Im a not an electronic engineer nor do I understand optical science so forgive my basic pleas for help.
I want to detect a light on my heating boiler. I think the led is on a PCB and there is a tube that directs the light to a diffuser on the front panel. The light is Green but not sure if that is diffuser or the led?
I used a very basic phototransistor circuit emitter to ground, collector to 3.3v via a resistor. I am feeding the collector to a raspberry pi gpio input. It works fine when testing against a bright Green led (3.3v via 330Ohm resistor). However, when I try and detect the boiler light it doesn’t work.
I have tried increasing the resistor on the collector from 10K to 500k then 1M and next 6M. This definitely helped with the sensitivity on my test breadboard with a dimly lit LED. Unfortunately, it still didn’t detect the boiler light? Should it be able to detect light through a “diffuser”? Would an LDR be a better option, this isn’t high frequency stuff, only to detect when a boiler is running? I only have a cheap Multimeter and tried measuring volt drop across resistor but gave up:)