steeman.be
DIY, Electronics, Rocketry, Homebrewing & More
The personal website of David Steeman. Electronics, rockets, ham radio, home energy and the occasional brew.
Recent
From Code to Copper: What AI Can Do for Hardware Makers
·2964 words·14 mins
AI that writes code is old news. This is what it does for me once that code has to drive real electronics: firmware, testing over USB, parts and schematics, measurements and old hardware, and where it still needs a human with a multimeter.
Choosing an Igniter Charge for the I400
·826 words·4 mins
Four open-air tests to pick an igniter charge for the I400: 2 g and 3 g of zinc-sulphur, and 2 g and 3 g of CuO-Al thermite. The thermite won, and it goes into the next static test.
The I400: Designing and Testing an I-Class Rocket Motor
·2671 words·13 mins
My own reloadable 42 mm I-class rocket motor on home-made RNX-71V epoxy propellant: the design numbers, the hardware, how the grains are cast, and what the first static test showed.
PML Intruder Level 2 Certification Flight
·3181 words·15 mins
Flying the same PML Intruder on a J motor for my Tripoli Level 2 certification in September 2026, now with dual deployment and a camera section, and comparing the flight with the simulation.
Measuring a Rocket Motor with an NI USB-6009
·2200 words·11 mins
A Python data logger for static motor tests on an old NI USB-6009: thrust, chamber pressure, break wires and igniter current, in the order a test day runs. Successor to my 2008 and 2010 test electronics.
Verba: An Offline Latin Vocabulary Trainer on a USB Stick
Verba, a Latin vocabulary trainer for my son’s 1051 words, in a single HTML file that runs from a USB stick without a network. How the word list was built and how the learning engine works.
Inside the ESP32 Rocket Launch Controller: Firmware, Protocol, and Architecture
·5249 words·25 mins
How the wireless launch controller works inside: the functional design, firmware architecture, the full list of safety measures, the encrypted radio protocol, sensing and how it was tested.
A Wireless Rocket Launch Controller on ESP32s
·3884 words·19 mins
A two-unit wireless rocket launch controller for VRO, built on ESP32-S3s with an encrypted radio link, and the case for why done properly it is safer than a long firing cable.
Fri3d Friends: A Friend Finder and Contact Swap for the Fri3d Badge
·2370 words·12 mins
A Fri3d Camp 2026 badge app that tells you when your friends are nearby over Bluetooth, swaps contact details with a button press and is set up from a phone. It also has a camp-wide game of Gotcha.
I Vibecoded My First Fri3d Camp 2026 Badge App: And You Can Too
·1441 words·7 mins
How I went from an idea to a published Fri3d Camp 2026 badge app in an afternoon with AI-assisted coding, step by step, so you can do the same.
Running the Fri3d Camp 2024 Badge on ESPHome and Home Assistant
·1340 words·7 mins
A complete ESPHome configuration for the Fri3d Camp 2024 badge, so it shows up in Home Assistant with its motion sensor, LEDs, display and battery. Covers the driver choices that were needed.
Programming the Fri3d Camp 2024 Badge with Claude Code
·1963 words·10 mins
A hands-on guide to writing your own apps for the Fri3d Camp 2024 badge with Claude Code: backing it up, the firmware model, MicroPython and a real app with the fri3d framework.
Building a Woordklok: A Dutch Word Clock
·956 words·5 mins
Building a Dutch word clock from the DJO Amersfoort design, with a few changes of my own to the case, and tracking down why it showed the wrong time after it was finished.
Reverse-Engineering the Platinum 3100S solar inverter's RS485 Protocol
·1796 words·9 mins
An attempt to read a Platinum 3100S solar inverter directly over its proprietary RS485 protocol with an ESP32. It has not cracked yet, so the full dataset is published for anyone who wants a go.
Predicting Where a Radiosonde Will Land: and Testing It Against a Real Flight
·2301 words·11 mins
Predicting where a weather balloon’s radiosonde will land from its own radio telemetry alone, testing it on a real flight, and backtesting it against years of launches from Uccle.
Offsite Backups on a Raspberry Pi, with a Key That Lives Only at Home
·1890 words·9 mins
An encrypted offsite backup on a Raspberry Pi at a relative’s house, reached over Tailscale, whose LUKS key never leaves home. Covers the threat model, the boot unlock and a dead-man’s switch.
