by the interference of strong external magnetic field, such as a strong magnetic field in a certain location, or other external factors opposite to the earth's magnetic field, which may cause the influence of this magnetic field. When climbing, you can change a position or move the phone horizontally in a figure 8 to calibrate the compass.
2. Gyroscope
Principle: Conservation of angular momentum. When an object (gyro) is rotating at a high speed, its axis of rotation will not be affected by external forces, and the direction of the axis of rotation will not change. The gyroscope is based on this principle and uses it to maintain a certain direction. The three-axis gyroscope can replace three single-axis gyroscopes, and can measure the position, movement trajectory and acceleration in 6 directions at the same time.
Uses: somatosensory, shaking (shaking the phone to achieve some functions), pan/turn/mobile phone can control the viewing angle in the game, VR virtual reality, inertial navigation according to the motion state of the object when there is no GPS signal (such as in a tunnel).
3. Light sensor
Principle: The photosensitive triode, when receiving external light, will generate currents of varying strength, thereby perceiving the brightness of the environment.
Purpose: Usually used to adjust the brightness of the screen's automatic backlight, increase the screen brightness during the day, and reduce the screen brightness at night, so that the screen can be seen more clearly without glare. It can also be used for automatic white balance when taking pictures. It can also be used with the distance sensor below to detect whether the phone is in the pocket to prevent accidental touch.
4. Distance sensor
Principle: The infrared LED lamp emits infrared light, and after being reflected by a close object, the infrared detector measures the distance by receiving the intensity of the infrared light. Generally, the effective distance is within 10cm. The distance sensor has both transmitting and receiving devices, and is generally large in size.
Purpose: To detect whether the mobile phone is attached to the ear and is making a call, so as to automatically turn off the screen to save power. It can also be used to automatically unlock and lock the screen in leather case and pocket mode.
5. Gravity sensor
Principle: It is realized by the piezoelectric effect. A weight and piezoelectric sheet inside the sensor are integrated together, and the horizontal direction is calculated by the voltage generated in two orthogonal directions.
Purpose: Smart switching of mobile phone horizontal and vertical screens, camera orientation, gravity-sensing games (such as rolling steel balls).
6. Acceleration sensor
Principle: Same as a gravity sensor, it is also a piezoelectric effect. The acceleration direction is determined through three dimensions, but the power consumption is smaller, but the accuracy is low.
Uses: pedometer, mobile phone placement position facing angle.
7. Magnetic field sensor
Principle: The anisotropic magnetoresistive material will cause its own resistance to change when it feels a weak magnetic field, so the phone needs to rotate or shake a few times to accurately indicate the direction.
The utility model provides a scanner capable of scanning one-dimensional and two-dimensional barcodes, comprising: a casing and a scanning device, a start button is arranged on the casing, the scanning device is provided with a circuit board, and the circuit board carries a microcomputer A control processing module, an image capture module, and a laser light module; and the key point of the present invention is that the laser light module can emit a linear laser light and project it on a barcode, and the linear laser light is used as an indicator light (pointer). ), but when the scanning device wants to read the barcode, immediately turn off the linear laser light so as not to cause interference and affect the reading efficiency of the scanner.
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