Sometimes the green lights are different

[Scottycool64]

I was just curious why sometimes there are 2 green heart rate lights, (the one in the small round hole which is always on) and the one i. The square hole next to the SpO2 lights. The one in the square hole seems to be on when you put the tracker on, but then later turns off.

[Rich_Laue · Accepted solution]

I'm not sure, but if the lights are not against the skin, then they are at best reacting to changes in light, checking to see if there is anything to detect. 

Basically the lights need to be against the skin to work properly, and if they are against the skin, I can not see them.