Controlling a RunCam Thumb Camera with an ESP32-C3
·1516 words·8 mins
An ESP32-C3 that controls a RunCam Thumb over its serial protocol: start recording the moment power arrives, and check and control the camera from a web page on its own Wi-Fi access point.
Peak-Shaving the Belgian Kwartierpiek with Marstek Batteries and Home Assistant
·1848 words·9 mins
Keeping the Belgian capacity tariff down with three Marstek Venus E batteries and Home Assistant: how the kwartierpiek is billed, the settings that matter and two traps I nearly fell into.
Bringing a Second-Hand Solar-Log 500 Online
·2348 words·12 mins
Getting a second-hand Solar-Log 500 to read my Platinum 3100S solar inverter over RS485 and feed its production into Home Assistant. The wiring polarity and the firmware were the real obstacles.
Turning a Cheap Yellow Display into a Home Assistant Control Panel
·3144 words·15 mins
Turning an ESP32 Cheap Yellow Display into a desk panel with ESPHome that shows the house’s power use and opens the door or garage with a tap. Four gotchas along the way.
Tracking My AI Usage Limits in Home Assistant
·2096 words·10 mins
Home Assistant sensors for the five-hour and weekly usage limits of my Claude and z.ai coding plans, including reverse-engineering the z.ai API and a dashboard.
Syncing Claude Code Across Multiple Machines
·1093 words·6 mins
Keeping Claude Code’s settings, skills and project context in sync between a desktop and a laptop with a Synology NAS, symlinks and Syncthing, plus split changelogs.
Building a TiltBox: A Tiny Tilt-Controlled Game Console
·1491 words·7 mins
Building a TiltBox, a small wooden game console with an 8x8 LED matrix that you play by tilting it. ESP32-C3, an ADXL345 accelerometer, a home-made front panel and a few contributions back to the project.
Beyond ChatGPT: Building Your Own AI Toolkit
·3986 words·19 mins
Why I moved from pasting into ChatGPT to an AI toolkit that does the work: Claude Code in the terminal, cheaper GLM models from z.ai, plan and API pricing compared, and a switcher between backends.
One Desk, Three Machines, One Keyboard: My Multi-Monitor Productivity Setup
Seven screens across three computers on one desk, controlled with a single keyboard and mouse through InputLeap. The layout, a custom monitor stand and the cable management.
Local Audio Transcription with Speaker Diarization
·3748 words·18 mins
A Docker container on an RTX 3090 that transcribes audio locally with Whisper, labels who said what, fixes names with an LLM pass and can write a summary. No audio leaves the machine.
Labeling My Basement Inventory: From Herma Stickers to a Dymo LabelWriter
·1811 words·9 mins
How labelling my parts storage grew from round Herma stickers to a Dymo LabelWriter driven by a LibreOffice spreadsheet and macro, including a long fight with label orientation.
My custom Claude Code setup
·3452 words·17 mins
The Claude Code setup I settled on after months of daily use: a dedicated machine, config synced across computers, a model selector for three backends, session recording and a custom status bar.
Building a Robust Linux Backup Strategy with Borg
·4033 words·19 mins
The backup system for my homelab server, triggered by a failing disk: Borg with encrypted repositories, a local disk, a NAS mirror and an offsite Raspberry Pi, with retention and alerts.
PML Intruder Level 1 Certification Flight
·2299 words·11 mins
Building and flying a PML Intruder for my Tripoli Level 1 certification at Exloo in March 2026: the build, the simulation, the recovery and what the flight log really shows.
Running 32B AI Models at Home: How I Built My Local LLM Workstation
·2711 words·13 mins
The hardware and software behind running 32B language models at home: why VRAM decides everything, the full build, Ollama, tuning from 5 to 35 tokens per second, and how well it actually works.
Managing my website with Claude Code
·1210 words·6 mins
How Claude Code brought this site back after eleven quiet years: moving from Nanoc to Hugo and Blowfish, migrating every post, keeping old URLs working, and deploying.
Kids bed button and wake-up lights
·87 words·1 min
Bed buttons and wake-up lights for the kids, driven by VSCP: the lights turn green at a set time on weekdays and later at the weekend. The decision matrix rows that make it work.
Adding TurnOn - TurnOff action
·171 words·1 min
Firmware v1.20 for the Mespelare node adds the Control TurnOn and TurnOff actions, needed for the kids’ bed buttons and lights. Shows where the new code hooks into the decision matrix.
