HeartRateMonitor

Android phone + Galaxy Watch biosignal acquisition: real Watch acceleration, continuous Green/IR/Red PPG, and supported Polar ECG/HR/RR data with SAF CSV export.

Download and version history

Install both matching 1.3.1 apps; ordered controls and safety timeout require both updated apps. These are debug APKs, not Google Play builds.

Release	Phone APK	Watch APK	Notes
1.3.1 — 2026-10-13	mobile-debug.apk	wear-debug.apk	Latest: confirmed session controls, Watch timeout, Polar startup/recovery fixes; hardware unverified.
1.3.0 — 2026-10-12	Download phone	Download Watch	Both versionCode 4. Acquisition/lifecycle, late flush, duplicate/session isolation, Polar clocks, HR/RR CSV and frame redraw repairs.
Historical debug — 2026-10-01	Previous phone APK	Previous Watch APK	Existing release preserved. Legacy transport/rates differ from 1.3.0.

All releases. Each new repair must use a new release tag; do not overwrite historical APKs.

Sensor contracts

Source	Recorded data	Rate / timestamp
Galaxy Watch native accelerometer	X/Y/Z, m/s²	Requested 25 Hz; actual elapsed-realtime sensor event time mapped to Unix ms
Samsung continuous PPG	Green, IR, Red ADC values, normal SDK status only	25 Hz each, SDK Unix ms
Polar H10 ECG	Voltage (SDK µV converted to mV), QRS markers	130 Hz; per-sample device nanoseconds, receipt-anchored Unix ms
Polar HR / optional RR	Device BPM and rrsMs	Notification-driven; receipt time, RR intervals in ms

Simultaneous continuous PPG uses a single PPG_CONTINUOUS tracker. The legacy 100 Hz IR/Red on-demand trackers cannot satisfy that continuous three-channel contract. See Samsung's mode/rate specification.

Polar ECG capability is required: Verity Sense is not an ECG source. Receipt anchoring preserves device intervals/gaps but does not prove exact Watch–phone–Polar clock synchronization. Missing sensors/capabilities remain unavailable, and empty channels contain no synthetic rows.

Use

1. Install phone and Watch APKs; pair the Watch with the phone. Phone minimum Android 9/API 28, Watch minimum Android 11/API 30. Hardware/service capability and Samsung SDK access must also be satisfied.
2. On Watch, grant Body Sensors permission and configure Samsung Health Sensor service/SDK access for the application's package/signature. Native motion does not depend on Samsung PPG readiness.
3. On phone, grant required Bluetooth/location permissions, enable Bluetooth, and enter a Polar device ID if recording that device.
4. Choose a data directory through the system SAF picker.
5. Start; optionally pause/resume. PPG status controls include/exclude channels in the active session. HR still records if the device has no ECG.
6. Stop, then Save All or select ECG, PPG, acceleration, or Polar HR/RR export. Pending final Watch batches remain ingestible. If you select Save partial, Watch CSV metadata records watch_transfer_complete=false.
7. Wait for Watch Pause/End confirmation. Offline requests stay pending; an unreachable controller makes updated Watch software pause after 15 seconds. Active sessions send a heartbeat every 3 seconds. After Watch Activity recreation, End and start a new session; old-session Start is rejected.
8. Polar pending startup is canceled by disconnecting. Resume reconnects; ECG requires readiness, waits for asynchronous stop, and retries transient errors at most twice. Final/unsupported errors require explicit Resume or restart. HR notifications while paused/stopped are ignored, not recorded.

CSV timestamps use Unix milliseconds. Acceleration metadata preserves the nominal/requested rate; actual timestamps determine achieved rate. Export includes only received samples. Data buffers are in memory; save before closing the Activity. Plot setup refresh preserves recorded samples. Restarting Polar or changing its ID ends the current session before replacing the connection.

Build and verify

JDK 17, Android SDK platform 34, Build Tools 34.0.0. Tooling: Gradle 8.6, AGP 8.4.0, Kotlin 2.1.0; Polar SDK 4.0.0. Set JAVA_HOME to your JDK 17 installation. Android Studio Jellyfish or newer can use the same Gradle/JDK configuration.

Place the privately supplied Samsung Health Sensor SDK 1.4.1 AAR in wear/libs/. It is ignored and is never a release asset or source commit. See Samsung SDK overview/setup. Do not substitute synthetic trackers if the SDK/device is unavailable.

.\gradlew.bat :shared:test :mobile:testDebugUnitTest :wear:testDebugUnitTest :mobile:lintDebug :wear:lintDebug :mobile:assembleDebug :wear:assembleDebug :mobile:assembleDebugAndroidTest --no-daemon --console=plain
.\gradlew.bat :mobile:connectedDebugAndroidTest --no-daemon --console=plain

Outputs: mobile/build/outputs/apk/debug/mobile-debug.apk and wear/build/outputs/apk/debug/wear-debug.apk. Public CI checks shared/phone tests, phone lint and phone build. Full Wear checks require the local private SDK and are required before each release.

The merged source also retains main privacy controls: disabled backup/device transfer, private services/settings, reduced Bluetooth/location permissions and no raw signal/device-ID logs. Source changes are reviewed through a PR with merge commit. Main/Fix-issue merge audit.

Before publishing source, run the artifact/history policy and a redacted Gitleaks scan. CI runs these gates on main, Fix-issue and PRs, using pinned actions/checksums and a read-only token. Private AARs/APKs/keys/raw CSVs must stay untracked; existing release APKs are assets, not source files.

python -m unittest discover -s scripts -p 'test_*.py'
python scripts/check_publication.py --base origin/main

The old Polar SDK AAR remains in pre-existing Git history; this merge introduces no AAR. Existing tags/releases are preserved. The v1.3.1 download is the immutable previous release; merged-source verification is recorded separately in the audit.

Software checks and warning counts: session repair plan/evidence. Galaxy Watch and Polar physical sensor/session acceptance is unverified for this release: those devices were unavailable during this repair. Phone instrumentation verifies controls/service/frame scheduling, not sensor accuracy.

Complete feature specification and agent guide. BDD sensor specification.