What sensors does the phone have?

Nowadays, everyone’s life is inseparable from mobile phones. You can control the direction of a racing car by shaking your mobile phone. When you take a walk on the playground with your mobile phone, it can record how many kilometers you have walked. These scenes that you are becoming more and more familiar with are indispensable by your side every day. smartphone. The mobile phone can accomplish the above tasks mainly by relying on the sensors installed inside. Do you know how many types of sensors there are in mobile phones? And what principles do they rely on to operate?!

1. Ambient Light Sensor

The light sensor is similar to the eyes of your phone. The human eye can adjust the light entering the eye in different light environments. For example, when entering a movie theater, the pupil will dilate to allow more light to enter the eye. The light sensor allows the mobile phone to sense the intensity of ambient light and use it to adjust the brightness of the mobile phone screen. And because the screen is usually the most power-consuming part of a mobile phone, using a light sensor to help adjust the screen brightness can further extend battery life. The light sensor can also be used in conjunction with other sensors to detect whether the phone is placed in a pocket to prevent accidental touches.

2. Proximity sensor

Infrared rays are emitted through the infrared LED light, which is reflected by the object and received by the infrared detector. This is used to judge the intensity of the received infrared rays to determine the distance. The effective distance is about 10 meters. It can sense whether the phone is placed against the ear to talk on the phone, and if so, it will turn off the screen to save power; the distance sensor can also be used in the glove mode supported by some mobile phones to unlock or lock the phone.

3. G-Sensor

This is achieved through the piezoelectric effect. There is a weight inside the gravity sensor integrated with the piezoelectric film, and the horizontal direction is calculated through the voltage generated in two orthogonal directions. When used in a mobile phone, it can be used to switch between horizontal and vertical screen orientations. When used in a racing game, the data can be used in the game to rotate the driving direction through horizontal sensing.

4. Accelerometer Sensor

The working principle is the same as the gravity sensor, but the acceleration direction is determined through three dimensions, with low power consumption but low accuracy. It can be used in mobile phones to count steps and determine the direction of the mobile phone.

5. Magnetism Sensor

Measure the change in resistance to determine the magnetic field strength. When using it, you need to shake the phone to accurately judge. It is mostly used in compasses and map navigation.

6. Gyroscope

Gyroscopes are capable of measuring angular velocity along one or several axes and are an ideal technology to complement the functionality of MEMS accelerometers (acceleration sensors). In fact, by combining the two sensors, accelerometers and gyroscopes, system designers can track and capture complete motion in 3D space, providing end users with a more realistic user experience, accurate navigation systems and other features. The "shake" function in mobile phones (for example, shake the phone to draw lots...), somatosensory technology, and VR perspective adjustment and detection all use gyroscopes.

7. GPS

There are 24 GPS satellites operating in specific orbits above the earth. They will constantly broadcast their position coordinates and timestamps (timestamp, refers to Greenwich, January 1, 1970, 00 00 minutes and 00 seconds to the present) to all parts of the world. (the total number of seconds until), the GPS module in the mobile phone starts from the instantaneous position of the satellite, and calculates the distance between the mobile phone and the satellite based on the time difference between the timestamp of the satellite's transmission coordinates and the time of reception. It can be used for positioning, speed measurement, distance measurement and navigation.

8. Fingerprint sensor

The current mainstream technology is capacitive fingerprint sensor, but ultrasonic fingerprint sensor is also gradually becoming popular. When the capacitive fingerprint sensor works, the finger is one pole of the capacitor and the other pole is the silicon chip array. Through the micro current generated between the micro electric field of the human body and the capacitive sensor, the peaks and troughs of the fingerprint and the sensor are connected. The distance forms a difference in capacitance height to depict the pattern of the fingerprint. The principle of the ultrasonic fingerprint sensor is similar, but it will not be interfered by sweat or oil, and the recognition speed is also faster. It can be used on mobile phones to unlock, encrypt, pay, etc.

9. Hall Sensor

The principle of action is the Hall magnetoelectric effect. When a current passes through a conductor located in a magnetic field, the magnetic field will exert a force perpendicular to the direction of electron movement on the electrons in the conductor, thus generating an electric potential difference at both ends of the conductor. It is mainly used in functions such as flip unlocking and closing the cover to lock the screen. Apple's Smart cover and official mobile phone accessories of many brands all use this technology.

10. Air pressure sensor (barometer)

Connect the film to a transformer or capacitor. When the air pressure changes, the resistance or capacitance value will change, thereby measuring the air pressure data. GPS can also be used to measure altitude, but there will be an error of about 10 meters. If equipped with a barometric pressure sensor, the error can be corrected to about 1 meter; it can also be used to assist GPS positioning to confirm the location of the floor and other information. Apple's iPhone 6/6s series are equipped with air pressure sensors.

11. Heart rate sensor

When the finger is illuminated by a high-brightness LED light, the brightness (depth of the red light) changes periodically as the heart pumps blood to the capillaries. Then the camera captures these regular changes and transmits the data to the mobile phone for calculation, and then determines the contraction frequency of the heart and obtains the number of heartbeats per minute.

The Samsung Galaxy S7 edge has a heart rate sensor next to the camera.

12. Blood oxygen sensor

Hemoglobin and oxyhemoglobin in blood have different absorption ratios of red light. Use infrared light and red LED to illuminate your finger at the same time, and measure the absorption spectrum of the reflected light to measure the blood oxygen content. Can be used in sports or health applications.

13. UV sensor

The photoelectric emission effect of certain semiconductors, metals or metal compounds releases a large number of electrons under ultraviolet irradiation. The intensity of ultraviolet rays can be calculated by detecting this discharge effect. The main uses are also in the field of sports and health.

Overall, most of the first seven sensors are standard equipment for current smartphones, and fingerprint sensors are also becoming more and more popular. Sensors at the rear are more common in smart bracelets and higher-end, high-end mobile phones. Through the function of these sensors, the mobile phone can have higher functions than you and I imagined. It seems to make the mobile phone smarter and smarter, don’t you think? The above is some analysis of the sensors on the mobile phone, which will help everyone understand the mobile phone. understanding.