The Vornado fan remote project left me with an RTL-SDR Blog V4 ($25, secondhand off Craigslist) that had only ever looked at one fan’s 433 MHz remote. I used it for a survey of what’s on the air around me in San Francisco. The V4 covers 500 kHz to 1.766 GHz (datasheet), and I began with the rest of the 433 MHz band, where I could hear three weather sensors. This post covers Aug 3 and 4, 2026: an antenna-length calculation that turned out wrong, a sweep of the tuner gain, an eight-hour census of the band, and a weather sensor whose transmit clock drifts with its own temperature reading. ...

I bought a Vornado EOS 9 for the bedroom, a Wirecutter pick. It came with a remote, no protocol listed anywhere, no FCC ID that turned up anything useful. Flipper’s frequency analyzer put it near 433 MHz, and Read mode came back with no protocol match, which meant it wasn’t going to be one of the well-known families. (Read mode isn’t broken: pointed at my actual front-door bell, it decodes CAME 12bit at 315 MHz instantly, no histogram needed. The fan’s protocol is just genuinely unlisted.) So it was Read RAW and reverse engineering from scratch, or nothing. ...

I needed AA and AAA batteries and grabbed an IKEA TIMMERFLOTTE while I was at it. Zigbee temperature and humidity sensor, $8. I put it in my living room: middle of the apartment, between all the windows, so a reasonable representative reading. No real plan. Ten days of data later, I have a clear picture of how this apartment moves heat — and it is not great. Setup The TIMMERFLOTTE logs over Zigbee to Home Assistant. It reports on state change rather than on a fixed interval, so the data is dense: I get a reading whenever temp shifts by about 0.1°F. For outdoor data I’m using Pirate Weather, a privacy-respecting API that pulls from NOAA, exposed as a template sensor in HA: ...

My TV antenna lived behind my TV in the living room. Reception was inconsistent: if someone walked between the antenna and the window, the signal dropped. If I forgot to pull it out and angle it before sitting down, I got nothing. I had an HDHomeRun FLEX DUO from a previous place where I had the antenna setup dialed in. I moved and never got around to setting it up again at the new apartment. The antenna behind the TV was the placeholder that never got fixed. This week I fixed it, and the same day I finished, I used it to watch the FIFA World Cup from an airport lounge and a plane on the way home from a trip, free, with no cable subscription. That felt worth writing up. ...

My resume lives in a git repo. Every time I push, a GitHub Action compiles it to PDF and drops it on a stable URL. No local toolchain needed after the initial setup, no manually uploading PDFs anywhere. Why LaTeX Word docs drift. PDFs exported from Google Docs look fine until they don’t. LaTeX gives me exact control over layout and is just a text file — diffable, versionable, no binary blobs. ...

Two spare Pis sitting around. Already running AdGuard, so Pi-hole was off the table. I wanted something actually useful. I’ve been paying $10/month for Obsidian Sync. The vault lives on my hardware anyway — it felt like paying rent on my own stuff. The alternative: run CouchDB on a Pi, point the Self-hosted LiveSync plugin at it, and use Tailscale to make the Pi reachable from anywhere without port forwarding or a public IP. E2E encrypted, zero ongoing cost, fully under my control. ...

This is how derek.engineer is wired: static Hugo site, PaperMod theme, Netlify deploys, Squarespace DNS, and a local writing workflow that keeps publishing from becoming its own project. The stack Hugo — static site generator, fast builds, zero frontend dependencies PaperMod — clean Hugo theme, installed as a git submodule Netlify — deploys on every push to main, custom domain + SSL handled automatically GitHub — source of truth, all posts are Markdown files in content/posts/ The flow is simple: ...

I recently asked Claude for book recommendations tailored to where I am in my career right now. Build by Tony Fadell came up. I started reading it and was really glad I did. It was written to help founders and executives build companies. The makers inside those companies get just as much from it. What it actually does is give you precise language for things you’ve already experienced but never had words for. Problems you felt but couldn’t name. Org dynamics you survived but couldn’t diagnose. ...

The splitter finally showed up. This session was about seeing if the signal chain actually worked end to end — Apple TV → splitter → TV + B101 — and getting at least one real captured frame out of it. No LEDs wired yet, just proving the capture side works and figuring out the layout. Getting the B101 to see the signal First step after wiring everything up was setting the EDID so the B101 knows what kind of signal to advertise to the Apple TV: ...

derekwelty.com was a Bootstrap 5 single-page site built on the Start Bootstrap Freelancer template. It worked, but it hadn’t been touched in years and updating it required wading through jQuery, a Gulp pipeline, and a bunch of hand-rolled CSS. Time to replace it. The new stack: Hugo with the Congo theme, deployed to GitHub Pages via GitHub Actions. Why Hugo I already run this blog on Hugo + PaperMod via Netlify. The toolchain was familiar, the build times are fast, and Congo gave me a clean profile layout that actually looked like a personal site and not a blog template with the posts removed. ...