Looking for a sensor that can be put over an LED and open/close depending on whether the LED is on or off. Example use cases would be detecting whether dryer is on or off, a cooking surface is hot or not, etc. These would be cases where wiring directly into the LED circuitry isn’t practical. In my case, I want to detect when a Robovac is docked or not (there is a rather bright LED on top that shines when the vac is not docked).
There was mention in a thread about “LED identification sensor” but have found nothing like that. Something like that could be built using a photocell (light-dependent resistor), I guess, but like the idea of something in a package. A lux sensor for dawn to dusk detection would be overkill and a bit larger.