aorti.ca
Beta. Solo-developed, actively changing, bugs expected. Please open an Issue if something breaks. Feature requests and strap test reports welcome.
Live heart rate and HRV for streams and self. Pair a chest strap, watch it in real time, stream it to OBS, or come back later and read weeks of your own data. Free, no subscription, no account required.
Hosted at aorti.ca. Android APK for 24/7 background recording available from the GitHub releases.
What you get
- Live monitor (
hr_monitor.html). Real-time HR and RMSSD, a live trace, audio alerts, posture logging, OBS-ready widget. Auto-saves every session as a CSV.
- Session viewer (
hrv_viewer.html). Month, week, day, and single-session views over every recording. HR and HRV traces, the moments they moved together, posture and sleep windows. Multiple sessions on the same day stitch into a single day timeline.
- OBS overlay (
overlay.html). Browser-source companion to the monitor. Chroma-key ready. Uses a broadcast key so one phone or laptop can publish and any OBS instance can subscribe.
- Android APK. Native BLE plus a foreground service, so recording survives the screen going off, the phone locking, and the app being backgrounded. Drive sync in the background. Release-signed.
Requirements
- A Bluetooth HR chest strap that advertises the standard Heart Rate Service (0x180D) with RR intervals. Confirmed on the Coospo H808S. Polar H10, Wahoo TICKR, and Garmin HRM-Dual should work on the same spec but have not been individually tested. Apple Watch, Garmin Fenix, and Fitbit do not expose the BLE HR service and are not supported.
- A Chromium browser for the desktop experience. Chrome, Edge, and Brave all work. Safari and Firefox do not implement Web Bluetooth.
- Android 9 or newer for the APK.
Data and privacy
- No accounts needed. Anonymous mode keeps everything on the device.
- Google sign-in is optional. When on, session CSVs sync to your Drive and the viewer reads them across devices.
- Broadcasting to OBS is opt-in. When on, live ticks pass through a Cloudflare Workers relay to subscribers holding the broadcast key. The relay does not persist messages.
- Turn off broadcast and sign out of Google, and nothing leaves the device.
- Not a medical device.
Running it locally
Open index.html in any Chromium browser. No build step, no install. The three HTML files (hr_monitor.html, hrv_viewer.html, overlay.html) are self-contained.
The relay is a small PartyServer (Cloudflare Workers) project under relay/. The mobile Capacitor wrapper under mobile/ builds the APK.
