The sensor (English name: transducer/sensor) is a detection device that can sense the measured information and can transform the sensed information into an electrical signal or other required form of information output to meet the information. Requirements for transmission, processing, storage, display, recording and control.
The characteristics of the sensor include: miniaturization, digitization, intelligence, multi-function, systemization, and networking. It is the first step in achieving automatic detection and automatic control. The existence and development of the sensor allows the object to have senses such as touch, taste and smell, and let the object slowly become alive. Generally, it is divided into ten categories according to its basic sensing function: thermal element, photosensitive element, gas sensor, force sensor, magnetosensitive sensor, humidity sensor, sound sensor, radiation sensor, color sensor and taste sensor. .
With the advancement of technology, mobile phones are no longer a simple communication tool, but a portable electronic device with integrated functions. The virtual functions of mobile phones, such as interaction and games, are realized by the powerful computing power of the processor, but the functions combined with reality are realized by sensors. This article has compiled the common sensors in mobile phones for everyone to understand their principles and uses.
First, the light sensor:
Principle: Photosensitive triodes, when receiving external light, will produce different currents of strong and weak, thus sensing the ambient light brightness.
Uses: Usually used to adjust the brightness of the screen's automatic backlight, increase the screen brightness during the day, reduce the screen brightness at night, make the screen more clear, and not 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 if the phone is in the pocket to prevent accidental touch.
Second, the distance sensor:
Principle: The infrared LED lamp emits infrared rays. After being reflected by close-range objects, the infrared detector measures the distance by receiving the intensity of the infrared rays. The general effective distance is within 10 cm. The distance sensor also has a transmitting and receiving device, which is generally bulky.
Uses: Detect whether the phone is attached to the ear and is making a call to automatically turn off the screen to save power. It can also be used in the holster and pocket mode to automatically unlock and lock the screen.
Off-topic: the position of the light sensor and the distance sensor. The light sensor and the distance sensor are usually placed together around the front earpiece of the mobile phone. This has a problem. The mobile phone has too many holes or black strips on the forehead. Looks good, so Apple has been trying to reduce the opening, or hide the hole. The black panel phone can easily hide the two sensors, but the white panel is a bit more difficult:
There are so many sensors in the phone! I finally got to know that there are so many sensors in the phone! I finally understood that Apple started from the iPhone5 and made the light sensor white. It was well hidden, but many domestic mobile phone manufacturers could not do it for a while. They can only use smaller sensors and light + distance sensors. Put them together to make a smaller strip, or a large circle as big as the camera, so it's relatively nice. The hammer's sensor is also a long strip, but it is hidden inside the earpiece.
Third, the gravity sensor:
Principle: Using the piezoelectric effect, a weight inside the sensor is integrated with the piezoelectric piece, and the horizontal direction is calculated by the magnitude of the voltage generated by the two orthogonal directions.
Uses: mobile phone horizontal and vertical screen intelligent switching, photo photo orientation, gravity sensing games (such as rolling steel balls).
Fourth, the acceleration sensor Principle: The same as the gravity sensor, but also the piezoelectric effect, the acceleration direction is determined by three dimensions, but the power consumption is smaller, but the precision is low.
Uses: Step counting, mobile phone placement position angle.
Fifth, the magnetic field sensor:
Principle: Anisotropic magnetoresistive materials, when they feel a weak magnetic field change, will cause their own resistance to change, so the phone should be rotated or shaken a few times to accurately indicate the direction.
Uses: compass, map navigation direction, metal detector APP.
Sixth, gyroscope:
Principle: Angular momentum conservation, an object that is rotating at high speed (gyro), its rotation axis is not affected by external forces, the direction of the rotation axis will not change. The gyroscope is based on this principle and is used to maintain a certain direction. The three-axis gyroscope can replace three single-axis gyroscopes to simultaneously measure position, movement trajectory and acceleration in six directions.
There are so many sensors in the phone! I finally got to know the purpose: somatosensory, shake (shake the phone to achieve some functions), pan / rotate / mobile phone can control the angle of view, VR virtual reality in the game, when the GPS has no signal (such as in the tunnel) according to the object movement The state implements inertial navigation.
