Sense led on or off

    I have a garage door open closed indicator device.

    Very simple when the door is open, a tilt sensor transmitter sends a signal and the red led turns off and the green led turns on.

    The LEDs in the receiver are about 2.2 volts.

    Is there a way to read the LED on off status?

    A photo transistor or opto isolator type device.

    The receiver itself is 12 volts DC so I can power the uni. I need a way to read the LEDs and trigger an event or post to mqtt.

    The simplest and not very dangerous way (for the electronics!) would be to replace one or both indicator LED by photo couplers. The LED part of the coupler has to be installed in place of the LED indicator. Be aware of the polarity! The transistor part of the coupler is mounted between SENS GND and IN-1/-2 of the Shelly UNI (emitter of NPN transistor to SENS GND; collector to IN-x). Due to fact this is an open collector arrangement, a pull-up resistor of approx. 4,7kΩ to 20kΩ must be tied from IN-x to +12V DC supply of Shelly UNI.

    A more sophisticated solution would be to get a deeper insight in the driver circuit for the LED indicators of the tilt sensor and to couple the UNI directly to the driver outputs. Skills in electronics are essential! Especially the ground potential of both circuit must be matched!

    „Habt Geduld. Alle Dinge sind schwierig, bevor sie einfach werden!“ (aus Frankreich)

    „Nothing in life is to be feared, it is only to be understood.“ (Marie Curie, 1867-1934)

    „Es reicht nicht“, rief Schiller, „Gedankenfreiheit zu fordern, man muß auch denken können, sonst fordert man Gedankenlosigkeitsfreiheit und die ist die Freiheit zur Dummheit, welche wiederum die schlimmste Unfreiheit überhaupt ist!“
    (Aus „Besuch aus Weimar“ von Gert Heidenreich, Schriftsteller, *1944 in Eberswalde)