i’ve tried it with a step-down-converter and a 5-V-relay. This won’t work, because the Hörmann could only provide 25 mA @ 24 V. This seems to be to less power. I’ve tried it with the relay, because i don’t know the stability of the 24 V.
If i connect the step-down converter directly to the GPIO-Pin, i didn’t know how to do this.
As i wrote above, the solution with a relay didn’t work.
Therefore i took the risk of destroying the Sonoff-SV an added a voltage divider.
Now i have a voltage level of 3.1 V on the GPIO-Pin when the garage is open. This solution is now working for three day now… Seems to be that the 24 V signal is clean…