Converting a Ham IV rotator to computer control
·1618 words·8 mins
Adding computer control to a Ham IV antenna rotator for satellite tracking, using K3NG’s rotator code on an Arduino Pro Micro with an LCD, and calibrating the heading.
Replacing a HAM IV rotator display bulb by LEDs
·171 words·1 min
Replacing the blown backlight bulb of a 1981 Ham IV rotator controller with a strip of LEDs, a diode, a resistor and a capacitor.
Scheduling VSCP events
·273 words·2 mins
Sending VSCP events at set times from the daemon’s decision matrix, for example to turn off every light that was left on at night. Each field of the DM row explained.
5-way LiPo battery charger
·391 words·2 mins
A charger that tops up five single-cell LiPo or Li-ion batteries at once from one 6 to 20 V supply, built around Microchip’s MCP73831 charge controller. Schematic and board included.
REX C100 teardown
·972 words·5 mins
What is inside the 10 euro REX C100 PID temperature controller from eBay, in photos.
Controlling VSCP from a web page
·643 words·4 mins
Switching lights on the VSCP bus from a web page, with buttons and status indicators that talk to the VSCP daemon over websockets. Includes the decision matrix and daemon configuration.
Setting up OpenHAB development environment on Ubuntu
Setting up an openHAB development environment on Ubuntu 14.04: the Git clone, Java, the Yoxos installer, Maven and a test build.
Quick tour of my home automation system
·12 words·1 min
A short video tour of my VSCP-based home automation system.
Check-list for configuring Mespelare nodes
·186 words·1 min
My checklist for configuring each Mespelare node as it goes into the house: loading the register template, mapping inputs to outputs and setting the LED and output control registers.
Fixing a Yamaha 9.5A pull-cord
Replacing the broken pull cord on a Yamaha 9.5A outboard, including how to handle the recoil spring safely. Documented in reverse order of disassembly.
Slow PWM on Arduino
·821 words·4 mins
A slow PWM controller on an Arduino with a potentiometer and a solid-state relay, to set the heating power of a Weck kettle when boiling wort.
Frankengrinder
·315 words·2 mins
Making a missing slotted bushing for a Hobbymat MD65 lathe without a mill, by mounting a grinder on the lathe to cut the slot.
Aquarium dosing pump
An automatic fertiliser doser for the aquarium, made from a 230 V mechanical timer whose slow geared motor turned out to be just right for driving a syringe.
Raspberry Pi door bell
·968 words·5 mins
A doorbell built on a Raspberry Pi with a camera that e-mails a photo of whoever rings. Power supply, button wiring, the Python script and mounting.
Estimative index
·273 words·2 mins
Feeding the plants in my indigenous aquarium with the Estimative Index: dosing macro and micro nutrients on a schedule instead of measuring them with test kits.
Installing VSCP on a Raspberry Pi
·2849 words·14 mins
Installing vscp_software on a Raspberry Pi, every command with its output, from package updates and dependencies to building the software.
Raspberry Pi setup
·617 words·3 mins
My notes for setting up a Raspberry Pi B+ as a VSCP daemon server and doorbell: static IP, hostname, NAS share, Samba and VNC.
Change CAN speed
·213 words·1 min
Switching the Hasselt VSCP firmware from its non-standard 250 kbps CAN bus speed back to the 125 kbps everyone else uses. A small register change in vscp18f_init().
Actuating a local output from a local input trigger
·857 words·5 mins
Making a Mespelare VSCP node switch its own relays from its own buttons, so the lights keep working when the bus is down. Covers the code hook, a configurable output mapping and output modes.
Update sendCANFrame()
·262 words·2 mins
Fixing a hang in sendCANFrame() when VSCP Works reads many registers at once, with a one-second send timeout.
Changing interrupt timer period
·570 words·3 mins
Changing the Hasselt firmware’s Timer0 tick from 10 ms to 1 ms for the Mespelare node, and updating the code that relied on the old period. Includes a scope capture of the result.
New action Pulse
·848 words·4 mins
A new Pulse action for the Hasselt firmware, so the decision matrix can drive the pulse relays in my house. Firmware, MDF and decision matrix changes.
Solder reflow oven
·1261 words·6 mins
Turning a domestic oven into a PCB reflow oven with the Hobbybotics reflow controller firmware: PID temperature control, solder profiles, a display and a PC application.
VSCP register addressing
·1236 words·6 mins
How VSCP register addressing works: how registers in the MDF map onto the node’s application space and how the firmware stores them.
