Fitbit has a relax option that shows a circle animation to sync your breath to. There are similar devices like Dodow which project this on the ceiling.
It shouldn’t be too hard to show a breath sync light by alternating the brightness of the screen while showing a orange light. Why Dodow chose a blue light still baffles me.
This is something I’ve been eyeing myself, the Dodow precisely (and yes, also don’t understand their blue light choice ;)). Implementation-wise, it would be quite simple, what do you think about that @petr-urbandroid?
That would be really nice! Maybe including an integration with the Smartlight (Like Philips Hue)
The Dowdo is a little bit too expensive for just 3 LEDs + an Microcontroller…