Recipe: Core Motion Basics

The Core Motion framework centralizes motion data processing. Introduced in the iOS 4 SDK, Core Motion supersedes the direct accelerometer access you’ve just read about. It provides centralized monitoring of three key onboard sensors. These sensors are composed of the gyroscope, which measures device rotation, the magnetometer, which provides a way to measure compass bearings, and the accelerometer, which detects gravitational changes along three axes. A fourth entry point called “device motion” combines all three of these sensors into a single monitoring system.

Core Motion uses raw values from these sensors to create readable measurements, primarily in the form of force vectors. Measurable items include the following properties: