geekabit

Projects

author Maarten Tromp, published 1 April 2016, last updated 9 December 2022.

One of my main interests is tinkering and making, and I've created a diverse portfolio of projects since I was old enough to wield a screwdriver. These range from electronics to woodworking, from trivial to challenging, from single-afternoon projects to multi-year ones. Results vary from some brilliant pieces to spectacular failures, but I love all of them equally. Check out the projects to discover something that captures your interest.

Reading about other people's projects is something I enjoy, and I find inspiration in their creativity. That's why I've decided to share my own projects here, in the hope that they might inspire the next person or spark their curiosity in some way.

Below you'll find a list of projects, and I'm regularly adding new projects as I finish them or work through the backlog.

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Playable note and octave table

project 5 December 2022, author Maarten Tromp, published 6 December 2022, 278 words.

When I was searching for a table of notes and octaves that I can hear as well, I couldn't find one. So I did what anyone would do and made one myself. It's a useful tool for finding out which octave a note is in, as tuners can sometimes be confused about the octave.

DIY automatic transfer switch

project November 2022, author Maarten Tromp, published 1 December 2022, last updated 15 March 2023, 1778 words.

My friend Herman was looking for an automated transfer switch (ATS) so his PC and modem do not lose power when the circuit breaker trips. An automatic transfer switch will immediately connect your devices to a different power circuit when this happens. Instead of buying a cheap one of dubious quality or spending a lot of money on a professional unit, let's see what we can DIY.

Testing audio codecs

project 30 May 2022, author Maarten Tromp, published 8 June 2022, 709 words.

For years I assumed I could hear the difference between lossy audio compression, such as MP3, and proper uncompressed audio, such as a CD. As musician, sound engineer and general audio enthusiast I should be able to tell them apart easily, right? Today I put this to the test and the results are humbling.

Balanced input on subwoofer

project 15 February 2022, author Maarten Tromp, published 25 February 2022, 563 words.

Always wanted a proper balanced XLR input on a consumer subwoofer? It's not as hard as it might seem, most of it is already in there. Here is the how and why of modifying your subwoofer for balanced input.

Activating passive studio monitors

project 21 January 2022, author Maarten Tromp, published 25 February 2022, 628 words.

How to make passive speakers active? Simply stick an amp on the back. Here is the how and why of mounting power amplifier modules on a pair of passive studio monitors.

Clock sculpture

project June – October 2021, author Maarten Tromp, published 9 December 2022, last updated 29 December 2022, 3090 words.

One day I wondered if it would be possible to make a wall clock out of two concentric rings with leds and all electronics suspended between them. Well, now I know. For this clock there's no need for a circuit board, in fact, it looks even cooler without. Especially with blinkenleds. This article is about my first circuit sculpture.

Led tail light

project January 2021, author Maarten Tromp, published 31 January 2021, last updated 19 January 2022, 4653 words.

There are several advantages of having led lights on your motorcycle, however, mine still used bulbs. So I set about converting the rear light assembly to led.

Teapot warmer

project 8 January 2021, author Maarten Tromp, published 5 November 2021, 417 words.

One day I was looking for a teapot warmer on the internet. My goal was simply to find one and buy it. But after seeing so many beautiful teapot warmers, I ended up wanting to make one myself. This sort of thing seems to happen to me all the time.

Clock chime

project 11 October 2020, author Maarten Tromp, published 6 November 2021, 287 words.

Some years ago I lived very close to a clock tower. What surprised me it that I hardly noticed it toll, but always had a sense of what time it was. Now that I have moved houses, I would like to replicate that feeling. Since we don't have a clock tower nearby, I decided to do the next best thing and write a simple script that plays some striking samples. Like clockwork.

Wake-up-bright

project September 2009 – October 2020, author Maarten Tromp, published 2 April 2016, last updated 15 October 2021, 1921 words.

When I first heard about a wake-up light it sounded like something I would like to try. Gradually waking up with light to me sounds preferable over waking up with a loudly beeping device quite close to my head. But why buy when you can build? My build will be fully tweaked to my preference and only cost a fraction of a commercial unit.

Glove dryer

project February 2020, author Maarten Tromp, published 19 September 2020, 470 words.

Getting your motorcycle kit soaked is as easy as riding into a rainstorm, but how do you get everything dry again afterwards? Especially the inside of the gloves stays clammy for days. Nothing that a hacker can't fix though.

Synchronizing block devices

project February 2020, author Maarten Tromp, published 16 November 2021, 1014 words.

Blocksync does for block devices what rsync does for files. Like rsync it only transfers changes, saving bandwidth, write operations and time, but like dd it works on both files and block devices alike.

Native dark theme for your website

project November 2019, author Maarten Tromp, published 27 October 2022, 612 words.

Implementing a dark theme is quite simple. All you need is some basic HTML and CSS. It will improve site accessibility and keep users like me happy.

