category: Tech & dev

I have a SensorPush outdoor temperature/pressure/humidity sensor that I’m pretty happy with. It’s BLE, it’s reliable, its range is good, it seems pretty accurate. However it doesn’t report its battery level in its adverts, but the manufacturer app can read this level through reading GATT characteristics. I previously had a go at adding this to my HA two years ago. It worked for a while, but the distance between my desktop at the front of the house, and the sensor in the back garden became too far when I tried to protect the sensor from the sun with more aluminium foil. Using a desktop for this always felt a little over-engineered, so moving back to the UK has given me an excuse to try it again with ESPhome. ...

I have a grage door. It has an opener. I am slightly too lazy to wire up the external controls of my garage door opener. But it does have an app, and the app shows the state of the door opening and closing. Using the esp32_ble_tracker and some debugging ESP_LOGDs, we can see: [19:25:28][D][ble_adv:060]: Advertised manufacturer data: [19:25:36][D][ble_adv:062]: - 02026d200000: (length 6) [19:25:36][D][ble_adv:062]: - 13c000000000000000e489feb375b43104: (length 17) This is actually a single long advert sequence (that I forgot to keep an example of) that is type-length decoded to these two separate manufacturing messages. The manufacturing ID is set to 0x07B4 for both. ...

My wife asked for a sensor that would inform her of the next bus here in Ottawa. Turns out they have an actual API! Someone had tried this on the forums before but said the API had changed1. ...

I’m pretty happy with my SensorPush outdoor temperature/humidity/pressure sensor. It’s not cheap but it is calibrated to work in a Canadian winter (most of it, at least). Their BLE adverts are automatically detected by HomeAssistant and decoded. Sometimes it appears to have a bit of a nap, adverts stop arriving (and I’ve checked with other BLE receivers) until the Android app wakes it up, probably the direct Bluetooth connection is all it wants. Also, the battery voltage doesn’t appear to be broadcast. SensorPush do actually publish an API but they only show the GATT characteristics that require active scanning. Also my readings don’t agree with their statement that I can read battery temperature. The Android app happily returns 20.9C (which seems high!), raw values seem to float around 0xffff. So, rather than try to get an ESP32 to lock up its active connection, draining the battery to see how quickly the battery is draining, I’m going for something more intermittent. ...

A nerd friend bought me a LILYGO E-paper display1, in the exact hope that I’d end up going down the rabbit hole of Smart Things. I have gone down this bloody rabbit hole. I’ve always been a sucker for data, and I aspire to heating my home more efficiently by measuring temperatures round the house and seeing how they change as I change demand. This is not a place of honour. It’s a place of a lot of YAML and black magic. It’s pretty cool when it works though: The board is a micro with Wi-Fi and a big-enough E-Paper Display (EPD) I can reconfigure it via context-aware text editor in the browser Push updates (also from the browser) Do some reasonably complex data processing and image/text rastering on the micro itself Control it from either a self-hosted server on the micro or from Home Assistant ...

Do I like Foundry as a Virtual Table Top? Yes, love it. Do I recommend it to others? Uh, well, it depends on your definition of “recommend” 😬 Some idle screaming-into-the-void on Mastodon prompted a conversation with the Old Scouser Roleplayer about my Foundry setup, and I realised I end up typically saying the same thing a lot about Foundry: It is a beautiful product, especically for crunchier games You will absolutely get distracted with doors, and sight lines and music, and audio effects, and away from the actual game It is an utter pain to use securely. The word “securely” here is key. There have been some cracking vulnerabilities in the software already (fixed already!). The developers are moving fast and breaking things, and that’s great for making a beautiful VTT with some really novel features, but less good for boring, stuffy, security. So I love Foundry, but I don’t trust it. Let me explain. ...

I have a spare laptop. I’m not going to spend ages cutting it up to make an actual photo-frame, and neither will I build one from scratch with a Raspberry Pi Zero. I’m just going to put it by the TV and see whether my wife and I look at it. Requirements: Show pictures after power on Get pictures from the NAS Auto-update them ...

How many pictures? I like taking pictures. How many pictures? Well, you know, some. $ find ~/pix/cam -type f | wc -l 10167 $ du -sh ~/pix/cam 47G ~/pix/cam That does not include pictures taken on my various mobile phones. And how many have I printed? Well, I think I have less than twenty framed. And I made two photobooks, and I’m not sure when I looked in them last. 😬 I try to finesse them down, weed out the crap (there’s a lot of bad pictures), crop, enhance, etc. And that’s hard and is a never-ending job and I’m just looking at them on my computer then, and my wife doesn’t see them at all. So, let’s show ’em off. This is a solved problem right? Right? ...

Never written up the few technical projects I’ve done on here, so here’s an old project, a clock to show the next sea tides. I got it on hackaday, which I’m very pleased with. A tide clock, complete There’s a set of journal posts on the project page for it and source code. ...