steeman.be

We have all heard the mantra: backups are important, test your backups, follow the 3-2-1 rule. But actually implementing a backup strategy that works reliably, alerts you when something goes wrong, and survives reboots is another matter entirely. This is the story of how I built a comprehensive backup system for my homelab server. Why I finally got serious about backups # The catalyst was a failing hard drive. My backup disk, a Seagate ST2000DM001, started showing signs of degradation. It had been quietly handling daily backups for years, but SMART monitoring revealed it was on its way out. This was the wake-up call I needed to not just replace the disk, but to rethink the entire backup strategy.

After months of preparation, I successfully completed my Tripoli Level 1 high-power rocketry certification on March 1, 2026, at the Tripoli The Netherlands launch site in Exloo. This post documents the build process and flight of my PML Intruder rocket. The Goal # The Tripoli Level 1 certification allows flyers to use H and I-class motors (up to 640 Newton-seconds total impulse). To earn this certification, you must successfully build and fly a high-power rocket with an H motor, demonstrating safe construction and recovery.

There is something philosophically satisfying about running AI on your own hardware. No subscription, no rate limits, no terms-of-service clause about what you can ask. Your prompts stay on your network. The model runs in your house, on your electricity, and answers to no one but you. That was the appeal, anyway. The practical questions were harder: what hardware do you actually need, what does it cost, and does the end result perform well enough to be useful? This post answers all three.

If you look at the timestamps on this website, you will notice a long gap. The last post before this one dates from 2015. That is eleven years of silence — not because I stopped building things, but because managing the website itself became too much of a burden. Why the website went quiet # The site was originally built using Nanoc , a static site compiler written in Ruby. At the time it was a good choice: content in Markdown, a compilation step, clean HTML output. But over the years, a few things went wrong:

My Mespelare firmware doesn’t support Control, TurnOn/TurnOff actions. Since I needed it for my kids bed buttons/lights, I added it to the Mespelare firmware. File versions # From the comments in main.c you can see that I made a new version of the firmware, v1.20. I also modified the MDF and vscp_node_defines and created new versions of these files.

Decision Matrix # 0x0 0x40 0,0x1E,0x05,0,0,37:00:00:00:00:00:00:00:00:00:00:00:00:00:00:99,0x00,0x01,50 Week, bedlight ON (green) at 7u00. Send Control, TurnOn event for zone 1, subzone 50 0000-01-01 00:00:00 9999-12-31 23:59:59 mtwtf-- *-*-* 07:00:00 0 1 50 0x0 0x40 0,0x1E,0x05,0,0,37:00:00:00:00:00:00:00:00:00:00:00:00:00:00:99,0x00,0x01,50 Weekend, bedlight ON (green) at 8u00. Send Control, TurnOn event for zone 1, subzone 50 0000-01-01 00:00:00 9999-12-31 23:59:59 -----ss *-*-* 08:00:00 0 1 50 0x0 0x40 0,0x1E,0x06,0,0,37:00:00:00:00:00:00:00:00:00:00:00:00:00:00:99,0x00,0x01,50 Week+weekend, bedlight OFF (red) at 18:00. Send Control, TurnOff event for zone 1, subzone 50 0000-01-01 00:00:00 9999-12-31 23:59:59 mtwtfss *-*-* 18:00:00 0 1 50

My old Ham-IV rotator has been in storage for a while, but I’m keen on using it again for satellite tracking. Following moving object such as satellites across the sky requires computer control, so I decided to retrofit the Ham-IV’s controller box. After all the rotator controller box is just 3 switches and a position sensing pot, it shouldn’t be too hard to control using a microcontroller. There is an excellent project by Anthony Good K3NG around for adding computer control to rotators. Since it makes no sense re-inventing the wheel, I used his code and built my own custom hardware. It consist of a small 5V power supply, an Arduino Pro Micro clone, a ULN2003A driving 3 relays, 2 pots and an LCD.

My 1981 vintage rotator control box blew its display backlight. Instead of searching for a suitable replacement bulb, I decided to replace it with a LED strip. The replacement is quite simple. The original LED bulb is preserved for historical purposes but slid aside to make room for mounting a piece of LED strip on top of the display. The voltage from the lamp (2 5V AC) is rectified using a small power diode, in my case an 1N4004, sent through a current limiting resistor, and send through the LED strip. A 10microF across the rectified supply is used to smooth the voltage and thus avoid flickering.

This page describes how to automatically send events on the VSCP bus on specific, pre-determined moments. This is useful for example to every night turn off any lights that might have been left on. Add DM row # Add a DM row to the VSCP daemon DM matrix (/srv/vscp/dm.xml): <row enable="true" groupid="wakeup" > <mask priority="0" class="65535" type="65535" GUID=" 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00" > </mask> <filter priority="0" class="65535" type="6" GUID=" 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00" > </filter> <control>0x0</control> <action>0x40</action> <param>0,20,1,0,0,37:00:00:00:00:00:00:00:00:00:00:00:00:00:00:01,1,1,1</param> <comment></comment> <allowed_from>0000-01-01 00:00:00</allowed_from> <allowed_to>9999-12-31 23:59:59</allowed_to> <allowed_weekdays>mtwtfss</allowed_weekdays> <allowed_time>*-*-* *:*:0/20/40</allowed_time> <index bMeasurement="false" > 0</index> <zone>0</zone> <subzone>1</subzone> </row> Detailed explanation # Here’s a detailed explanation of the above DM row:

I plan on using a few spare Nokia Li-Ion batteries for my new quadcopter and was in need of a decent battery charger. This project can charge 5 single cell LiPo or Li-Ion (in my case Nokia BL-5C 1020mAh) batteries simultaneously from a single 6-20VDC power source. It is based on Microchip’s MCP73831 integrated charge management IC, which is powered through a 1117 5V regulator. Here’s the schematic for a single battery.