Wedding gift for Jeroen and Mingming

project August 2018 – July 2019, author Maarten Tromp, published 13 July 2019, last updated 13 July 2020, 7442 words.

Today, Saturday 13 July 2019, my friend Jeroen (aka Sprite_tm) is getting married to his fiancée Mingming. Of course I had to make them a gift. It should be geek-compatible, flashy and challenging. So why not build them blinking wedding pictograms? Here is the complete story, complete with all the bumps I hit along the road.

Geek jewellery

project 2007 – 2019, author Maarten Tromp, published 6 January 2019, last updated 8 November 2022, 265 words.

For my ~~girlfriend~~ ~~wife~~ ex friend I have made some geeky jewellery gifts over the years.

Some gifts for me

author Maarten Tromp, published 26 August 2018, 714 words.

Here are some of the amazing gifts my friends have made me over the years.

Pan-shaped kitchen lamps

project August 2018, author Maarten Tromp, published 9 December 2022, 350 words.

For years I had this idea to make some fitting lamps for the kitchen. It took a while to find the right tiny pans and matching led spots, but the result is these lovely small pan-shaped lamps, hanging over the kitchen work surface.

Momentary latching switch

project May 2018, author Maarten Tromp, published 6 January 2019, last updated 13 November 2023, 1007 words.

Sometimes you want a button press to be momentary, and sometimes you need it to be latching. This is true for, among other things, guitar effects pedals. And that is why I came up with this small electronics project that lets you do both with only a single button.

Shower hose door loop

project April 2018, author Maarten Tromp, published 6 January 2019, 121 words.

The wire from the smart cat flap kept getting caught by the door. A simple problem, with a simple solution.

Electronics workbench

project March 2018, author Maarten Tromp, published 6 January 2019, 499 words.

In our previous home I had tailor made my electronics bench for our study. It was bolted to the walls and shelves were made all around it. There was no way that desk could easily be moved into the new house. So I started thinking what I would like to have instead. There was no shortage of ideas, ranging from buying a professional lab table to see what I can make from the scrap wood in the shed.

Teapot lampshade

project August 2017, author Maarten Tromp, published 6 January 2019, 359 words.

The teapot at the office had gone leaky. Instead of throwing it out, I offered to adopt it. With some other lamps in mind I thought I might also give the teapot a new life as a lampshade.

Strijklicht

project May 2016, author Maarten Tromp, published 6 January 2019, 296 words.

We happened to have a surplus clothes iron. In the past I had used it for making PCBs, but with the new printer that trick didn't work quite right any more. It seemed like such a waste to throw out a perfectly good iron. But what can you do with it?

Building a keyboard from scratch

project January 2012 – February 2016, author Maarten Tromp, published 1 March 2016, last updated 20 September 2016, 7745 words.

This is the story of me designing and building a computer keyboard from scratch. It covers every step from idea to design to build, from electronics to mechanics to firmware to key layouts and from hits to misses. The result is a unique keyboard and a long story to tell.

Cat-shaped cat door

project January 2016, author Maarten Tromp, published 2 April 2016, 146 words.

Recently our cat developed an annoying new habit. She's usually is asleep in the study upstairs when we go to bed. But in the middle of the night she wakes up and wants to go outside. Unfortunately the closed living room door is in her way, so the can't get out. She found a solution for this problem; start making noise in front of our bedroom door until someone comes out and opens the living room door for her.

RFID shielded wallet

project December 2015, author Maarten Tromp, published 2 April 2016, 490 words.

A low-tech solution to a hi-tech problem.

10 MHz reference clock

project April 2015, author Maarten Tromp, published 2 April 2016, last updated 17 June 2022, 613 words.

When I bought a frequency counter, I expected its clock to match my function generator. It never occurred to me that there could be differences, until I started measuring.

Microscope case

project June 2014, author Maarten Tromp, published 2 April 2016, 375 words.

When I bought a microscope, it didn't come with a case.

Electronic load

project March 2014, author Maarten Tromp, published 2 April 2016, 418 words.

In EEVblog episode 102, Dave explained and built a programmable electronic load. This seemed handy and easy enough to build one myself as well.

Soldering workshop: USB blinkenlights

project June 2013, author Maarten Tromp, published 2 April 2016, 306 words.

With the experience gained from my UTP cable tester soldering workshop, I decided to do it all again once more.

Rail splitter

project 2012, author Maarten Tromp, published 2 April 2016, 318 words.

Sometimes you really need a symmetric power supply, but you only have a single ended one available. Don't you hate that? This is where the rail splitter comes in.

Reverse engineering debugwire

project November 2010 – April 2012, author Maarten Tromp, published 2 April 2016, last updated 24 October 2021, 1731 words.

