Work below the software layer.

My products have always sat on physics I took on faith — radio links, sensor noise, orbits. In May 2026 I started working through that substrate deliberately: primary sources, hardware on the bench, one layer at a time. I already operate the middle of this stack in the field — 424 thermal-drone missions at a hundred meters over Bavarian meadows — so this page works outward from there: down to millimeters, up to orbit, and into the layer where sensing becomes a decision.

None of it is product. That’s the point — this is a lab notebook, updated as the threads move. The structured courses below are generated and run with tutor, a Claude Code plugin I built for exactly this kind of learning.

Millimeters — 3D Printing & CAD

How does an idea become a part that fits?

A QIDI Q2 arrived in early May, and SolidWorks alongside it — modeling from zero, one part at a time. So far the printer’s main customer is the bench itself: a printer riser, an air-blower adapter, a desiccant storage box for the filament dryer — and an enclosure for an ESP32 dev board.

The early lesson: printing is mostly materials discipline. Filament is hygroscopic and prints badly wet, so drying became its own small experiment — a dryer, airtight desiccant boxes, trial runs across PLA, PETG, and ASA at different temperatures and humidities. Screw threads want heat-set brass inserts, not cut plastic. A soldering station covers the electronics side of the same builds.

Next: more SolidWorks, and the thread’s real target — a printed, battery-powered enclosure for the UWB dog-collar tag, where Millimeters meets Centimeters.

Centimeters — UWB Ranging

How far away is my dog on our walks — in centimeters, live?

The dog is Loki — a Labrador, currently working his way through Bavaria’s hunting-dog exams. The question cost €149 in dev boards and opened the deepest thread on this page. Two Ai-Thinker BU04 boards (Qorvo DW3000 radios) have been doing live two-way ranging on my desk since May — distance readout over serial, accurate to about two centimeters.

The boards range out of the box; understanding them is the actual project. I wrote myself a nine-phase curriculum — embedded C, RF propagation, chip-level radio work — with stop-and-verify gates on every lesson, and I’m working it on a bare-metal STM32: boot model, linker script, memory-mapped registers, OpenOCD debugging. No HAL, no Arduino, no generated firmware.

• Phase 0 — Setup, tooling, foundations
• Phase 1 — Embedded & C fundamentals
• Phase 2 — RF & signal foundations
• Phase 3 — DW3000 chip basics
• Phase 4 — First range: SS-TWR
• Phase 5 — Better range: DS-TWR + antenna-delay calibration
• Phase 6 — Field-test & harden
• Phase 7 — Display
• Phase 8 — Direction: PDoA / AoA (stretch)
• Phase 9 — Doppler primer (diversion)

The hardware delivered its first lesson early: I assumed the BU04 carried an ESP32, the documentation said STM32F103 — and the whole curriculum repivoted from ESP-IDF to bare-metal STM32 within a day. An ESP32-S3 sits on the shelf for the wireless-telemetry phase.

Next: register-level DW3000 over SPI on Qorvo’s reference boards, the ranging variants (SS-TWR vs DS-TWR), and eventually a battery-powered tag small enough for his collar.

Local Spectrum — SDR Receiving

What is actually in the air around me?

A HackRF One with a PortaPack runs standalone — no laptop needed. Received and decoded so far: aircraft transponders (ADS-B), ship traffic (AIS), weather satellites, ham voice, broadcast — plus a lot of waterfall time learning to tell a real signal from an artifact. I keep analyst-style cheat sheets as I go: bands and modulation, a discovery workflow (“there’s a blip — now how do I hear it?”), decode modes, antenna choices.

The rules matter here. Receiving is broadly legal in Germany; transmitting without a licence is not — so the radio stays in receive and I’m working through the Class A amateur-licence syllabus, as much for the RF theory as for the licence itself. The active side of the spectrum stays theoretical for the same reason: I built myself a 17-chapter electronic-warfare curriculum, from spectrum fundamentals up.

Next: PC-side signal processing (a DragonOS dual-boot is already set up), more decode modes — and perhaps a Faraday enclosure for transmit experiments that never leave the box.

Orbit — SAR & Thermal

My drone covers a hundred hectares in a morning. What does the same problem look like from 500 kilometers up?

Thermal imaging is already my operating domain — fawn rescue lives and dies by heat contrast in the half hour around dawn. This thread works the same physics at orbital scale. The hands-on start: I flew a photo grid with my drone, built an orthophoto in WebODM, and overlaid it on Sentinel-2 imagery in QGIS — a practice run for the workflow, and a visceral lesson in what 10-meter pixels do and don’t show.

Alongside the hands-on work: NASA ARSET trainings (fundamentals of remote sensing; thermal remote sensing for urban heat islands), a nine-chapter SAR course, and the physics underneath — why thermal bands sit where they do, what the atmosphere lets through, what land-surface temperature actually measures.

Next: deeper into SAR, then hands-on time with public SAR and thermal scenes.

Analysis — Intelligence Tradecraft

How does sensor data become a decision someone will stake something on?

Every rescue-season morning I run a small version of this loop myself: fields reported, drones tasked, finds triaged, crews dispatched. The literature reads less like theory than like scaled-up versions of problems I’ve already had. The current reading program: Cynthia Grabo’s Anticipating Surprise on warning intelligence, Mark Lowenthal’s Intelligence: From Secrets to Policy, Robert Clark’s target-centric Intelligence Analysis, and Biltgen & Ryan’s Activity-Based Intelligence. Alongside the books I keep the domain itself as a linked graph — missions, functions, platforms, payloads, sensors — 140 notes and growing, so every new concept has to earn a place in an explicit structure.

The thread I keep pulling is sensor fusion — how observations from different sensors, none sufficient alone, become one picture somebody can act on.

Next: keep reading, with a bias toward how warning actually fails.