How to monitor % open of a balcony sliding door

[John_Land]

Here's one solution for one type of sliding door lock-state detector for a particular type of sliding door:

Prototype contact sensor for sliding patio door LOCK

OK, here's my final design for a sliding door patio lock open/close sensor. I took an Aqara Zigbee magnetic contact sensor, carefully opened it up, and hooked 30AWG wires to the ends of the reed switch (both of the following photos are pre-soldering and trimming of the wires). The Aqara sensor is only about 11mm high and JUST fits in the sliding door channel without blocking (or being crushed by) the door when closed. In a previous version, I cut the glass shell of the reed switch, but I left …