Debugwire is a proprietary protocol by Atmel for on-chip debugging of AVR microcontrollers. I would like to try it, but debugwire is only supported by Atmel's own programmers. Because of being a proprietary protocol it's not supported by any open source programmer... yet. This would make a nice reverse engineering project. Not encumbered by any experience in this field, I set out to see how far I would get.

Password manager

project November 2011, author Maarten Tromp, published 6 January 2019, 210 words.

When looking for a simple password manager that would work over ssh, I could find none. Everything seemed to be graphical, web based or complex. So I did what any hacker would do, I made one myself.

Drain pipe welding electrode container

project August 2011, author Maarten Tromp, published 2 April 2016, 178 words.

Welding electrodes are hygroscopic, that is why you should keep them dry. Keeping something dry in our shed is a bit of a challenge. The welding electrodes are too long to fit in a normal household container, such as a spaghetti container or any other Tupperware box. Hmm, I wonder if I have anything waterproof in the shed... How about drain pipe?

Bookcase for ring binders

project June 2009, author Maarten Tromp, published 28 January 2020, 529 words.

My dad was looking for a very specific bookcase. It had to be tall enough for 2 rows of ring binders, yet fit under the window sill. The bookcase had to go in the corner, but leave some walking space next to it. Such a bookcase is hard to find in a store. Right about that time I was looking for a woodworking project.

Gear lever coat rack

project September 2008, author Maarten Tromp, published 2 April 2016, 99 words.

Every once in a while you get one of those ideas. Hey, I could use $foo to do $bar, even though it was never designed to do that. Why didn't I think of this before?

Laptop lid mod

project May 2008, author Maarten Tromp, published 6 January 2019, 324 words.

My laptop wasn't all that recognizable. It was a run of the mill Dell and easy to lose between other similar laptops. I would prefer something that stands out a bit more. So let's pick up some tools and start modding.

Circular saw case

project February 2008, author Maarten Tromp, published 6 January 2019, 245 words.

The circular saw I had bought, didn't come with a case. And at the start of 2008 I was in the middle of a burn-out and looking for a simple project and building a case for this saw seemed just right.

Serial USB stick

project March 2007, author Maarten Tromp, published 2 April 2016, 151 words.

For my friend Gert's birthday I made an appropriate present.

Digitally enhanced chandelier

project 2006, author Maarten Tromp, published 2013, last updated 22 November 2022, 2171 words.

This article describes my quest for the perfect dimmer for my chandelier. Over the years I worked on several modifications to gain remote controlled brightness per lightbulb, and then successively undid all the changes to arrive at a dimmable chandelier once more.

Trunk lid lock protection bar

project June 2006 by Kees Stein and Maarten Tromp, author Maarten Tromp, published 6 January 2019, 452 words.

What do you do when the trunk lid of your car stops closing properly? You investigate and (over)engineer a solution.

Fake car radio front

project May 2006, author Maarten Tromp, published 2013, 254 words.

This article describes how I transformed my old car radio into a detachable front for my new car radio.

Soldering workshop: UTP cable tester

project April 2006, author Maarten Tromp, published 2 April 2016, 521 words.

Some of my friends were interested in electronics, but had never soldered before. Since I love to talk about electronics and teach people new things, the idea for a soldering workshop was born. I had recently designed and built a simple UTP cable tester and this would make an ideal workshop piece. It took me half an hour to build it on breadboard, so how hard could it be?

Crate bed

project December 2005, author Maarten Tromp, published 2 April 2016, last updated 19 September 2019, 456 words.

By the end of 2005 I was looking for a new bed. The old mattress was worn pretty thin, I didn't like the frame and the bed wasn't even mine to begin with. I had already got hold of a decent but odd sized (1900 x 1200 mm) mattress. Where do you find a frame this size? I can build a bed frame myself, of course, but didn't want to spend too much time and money on the bed.

Virtual tour of my student house

project June 2003, author Maarten Tromp, published 18 July 2020, 349 words.

I always enjoy giving people a tour around the house and my student home was no exception. Unfortunately everyone seemed to find Enschede a long way off, so I created a virtual tour. It's inspired by point-and-click adventure games like Gobliiins and Leisure Suit Larry 3 that I was playing at the time. It would also be a nice opportunity to put my brand new digital camera to use.

Musical alarm clock script

project October 2002, author Maarten Tromp, published 16 October 2021, 521 words.

My noisy computer had been my alarm clock for almost a year. But now that my computer was silent enough to just leave on during the night, how about waking up with some nice music instead?

Universal Cereal Bus

project May 2002, author Maarten Tromp, published 6 January 2019, 40 words.

Where do you store your breakfast cereal?

Alarm clock switches computer on

project February 2002, author Maarten Tromp, published 6 January 2019, 514 words.

My student room was a single room. I had a huge self-assembled computer with killer specs, but it was so noisy I couldn't sleep with it powered on. So in the evening I would power down the computer, go to sleep, and in the morning, get out of bed and power it up again. Now how can we automate this?