The Sensors of Smartwatches

2023-09-15 15:09:09

Smartwatches are commonly used among young people. With so many functions mixed in a little device, people are getting more reliable on a smartwatch by wearing it in many different situations. Counting how many steps you are walking, making payment transactions, or even checking your physical health could all be achieved by a smartwatch. These amazing features are proceeded by the sensor, which is available in most smartwatch models such as watch gt4. In this article, we would like to go deeply into the powerful sensors of a smartwatch.


Sensors: The Spirit of a Smartwatch

With the advancement in technology, there are now more smartwatch sensor technologies available every year. In this section, we will introduce a few common and several newly emerged sensor technologies. 

 

Acceleration Sensors for Exercise Pedometer 

Simply put, gravity acceleration sensors detect acceleration and transform it into an electrical signal, which is then used to calculate the number of steps taken, the distance traveled, and the number of calories burned. Typically, it makes use of Hall, GMR, TMR, and particular algorithms. 

Optical Heart Rate Sensor and Bioelectrical Impedance Sensor for Heart Rate Detection

The most popular optical heart rate sensor, which was also one of the first sensors used in smart bracelets, works by illuminating the skin and nearby blood vessels with green LED light, which is then measured to determine how much light is being absorbed by changes in heart rate. This technology is used for auxiliary sports detection as well as for the early detection of cardiac anomalies. In addition, through the biological muscle's own impedance, the bioelectrical impedance sensor can monitor blood flow and translate it into a specific heart rate, respiration rate, and dermato-electric response index. As it combines different types of data, detection accuracy is improved and information is meaningful.

Sleep Monitoring: Via Three Different Methods

Firstly, simple sleep monitoring also uses an acceleration sensor to determine whether you are asleep. This method's basic principle is that people sleep less and move less frequently, making it difficult to detect when they are sleeping. While this method does have a certain degree of accuracy, it is also simple to make mistakes. For instance, if you maintain the same position in the quilt while using the phone, using this method of detection may also result in false positives. Secondly, the heart rate sensor is used to determine the sleep state. The HRV heart rate variability detection is completed using the PPG photoelectric volumetric pulse wave tracing method, which has higher accuracy than a pure acceleration sensor. Thirdly, the CPC analysis would detect the sleep situation. The basic idea behind this type of analysis is to use the coupling relationship between the heart and the lungs to determine a person's overall wakefulness, light sleep, and deep sleep states. For the time being, this solution is more accurate and can also lower the rate of incorrect judgments made when a user is ill, or when they are slightly below the stated state of continuous stillness but have not yet fallen asleep. However, high-level smart wearable products frequently have this type of program, so cheap, basic smartwatches won't have it.


Conclusion

In conclusion, the sensor is the core of smartwatches by bringing them incredible functions. Dividing by different technologies, sensors allow smartwatches to complete multiple complex tasks. For instance, the acceleration sensors for exercise pedometers benefit the users by showing their physical situation. Moreover, the optical heart rate sensor and bioelectrical impedance sensor will detect the heart rates, respiration rate, and dermato-electric response index that are useful. Finally, by monitoring the sleep situation by 3 methods, users could understand the sleeping quality and reduce the chance to get sick.