Fun with Dome range extender (DMEX1) and other HA lessons learned

A few months ago I installed a Dome Range Extender in our laundry room to help extend the mesh to nearby sensors. I used the default settings and generic “Zwave Range Extender” handler and didn’t think much of it. This device has a night light on it that will turn on when the built in light sensor detects low light levels which seemed like a bonus.

For the most part my zwave mesh has been really solid and doesn’t give me any issues. Maybe an occasional issue but otherwise works well.

A few weeks ago I happened to have live logging running and noticed that every few seconds the Dome Extender was logging a SwitchBinaryReport. This went on for 10-15 minutes or so and then stopped. I chalked it up to weirdness and moved on. Since then I’ve caught it doing it several times and figured out that it always seemed to be around the same time in the afternoon, but not every afternoon. After some thought it dawned on me…

Every time the night light turns on or off, the device sends a SwitchBinaryReport to indicate its new status.

And this photo should tell you what was going on…

When the sun was setting in the afternoon, the light level in the room decreased to the “on” level of the nightlight. Nightlight turns on, sends a SwitchBinaryReport. When the light in the room was high enough AND the lid of the washing machine was open, the nightlight would reflect back into the sensor and it would turn back off. Once the nightlight was off, the level in the room was low enough that it would turn back on again, sending another message…
This would go on until the sun was low enough that the light reflecting back + room light wasn’t above the threshold.

I added logging/counting to the messages and it ends up sending 800 or so SwitchBinaryReport messages in about 10 minutes.

Lesson learned: Disable the night light feature. Its not needed anyway. And sometimes the simple explanation is the non obvious one!

Footnote: As Kevin mentions here, the device does support 2 parameters that are mentioned in the manual that are supposed to set the on and off levels of the nightlight. By default, they both reported “5”, so I thought maybe if I set those to other values (and not the same threshold) the device wouldn’t have the same behavior of rapid nightlight changes causing a message flood. Kevin was right, the device’s behaviour does not change based on those settings. Dome DMEX1 Range Extender/Repeater device handler? - #9 by krlaframboise