Lockstep Previous track Play or pause Next track Playback Now playing controls while Lockstep runs Previous Next Play or pause Loading playlist… Welcome to Lockstep Lockstep shows playback controls in a notification while you run. Grant notification permission so controls stay visible. Continue and ask for notification permission Sign in with Spotify via the Lockstep web login. When your browser returns to this app, your access token is stored locally. Open Spotify login Account linked — you can continue. Continue Continue without Spotify for now Playlists Tap to play (or pair local MP3s) Settings More controls will land here in a later milestone. Sign out of Spotify Clears your stored access token and returns to the welcome steps so you can log in again. Use this if the app gets HTTP 401 from the server. Annotation mode When enabled, choosing a playlist opens beat annotation (tap in time) instead of Now playing. Collect run data When enabled, Now playing records accelerometer, gyroscope, and GPS (1 Hz) per song into Documents/Lockstep/ under a timestamped run folder. Beat annotation Tap on each beat; times use the same clock as playback (ExoPlayer position). Tap here on the beat Beats recorded: %1$d %1$d ms Pair local MP3s Choose folder of MP3s Scan audio on this device Finds MP3s in Music and other folders without using the folder picker. Audio permission is required to scan MP3s on this device. Paired with local file Not paired — tap to pick an MP3 No MP3 files found in that folder. No tracks loaded for this playlist yet. Open Playlists and wait for sync, then try again. Tracks appear but have no Spotify id (removed items or sync issue). See LockstepPairing logs. Paired %1$d track(s). Paired %1$d track(s); %2$d still unmatched or unreadable. (removed or unknown track) Now playing No track yet — Step frequency --