Z-Wave Mystery Action

TL;DR - Apparently it’s possible for a z-wave motion sensor to trigger a z-wave switch directly without Home Assistant! Solution: Change your motion sensor to “Binary Sensor Report.”

Long version:

I installed a new z-wave switch yesterday (Zooz Zen23 toggle in a 3-way configuration) in the morning, then went to work. After I came home that evening, I noticed a couple of times it would turn itself on or off seemingly randomly. I checked the log book and it hadn’t done it all day when no one was home, but whatever, I’ll troubleshoot it tomorrow. Or so I thought until the damn thing started turning itself on while I was sleeping. It’s not in the same room, but I can see the light is on under the door. Super annoying.

Trying to not disturb my sleeping wife – lest she get any (more) reason to discourage my recent “automate all the things” kick – I start digging into HA to see why this might be happening. I only configured one automation tying the switch the front door opening after dark, and that sure wasn’t happening. I turned off all of my automations and it kept happening! So I shut down HA… and it kept happening!

Quick fix: type (from my phone – this sucks) a new HA automation to turn off the light when it turns on. Still annoying because it keeps happening!

Ok… maybe there’s an electrical short and I’m going to burn down the apartment! Do I shut off the breaker? Is the switch bad? Is the other switch firing when it shouldn’t? I’m not going to sleep comfortably without figuring this out.

Finally I happened to associate the light triggering with motion in my bedroom. In retrospect it’s obvious but the motion sensor (Aeotec multisensor 6) has an “on time” of a few mins, so the delay in shutting off is what threw me. Also previously the light was on and turned off by itself, presumably because my wife triggered the motion sensor when the switch was already on, but then it switched off a few mins later when she was in another room.

I dug into the z-wave profile and couldn’t figure out why it was happening. Association? None. It’s past 1:00 AM by this point so I shut off the damn motion sensor and go to sleep.

In the morning I looked at it again and noticed that the “Command Options” (parameter 5) was set to “Basic Set,” but the help text says “OZW Ideal Value is Binary Sensor Report.” Ok, fine, switched to Binary Sensor Report… voila! I have another Aeotec multisensor 6 in the living room, and it’s still configured to Basic Set, but it doesn’t trigger the switch. Tested a couple of things, then switched it to Binary just in case. ¯\_(ツ)_/¯

I’m posting this here in case anyone else encounters this maddening situation in the middle of the night. Also, if anyone could shed some light on why or how this happens, I’d love to understand it better. Meanwhile, I’m hoping it behaves better from now on.