Building a custom MDF
·245 words·2 mins
A walk through the structure of a VSCP Module Description File, from the XML header and module information to the registers, using the Mespelare module’s own MDF as the example.
Cleaning a Siemens clothes dryer
·107 words·1 min
A Siemens condenser dryer kept reporting a full water tray when it was empty. A very thorough clean fixed it, at a fraction of the repair quote. Photos of every step.
Upgrading Mespelare firmware to XC8
·754 words·4 mins
Migrating the Mespelare firmware from Microchip’s retired C18 compiler to XC8, following the migration guide section by section.
Unbricking the PICkit3
·710 words·4 mins
Bringing a bricked PICkit3 back to life by reprogramming its firmware with a PICkit2.
Camera holder
·200 words·1 min
A quick plywood cabinet that gives my Nikon D3000 a fixed place on the workbench, with a USB cable routed in so it can stay connected.
Mespelare proof-of-concept
·378 words·2 mins
A final prototype, Mespelare v9, to make sure the board design is right before ordering production PCBs. The fixes from v6, the tests and the firmware.
VSCP roadmap
·554 words·3 mins
My roadmap for a VSCP home automation system, from the toolchain and testing Kurt’s boards to the Mespelare node, production and a reflow oven.
Updating VSCP firmware
·921 words·5 mins
Updating the Mespelare node to the latest vscp_firmware from GitHub, and the compile errors and changes that came with it.
APRS tracker
·150 words·1 min
A small PIC 16F648A APRS tracker running the OpenTracker firmware, with a 300 mW HX1 transmitter on the back and a header for a GPS module. Hand-solderable 1206 parts.
Dumping EEPROM contents
·775 words·4 mins
A DumpEEPROM() routine that prints the node’s EEPROM over the serial port, to check what VSCP Works actually wrote. Needed because every published Hasselt MDF turned out to be wrong.
Electronics components cabinet
·311 words·2 mins
A cheap plywood cabinet that stores SMD and through-hole parts in small screw-cap yoghurt-drink bottles, each with a label on the cap.
Adding serial debugging
·631 words·3 mins
Adding a serial debug port to the Hasselt VSCP firmware, so you can watch variables and program flow while the PIC runs. One #define switches all the debug output on or off.
The Mespelare Decision Matrix
·342 words·2 mins
Configuring the Mespelare node’s decision matrix through its registers so it reacts to events on the VSCP bus.
Dissecting the Hasselt firmware
·1186 words·6 mins
A function-by-function walk through the Hasselt VSCP firmware that the Mespelare node is based on, from the interrupts and main() to event handling, with a program flow diagram.
Indigenous aquarium
·729 words·4 mins
Bringing my childhood aquarium back as a low-cost, low-maintenance tank with local plants and fish, in the basement workshop for the kids to enjoy.
Installing USB2CAN on Linux
·875 words·5 mins
Getting the USB2CAN interface running with VSCP on Ubuntu: the driver, the VSCP daemon and testing the bus with VSCP Works.
Printing Excel lists onto labels
·613 words·3 mins
Printing a different text on every label from an Excel list with Herma Label Designer’s database import, for labelling component jars.
Installing VSCP Daemon on Windows
·899 words·5 mins
Installing, configuring and testing the VSCP daemon on Windows, so several applications can share one bus interface. Includes the catches I ran into.
Table saw slide
·308 words·2 mins
A sliding table for my table saw that always runs square to the blade, replacing a fence that never stayed parallel.
Bottle cap labels
·273 words·2 mins
Labelling homebrew on the bottle cap instead of the bottle, with round Herma 4386 stickers printed from Herma’s free Label Designer. Readable in the crate and nothing to scrub off afterwards.
Pillar drill table
·478 words·3 mins
A bigger table with a sliding precision fence for a cheap pillar drill, made from scrap multiplex and rubberwood, for drilling repeatable holes.
Hacking the PlayStation 1
·963 words·5 mins
Modding a PlayStation 1 with a programmed PIC mod chip so it plays copied discs: how the mod works, opening the console, programming and installing the chip, and testing.
Snelkoppeling voor flessenspoeler
·260 words·2 mins
A small change that lets the Blast bottle rinser click onto a standard hose quick-connector instead of being screwed onto the tap. In Dutch.
Hacking the Rigol DS1052E
·1831 words·9 mins
Step by step: turning a 50 MHz Rigol DS1052E oscilloscope into its 100 MHz DS1102E twin with a firmware hack, then upgrading the firmware and calibrating the scope.
