Fitness trackers and smart watches are gradually becoming An essential lifestyle device that can help us track our own activity level and basic health parameters. In fact, in order to help people measure activity levels and heart health, there are many technologies in those tiny devices that are worn on the wrist.

Any typical fitness bracelet or smart watch has about 16 sensors built in. Depending on the price, the quantity of some products may increase. These sensors and other hardware components (such as batteries, microphones, displays, speakers, etc.) and powerful high-end software form a fitness tracker or smart watch.

1. The ambient light sensor can adjust the display brightness

Most fitness trackers and smart watches are equipped with ambient light sensors. Its main job is to adjust the brightness of the display according to the surrounding light. This also helps to save battery life.

2, three-axis accelerometer detects movement and tracks direction

The three-axis accelerometer is the most common sensor in wearable devices . The sensor can track forward and backward movement, sense gravity and determine the body's direction, position, and rate of change of speed.

3. The altimeter can detect your climbing height

The altimeter can detect changes in height. It helps to detect whether you are climbing stairs or downhill, so it helps to measure calories.

4. The optical heart rate sensor can detect heartbeats per minute

Almost every fitness tracker is equipped with an optical heart rate sensor, which uses light to check the blood flow rate on the wrist to calculate the number of heart beats per minute. When the heart beats, blood flows quickly in the arteries, so less light is reflected on the sensor and it is detected as a heart beat.

5, SpO2 monitor can measure the oxygen content in the blood

The sensor checks the color of the blood to understand the oxygen content in it. Fitbit explained: "The deoxygenated blood that flows back into the lungs through the veins is slightly more red than the fully oxygenated blood in the arteries. The sensor measures the relative reflectivity of red light and infrared light in the blood through the wrist, and estimates the SpO2 value by observing the changes in the heartbeat. ”

6. The bioimpedance sensor can measure breathing rate, sleep, etc.

The bioimpedance sensor measures the resistance of the skin to a small amount of electricity. The battery charger electrode in the fitness tracker can provide a very small amount of current to measure sleep, heart rate, breathing rate, water level, etc.

7, the proximity sensor can save battery and wake up the display when needed

The proximity sensor just lets the device know that you are near the device and want to use it. If you are not wearing a fitness tracker, this sensor can put the device to sleep when not in use and save battery power. It is mainly used to open or close the display.

8. Compass to help directions and maps

The compass helps the Map application run on the smart watch and provides a sense of direction for the device.

9, ECG sensor

ECG sensor is a new feature of wearable devices. Now, the role of this sensor is to detect the tiny electrical impulses emitted by your heart every time your heart beats. Now, the job of this sensor is to detect the tiny electrical impulses that your heart sends out with every heartbeat. This sensor detects this minute's heart signal through electrodes on the wearable device.

10. Global Positioning System

GPS can only help you detect the amount of running, the location of the wearable device and track your activity. It also helps guide the Map application.

11, gyroscope

Technically speaking, gyroscopes measure the angular velocities used to detect movements and accurately track them during the journey. For example, data from gyroscopes and other sensors can determine whether you are actually running or jogging somewhere. In addition, it can also eliminate the movement caused by severe wrist shaking and mistake it for vigorous running.

12. Gesture sensor detects wrist movement

When the hand is moved in a certain way, the gesture sensor can instruct the smartwatch to perform certain activities. For example, if the wrist is flicked twice, the call will be disconnected, or the stopwatch will start timing when the hand ring rotates. It is the job of the gesture sensor to detect these pre-feed actions.

13. UV sensors can measure exposure to harmful sunlight

Some smart watches also provide information on whether outdoor sunlight is harmful. This is detected by the ultraviolet sensor, and when you go outside, the ultraviolet sensor detects ultraviolet rays.

14, Magnetometer Magnetometer

Work with GPS and compass to determine the exact coordinates of your location.

15. Galvanic skin activity sensor

Skin activity or EDA sensors are new features of wearable devices. It measures pressure with a heart rate tracker, ECG and skin temperature sensor. It can detect subtle electronic changes in skin sweat and help you relieve stress.

16. Skin temperature sensor

The skin temperature sensor detects slight changes in temperature to see if you will get sick like a fever or detect the start of your menstrual period.