As technology has evolved, people have been searching for ways to make their lives easier with the help of “smart devices”. Doctors are starting to use automated blood pressure machines rather than the traditional sphygmomanometer and online services to record data for their patients. Major tech companies like Apple and Google eventually came up with smartwatches: small watch-like devices that can monitor and measure people’s health all while looking like a watch. This begs the question:

How do smartwatches work so effectively?

Samsung’s new watches, the Galaxy Watch4 and Galaxy Watch4 Classic have many sensors that enable it to perform its functions. Here are the sensors and their functions:

Accelerometer: The accelerometer pretty much measures the speeding up or slowing down of your wrist. The watch can use the acceleration it measures to determine what you are doing with your hands, such as clapping, petting, or even using a remote. The accelerometer is most useful to measure steps by recording the changes in the repeated swinging motion of the arm.

Barometer: Barometers measure pressure. It is a general rule that pressure decreases at higher elevations. Your smartwatch can detect variations in pressure to calculate your altitude and display data in various exercises such as hiking and climbing.

Gyro Sensor: The gyro sensor can be used to measure the watch’s orientation and determine if the watch is facing upward. Through personal testing, I have concluded that the watch screen only turns on when the watch’s screen is facing close to upward (because it is assuming your wrist is below your face when you are looking at it). The gyro sensor can also cooperate with the accelerometer to determine what actions you are doing.

Geomagnetic Sensor: The geomagnetic sensor can measure the magnetic field of the Earth. Many compasses contain this sensor. The Galaxy Watch4 comes with a built-in compass app, and this sensor is most likely used when the app is opened.

Optical Heart Rate Sensor: Almost every smartwatch comes with an optical heart rate sensor that is usually on the back of the watch. The optical heart rate sensor flashes a bright light into the skin. The skin and blood reflects this light and a photodetector measures this refracted light. The measure of refracted light can determine the heart rate. If you own a smartwatch such as the Apple Watch, you will most likely notice that if you take the watch off abruptly, a green or red light will be flashing.

All these sensors enable the Galaxy Watch4 to give accurate and precise data that allows all of us to monitor our health without the hassle of continuously going to the doctor.