Viessmann "Optolink" reading head
A little reading head for reading data out off the Viessmann Optolink interface.
You need
1x M4x5mm screw
1x M4 press-in thread
1x IR transmitting Diode
1x IR Phototransistor
1x 10kΩ restistor
1x 220Ω restistor
1x some wire with 4 strands
I have my code for ESP8266 from:
https://github.com/empty88/OptoLink