USB interference and Zigbee
Tonight none of the outdoor automated lights came on. On further testing the internal lights also refused to work. Odd, everything was just fine yesterday.
I use Zigbee devices around the house with four devices controlling various outdoor lighting, two controlling dimmable internal lights and several devices reporting on room and heating temperatures. Two outdoor lights are all-in-one Zigbee bulbs, the others are diminutive units in various electrical boxes. All use 2.4Ghz Zigbee and all the lighting controllers are also Zigbee repeaters and so form a mesh. The whole lot is controlled by a Raspberry Pi with a Zigbee dongle, zigbee2mqtt, mosquitto and homebridge. This also integrates it into the apple stuff so everything can be controlled from the Apple Home app and/or Siri.
Of coure the downside is there are few physical switches now so this was a problem I had to fix. I had no clue what was wrong. Rebooting made no difference. But a bit of searching suggested that USB3 devices can cause issues at 2.4Ghz.
Remember from my previous post that I had attached a SDD to the server? Well, that alone made no difference but was a precursor to the issue. Today I had inadvertently moved the server and the USB3 connected SDD closer to the Pi with the Zigbee dongle! Moving it away cured the issue.
That caught me out - I had no idea USB3 was a potential source of interference. And my master plan may make things worse because I had planned to move all the home automation software and the Zigbee dongle to the server that had caused today's issue, so in a way it's good that it happened as fault finding after the migration would have been real fun. At least now I know to sit the dongle at the end of a really good extension lead to keep it in the clear. Weird stuff, radio.