Optical sensor does not blink :'(

Hi there!
I am currently building my emoncms setup base on arduino ethernet, emonTX shield SMT & optical sensor from the shop (this one)

So I tested by software with an app that make my phone screen blinking.
All works fine and the backside LED of the pulse sensor get ON when my screen is flashing.

So I decided to try real measurement.
For some reason the back side LED of the pulse sensor does not get ON even if I can see the meter pulsing (I switched off the light to see it).
It seems that the sensor catch anyway the blinks,because it send data to emonCMS.

Is it normal behavior? Can it be that the sensor works, but not the backside led ?

I enlarged the hole on the velcro to catch more light

The green LED and the output pulse respond to different light levels - this is known about, I did some measurements some while ago, which you might be able to find if you search.

And it has been reported quite recently: Optical utility meter led pulse sensor own LED does not flash

And my test:
First try with EmonPi - Pulsecount stuck at 1

Thanks for all details!
I’m reporting the pulse count, so I will check if it seems ok over 24h for example, but based on reported watts, it looks all fine.

Emoncms is quite spying tool :grin: