You Don't Live Like I Do

Last night, after a very pleasurable theatre trip with cosmolinguist, I ended up messing around a bit with the smart plugs I bought ages ago.

I have actually been using these plugs somewhat. They're on the house WiFi and that lets me remote-control them through a browser and set timers for them. They also have a mechanical button if you want to interact with them in a more traditional manner - that's basically a hard requirement for any home automation stuff I do, after the time I visited a friend and had to poop in the darkness because the bathroom lights couldn't be switched on until he reinstalled a Raspberry Pi.

But having resurrected Home Assistant on my fileserver I figured it was time to actually get these things talking to each other. I still find HA overly complicated, and I'm not quite sure what the difference is between an "app" and an "integration". I hit a few dead ends following this guide but eventually got to the point where I could use the Home Assistant web UI to control the plugs rather than the built-in web UI.

That doesn't sound like much of an improvement but it's actually quite exciting, because now anything I can do with Home Assistant, I can do with the plugs. I installed up simple speech-to-text and text-to-speech integrations in HA, and now I can talk to the HA app on my phone, tell it to turn the plugs on or off, and it does so! And tells me it's done it in a northern voice called Alan!

It's another small step on the HA journey and I'm still not thinking about temperature monitoring around the house, but it gave me a nice little dopamine hit.

(by this time it was 2am and E prodded me to come to bed, so I excitedly demonstrated this to him and then went to sleep)

Just replaced the BIOS battery in mother_bones' laptop. A CR2016 cell costs about 50p and we happened to have a spare one in the battery box; the laptop SKU replacement part is just one of those, with two electrodes attached to a small connector. It's shrink-wrapped so you can't easily replace the battery within. A replacement part costs about £8-20.

So I carefully disassembled the part, cutting open the shrink rap with a craft knife, removing the electrodes from the cell with a spudger, and removing the last of the shrink wrap. I replaced the cell, and reconstructed the part as best I could, sellotaping it back together.

It's a bodge, but it works - no more clock complaints on boot-up. Saved us a few quid, and I got it fixed tonight rather than having to wait for a part to arrive.

I've finally got round to installing Home Assistant on my file server. This is the first time I've played with virtual machines since transplanting the hard drives from an Intel box to an AMD box, and I needed to purge and reinstall bits of KVM / QEMU to get it to work.

Of course now it's up and running it doesn't do very much on its own. There are various things it can theoretically do which I'm interested in, including tracking Gary around the house using a tag on his harness. But my starting point is pretty simple - measuring temperature and humidity in every room in the house.

The design principle is pretty solid - I plug a USB Zigbee stick into my fileserver, and it should be able to reach devices across the house. I buy some Zigbee sensor units from AliExpress for about a fiver a pop, pair them with the contoller, and deploy them around the house. Home Assistant handles monitoring, logging, graphing and alerting. Maybe I need a Zigbee router/repeater unit on the landing because my house is basically a Faraday cage, but that should be the only complication.

In practice, I've pretty much immediately hit a brick wall with this. Either I choose between ready-to-use units (which tend to use WiFi and are much more expensive per-unit), or I go for something slightly more homebrew and run into a host of problems. I've seen advice that you shouldn't use Bluetooth (as Linux support isn't good enough) or Zigbee (as Linux support is too good for the devices out there), the two cheap low-power alternatives. Or I go the ESPHome approach and solder things together myself, which is pretty much a non-starter at my skill level.

I suspect I'll end up just buying some random units from AliExpress and seeing what works, but it's frustrating that I either have to do this kind of expensive, slow trial-and-error or pay through the nose for what should be cheap kit.

This morning, cosmolinguist couldn't find the CO2 monitor which we use to maintain Covid safety during the ongoing pandemic. It was last in my possession on Friday.

I realised that it was within Bluetooth range of my phone, since the Aranet app could talk to it, which limited the search range. Then I set it to buzz every time it registered a critical level, and set the critical level threshold to 310ppm (normally outdoors is around 400). This caused the monitor to buzz every time it took a reading (60 seconds), which helped us track it down!

It was my fault for leaving it in my hoodie pocket rather than returning it to the fireplace where it normally resides, but I'm glad I could do something nerdy to help find it when I was still half asleep!