Wraps Apple's CoreMotion framework for reading iPhone and Apple Watch sensors: accelerometer, gyroscope, magnetometer, pedometer, and activity recognition. You get code patterns for both real-time updates and historical queries, plus the usual gotchas like needing exactly one CMMotionManager instance and remembering to add NSMotionUsageDescription to your plist. Covers the polling pattern for games, device motion fusion for attitude tracking, and the pedometer APIs for step counting and floor detection. The battery impact table is helpful since sensor update rates directly trade responsiveness for power. Solid reference if you're building fitness tracking, motion-based UI, or anything that needs to know whether the user is walking, driving, or sitting still.
npx skills add https://github.com/dpearson2699/swift-ios-skills --skill core-motion