I. Which mobile phone functions are related to sensors?
For many people, mobile phones are now indispensable. Whether it's answering calls or unlocking the phone with a fingerprint, these are common functions on mobile phones. The implementation of these functions is related to sensors. Let's take a look at what sensors are in mobile phones.
1. Gyroscope
Accelerometers can provide directional information, but gyroscopes are more accurate at measuring direction. A gyroscope tells you how many degrees the device has rotated and in which direction. Without a gyroscope sensor, a device cannot watch 360-degree videos, enjoy VR experiences, or even shake itself.
2. Barometric pressure sensor
While a standard GPS system can calculate your location, a barometric pressure sensor is needed to detect changes in altitude. This sensor is primarily used to correct for altitude errors and assist GPS in locating overpasses or building floors.
3. Fingerprint sensor
Fingerprint sensors: There are two types of fingerprint sensors: the older capacitive fingerprint sensor and the ultrasonic fingerprint sensor. Compared to capacitive fingerprint sensors, ultrasonic fingerprint sensors offer faster recognition speeds and are unaffected by sweat or oil. They are used in mobile phones for unlocking, encryption, payments, and more.
4. Touch sensor
A capacitive touchscreen has narrow electrodes plated on all four sides of the screen, creating a low-voltage alternating electric field within the conductor. When the screen is touched, due to the human body's electric field, a coupling capacitance is formed between the finger and the conductive layer, and the current from the four electrodes flows to the touch point.
The strength of the current is proportional to the distance between the finger and the electrode. The controller located behind the touch screen calculates the ratio and strength of the current to accurately determine the position of the touch point.
II. Sensor Orientation
Through the above introduction, you should now have a basic understanding of the sensors in mobile phones. In this section, we will mainly discuss two aspects of sensors.
Sensors have two directions. One is the integrated sensor, which is integrated with other devices and shares power input; the other is the standalone sensor. The latter is like Robinson Crusoe surviving on a desert island; it's best to survive on its own without care. Self-powered operation is the most immediate challenge.
Self-powered sensors are attracting widespread attention, as they are ideal for applications requiring remote monitoring, wireless connectivity, and continuous monitoring.
This often requires deploying energy harvesters from sensors. These micro-energy recovery systems can generate microcurrents from solar energy, vibration, and heat for their own use. In other words, a sensor is both an energy generator and an energy storage device. If an electric vehicle can be an energy storage system, why can't a small sensor?