Seven, GPS
Principle: There are 24 GPS satellites running in a specific orbit of the Earth. Each satellite constantly broadcasts its current position coordinates and time stamp information to the world. The mobile phone GPS module receives this information via the antenna. The chip in the GPS module uses the instantaneous position of the satellite in high-speed motion as the known starting data, calculates the distance between the satellite and the mobile phone according to the time stamp of the satellite transmitting coordinates and the time difference between the receiving, and uses the method of spatial distance resection to determine the test. The position coordinates of the point.
Uses: map, navigation, speed measurement, ranging.
Eight, fingerprint sensor:
At present, the mainstream is capacitive fingerprint recognition, but the identification of ultrasonic fingerprints with higher recognition rate and higher recognition rate will gradually become popular from this year.
Capacitive fingerprint sensor principle: the finger constitutes one pole of the capacitor, and the other pole is a silicon wafer array. The micro electric field between the human body and the capacitive sensor form a micro current, and the distance between the peak wave trough of the fingerprint and the inductor forms a capacitance difference. To draw a fingerprint image.
Ultrasonic fingerprint sensor principle: Ultrasound is mostly used to measure distance, such as sonar system for seabed topographic mapping. The principle of ultrasonic fingerprint recognition is the same, that is, direct scanning and mapping of fingerprint texture, even the pores can be mapped. Therefore, the fingerprint obtained by the ultrasonic wave is 3D stereoscopic, and the capacitive fingerprint is a 2D plane. Ultrasound not only recognizes faster speeds, but also is immune to interference from sweat and oil, and the fingerprint details are more abundant and difficult to crack.
Uses: encryption, unlocking, paying...
Nine, Hall sensor principle: Hall magnetoelectric effect, when the current passes through a conductor in the magnetic field, the magnetic field will produce a force perpendicular to the direction of electron motion of the electrons in the conductor, thus the conductor A potential difference is generated at both ends.
Uses: The flip cover is automatically unlocked, and the cover automatically locks the screen. There are so many sensors in the phone! Finally, I understand 10. Pressure sensor Principle: Divided into a variable-capacity or variable-resistance air pressure sensor, the film is connected with a varistor or a capacitor, and the pressure change causes the value of the resistor or capacitor to change, thereby obtaining the air pressure data.
Uses: GPS calculates the altitude will have an error of about ten meters, the air pressure sensor is mainly used to correct the altitude error (to about 1 meter), of course, can also be used to assist GPS to locate the overpass or floor position.
XI, heart rate sensor:
Principle: Use a high-brightness LED light source to illuminate the finger. When the heart presses fresh blood into the capillaries, the brightness (red depth) changes like a wave, and the camera automatically captures this regularly changing interval. The frequency of contraction of the heart is determined by application conversion in the mobile phone.
Uses: exercise, health.
There are so many sensors in the phone! I finally got it. 12. Blood oxygen sensor:
Principle: Hemoglobin and oxyhemoglobin in blood have different absorption ratios of infrared light and red light. The infrared light and red light are used to simultaneously illuminate the finger, and the absorption spectrum of the reflected light is measured to measure the blood oxygen content.
Uses: exercise, health.
13. UV sensor:
Principle: Using the photoelectric emission effect of certain semiconductors, metals or metal compounds, a large amount of electrons are emitted under ultraviolet irradiation, and the ultraviolet intensity can be calculated by detecting such a discharge effect.
Uses: exercise, health.
to sum up:
The first seven sensors are standard on almost every smartphone;
The eighth sensor, fingerprint identification, is now in full use. The mobile phone of six or seven hundred yuan has also begun to be standard, mainly due to the arrival of the mobile payment era, and the increase in safety and convenience requirements;
The ninth sensor, the official mobile phone or tablet that sells leather cases is generally supported;
The last four are relatively rare, mainly for outdoor, sports, health and other special user groups, more common in Samsung high-end mobile phones, in fact, in the smart watch bracelets and other products are more common.
Mobile phones are no longer a communication tool. They are simply a versatile personal assistant tool. People can't wait for mobile phones to integrate any functions. Commonly used and practical to integrate, and occasionally useful and not integrated, it is conceivable that future mobile phones will be integrated more and more. More sensors.
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