Accelerometer and Gyroscope
You can use accelerometer and gyroscope data to deliver real-time information in your app. For example, you can use motion data to gauge the wearer’s activity level and track specific types of movement, such as arm movements made during a workout. Apple Watch also lets you access sensor data for longer periods of time so that you can identify long-term movement patterns.
Use motion data only to offer a tangible benefit to people. For example, fitness apps use the data to provide feedback about people’s activity and general health. Don’t gather data simply to have the data.
Avoid using the accelerometers or gyroscopes for the direct manipulation of your app’s interface. Some motion-based gestures may be difficult to replicate precisely, may be physically challenging for some people to perform, and may cause the screen to dim. Touch events, gestures, and the Digital Crown give people more precise ways to interact with your interface.