OHR constantly blink

LwiaNerka said:

When I look beneath the watch I can see that green lights almost always blink very fast. Is that ok?

Yes

When you're within an activity or when you start to be more active in any way(walking a bit or doing some stairs) the green light should be solid.

When no activities are detected the green light blinks.

That's because the sensor measures differently during activities(movement of any kind) and during more quiet periods.