I saw a video showcasing this idea some time back. They showed slowed-down video that exaggerated both the colour red, and the lines on your face, neck and hands, following a steep logarithmic slope.

Basically it showed that we imperceptibly blink and undulate like freaky globular aliens, and even consumer level cameras can pick it up. Not so different than a deep ocean jellyfish. Really fascinating stuff, so I'm looking forward to the Android version of your app.

Let me know if you want a beta tester for Android. I can test if it matches the heart rate monitor on the stationary bike, and there's all kinds of weird lighting at the gym I go to. Plus I do HIIT, so my heart is purposely increased/decreased to significantly different target rates every few minutes.

That's totally right! It's incredible just how much ambient information is visible to consumer cameras that human eyes and brains can't or don't process.

We're always happy for more beta testers, especially with a variety of diverse situations and environments (true heart rate, lighting conditions, etc).

To sign up as a beta tester, fill out the Android Sign Up form at https://heartrate.hedronvision.com/ - that will let us reach out with a beta app when we build it!

Done deal. I'll put in a little sweat for you when it's available.

Co-creator here! Feel free to ask us anything.

Check it out if you can — it downloads really quickly, and it's free!

Looks really awesome! Does it work in a variety of lighting conditions?

We've tested across quite a few--and it should control for constant, weird lighting.

But there are definitely edge cases that are hard to control for--a faint, pulsing red light would probably be the worst one.