Читать книгу Apple Watch For Dummies - Marc Saltzman - Страница 40

On the back of Apple Watch, as shown in Figure 1-11, are multiple sensors to monitor your heart rate, blood-oxygen level, and more. In fact, the addition of blood-oxygen monitoring beginning with Apple Watch Series 6 changed the back crystal underneath the watch; now it’s made up of four LED clusters and four photodiodes. See Chapter 2 for more on the sensors and the charger.

FIGURE 1-11: The sensors on the back of Apple Watch can, among other things, calculate your heart rate and measure your blood-oxygen percentage.