Getting started with VSCP
·114 words·1 min
A reading list for VSCP beginners: the protocol introduction and specification, VSCP Works, filters and masks, the decision matrix and setting up the daemon on Linux.
Running the Mespelare firmware
·1433 words·7 mins
Adapting the Hasselt code to the Mespelare board: pin assignments, the MDF location and setting the registers, then running it on the hardware for the first time.
Mespelare VSCP firmware
·773 words·4 mins
Compiling kurtsidekick’s Hasselt firmware for the first time in MPLAB X, as the starting point for the Mespelare firmware: target settings, preserving EEPROM and programming the test board.
My beer recipes
·402 words·2 mins
All the beer recipes I have brewed so far, as spreadsheets, with the ones worth brewing again in bold.
VSCP toolchain
·1958 words·10 mins
The hardware and software I use to learn and develop for VSCP: MPLAB X, a PICkit 3, a USB2CAN converter and VSCP Works.
Mespelare VSCP node
·797 words·4 mins
The Mespelare VSCP node: a CAN bus board that reads a Niko six-button panel, drives its LEDs and six relay outputs, and breaks out the rest of the pins for expansion boards.
How does my website work?
·298 words·2 mins
How the old version of this site was made: articles written in Markdown, compiled into a static site with Nanoc, with categories, image thumbnails and self-hosting.
About my website and me
·311 words·2 mins
Who writes this site and why: a personal, unpolished collection of technical projects for people who stumble on them with the same interests. Also covers the technical side and the licence.
TS-50 USB interface
·673 words·4 mins
A USB CAT interface for the Kenwood TS-50 made from a cheap USB-to-TTL adapter, and how to connect it to the radio.
Beer rack
·263 words·2 mins
A rack under the basement stairs that holds 23 cases of beer, built from cheap pine and sized for Duvel crates. The cases sit half on their side so every bottle can be reached without lifting a crate.
Pillar drill bottle capper
·260 words·2 mins
Turning a pillar drill into a sturdy bottle capper, with a lathe-turned capping head and a bottle support that sets the height.
Automated brewery
·77 words·1 min
A small automated brewery for 28 litre batches, built around a Weck kettle and a BrewTroller controller as a cheaper alternative to a Braumeister. A photo series of the build.
Homemade malt mill
·712 words·4 mins
A two-roller malt mill built as a metalworking exercise, with an adjustable gap so the grain is crushed fine while the husks stay mostly whole for lautering.
Building the MiniMost
Building the MiniMost, a small plywood boat from a 1960s Popular Mechanics design, to put a second-hand 2 hp outboard to use. Build log in Dutch.
Homemade magnetic stir plate
·878 words·5 mins
A stir plate for growing yeast, built around an 80 mm computer fan with PWM speed control, plus thermostat-controlled heating, in a two-level case.
Fishing raft
A floating platform with a sofa bed, a tent and a barbecue that we built, took onto the river and lived on for a few days of fishing. Mostly photos.
Ballistic Evaluation Motor test 3
·1680 words·8 mins
The third firing of the Ballistic Evaluation Motor, run to check the fixes from test 2, with the load cell now on a steel plate. Report in Dutch with data, sound and video.
Ballistic Evaluation Motor test 2
·2676 words·13 mins
The second firing of the VRO Ballistic Evaluation Motor, with a wider throat and a new igniter tube after the first test failed to light. Observations, audio, video, measured data and the fixes for next time.
Static Test Controller
·1676 words·8 mins
An integrated measuring system for static motor tests on the Ballistic Evaluation Motor: load cell, pressure sensor and break wires read into a computer. In Dutch.
Load cell amplifier
·3451 words·17 mins
A load cell amplifier for static rocket motor tests, with the ADC on board, that plugs into USB and records the thrust curve for analysis in a spreadsheet.
16F88 Rocket timer
·2465 words·12 mins
A compact four-channel rocket timer built around a PIC 16F88. It detects lift-off with an accelerometer or a reed switch and fires up to four pyro charges at programmed intervals, independently or in groups.
TS-50 serial interface
·1288 words·7 mins
A home-built serial CAT interface for the Kenwood TS-50 so logging software can follow band and mode changes. Superseded by the USB version.
My QSL card
·246 words·2 mins
The story behind the photo on my QSL card: the Hydrocopter that carried me across the ice to Holmön island (EU-135) for a DXpedition in Sweden.