This app is available for free. If you find it useful or like it, please buy me a cup of coffee. https://buymeacoffee.com/alex.kim Sensor Lab turns the sensors inside your watch into live, moving pictures that follow the real measurements. • Heartbeat – a 3D heart beats lub-dub on every real beat, inside your heart-rate zone gauge (from your watch profile), with a rhythm row of the last 6 seconds. • Beat interval (RR) – a pulse line whose peak spacing and height follow your real beat-to-beat intervals, with each interval in ms and RMSSD. Turns grey when no intervals arrive. • Motion – accelerometer and gyroscope gauge: movement with gravity removed, Twist / Tilt / Turn rotation bars, and a Still / Moving / Active state. Handy for checking you are still before an HRV measurement. • Compass – a compass rose that turns with your heading; the red needle always points north. • Air & altitude – an aurora that moves with pressure and altitude changes (stairs, lifts), with altitude and pressure change per minute. • Bubble level – round and tube bubble vials; turns green and vibrates when level within 1°. Also: pages appear only for sensors your watch has, help with diagrams and tables for every page, English and Korean, and the screen stays as it is in Always On mode. Notes: Beat intervals need a temporary activity session, which is never saved. On the first launch they may take a while to arrive. Not a medical device; for wellness and curiosity only.