I mentioned a few months ago that popping off the back of the Xiaomi door/window sensor and connecting the two large solder points resulted in a “closed” state. I finally got around to testing this as a method of integrating hard-wired alarm contacts to ST. Unfortunately I haven’t soldered since high school electronics class (1999) and my $5 soldering iron didn’t work very well, but the concept worked.
Connect the two solder on either side of the printed rectangle on the circuit board with TP6 written inside it.