How it works
With every heartbeat, the amount of blood in your face changes slightly, and with it the colour of your skin. You can’t see it with the naked eye, but a camera can measure it. The technique is called remote photoplethysmography (rPPG).
- Find your face: the page detects your face in the webcam image about 30 times per second.
- Pulse signal: an AI model (FacePhys, via the open-source Vital Camera SDK) reads the pulse wave from tiny colour changes in your skin.
- Heart rate: a frequency analysis turns it into beats per minute, updated about once per second. A smoothing filter removes outliers before anything is sent.
- Your overlay: if you turn on sending, only the number goes to HypeRate and shows up in your overlay, just like with a watch.
How accurate is it?
In our first alpha tests (6 sessions, about 100 minutes, measured side by side with a HypeRate watch), the value sent to the overlay was within ±5 BPM of the watch 74 % of the time, 4.7 BPM off on average. Light makes the biggest difference: with a well-lit face, 94 % of readings were within ±5 BPM; in dim light only 34–58 %.
After starting, the measurement needs about 30–60 seconds to settle (43 seconds on average in our tests). After that it follows your heart rate with a delay of a few seconds. The webcam reading is an estimate for entertainment, not a medical measurement.
Tips for accurate readings
- Light from the front: a lamp behind your monitor or a bright screen lights your face evenly. This helps more than anything else.
- Sit still: keep your head relaxed and in the frame. Talking and laughing are fine.
- Fill the frame: your face should take up a good part of the camera image.
- Give it a minute: go live once the progress bar has disappeared.
Privacy
The camera image is processed entirely in your browser; no image is ever uploaded. If you turn on sending, only your heart rate as a number is relayed to HypeRate in real time and not stored. After a session you can voluntarily share the numbers with us (no images) to help improve the measurement, and delete them again at any time.
Frequently asked questions
Do I need a smartwatch or chest strap?
No, any webcam works. If you already use HypeRate with a watch or chest strap, you can compare both values side by side.
How do I show my heart rate on stream?
Copy your overlay link on this page, add it to OBS as a Browser Source and turn on “Send heart rate to HypeRate”. Your heart rate then appears in the overlay.
Is my camera image uploaded?
No. The image is analysed locally in your browser. Only the heart rate number is sent, and only if you turn sending on.
Which browsers are supported?
Chrome and Edge work best: they keep measuring while the tab is in the background. Safari and Firefox work too, but pause the measurement in background tabs.
Can OBS and this page use the webcam at the same time?
On macOS, yes. On Windows, OBS often locks the camera. In that case start the OBS Virtual Camera with output type “Source” set to your webcam and select “OBS Virtual Camera” here.
Is this a medical device?
No. The camera estimate is meant for entertainment and streaming, not for health or medical purposes.
