Hi guys!
I've built aesp8266 thermostat to control my heating system. Everthing seems to be working fine for the moment 
What I want to accomplish is "sniff" or intercept the boiler status from the front panel's status LEDs, to see if this heater is actually turned on, on a MQTT Dashboard.
A very nasty way would be to connect some wires from the boiler's leds to some GPIO pins. But I'm not quite sure about that approach. i believe I would have to use some type of buffer, optoisolator, etc.
(I could also place a LDR, o phototransistor in from of the boiler's LED, but I dont want to physically block the visual feedback)
How could I accomplish this?
Any ideas?
Appreciate your help,
Cheers!
Marc