Author: Bryan Cockfield

1714 Articles

3D Printing A Piano Action

November 13, 2025 by 14 Comments

Part of the reason there are always free pianos on your digital classifieds listing of choice is that, at least economically speaking, a piano is less of a musical instrument and more of a complicated machine that can and will wear out (not to mention the physical difficulty of actually moving one). Once a piano reaches that point, whether through age, use, or neglect, at that point it’s to intents and purposes worthless. But still, they’re essentially just machines. [Toast] figured that, since 3D printers not only can print all kinds of other machines and musical instruments alike, he would take a stab at combining these two and made his own 3D printed piano.

A piano’s action is the mechanical linkage between the keys and the strings of the piano themselves. Over many hundreds of years this has developed into a complicated series of levers which not only rapidly strike strings when a key is pressed, but also mute the strings while the key is not being pressed and strike the strings in a way that the hammer won’t be pressed into the strings if the player leaves their finger on a key. Rather than try to recreate all of this in meticulous detail, [Toast] has swapped out the strings for a series of tubes which, unlike strings, do not much change their musical behavior if the hammer remains on the tube after being struck. This greatly simplifies the action (and cost) of his miniature piano.

The piano works by positioning hammers above these tubes, which strike downwards when a musician depresses the keys. Rubber bands return the hammers to their upright positions after the key is lifted. The instrument went through a few stages of design as well where [Toast] refined the size and shape of the tubes as well as improved the way by which the hammers are attached to the keys.

Is it still a piano if it has pipes instead of strings? Perhaps, but at the very least we can all agree that he’s built a working keyboard action capable of producing music, if not an outright definitionally-accurate piano. It’s an interesting build that we hope to see more iterations of in the future, if not to build a more functionally accurate 3D printed piano action then to see what is possible from a 3D printer in the piano space. Despite their complexity and weight, pianos are a fundamental and popular instrument in the Western music tradition and we’ve seen many interesting builds around them like this modern player piano built with a series of solenoids. Continue reading “3D Printing A Piano Action” →

2025 Component Abuse Challenge: Relay Used As Guitar Pickup

November 13, 2025 by 16 Comments

We’ve all built projects that are a rats’ nest of wiring and feature creep, but the best projects in the end are usually those that use a simple solution to elegantly solve a problem. [Kauz] had been thinking about a unique type of electric guitar pickup for a while and rather than purchase an expensive option or build a complex microcontroller-based system he found his elegant solution in the form of a common electronic component.

The core of this idea is that guitar pickups are essentially coils of wire, and are surprisingly similar to the coils of wire found in electromechanical relays. [Kauz] has used six small relays, left them unmodified, and then built an amplifier circuit for each to allow the vibrations of the guitar strings to resonate in the relay coils, eventually producing a sound. Not only do the relays work perfectly well as pickups, but [Kauz] also created a mixing board that allows the six relays to be combined into two channels, allowing for options like stereo sound for different strings directly out of the guitar or for different effects to be applied to different strings.

The build also allows for some interesting options in future versions as well. [Kauz]’s plans are eventually to build this into an instrument which can output polyphonic MIDI signals, where various strings can behave as different instruments. In theory, with six circuits six different instruments can be produced, and we’re excited to see what the next versions will look and sound like. In the meantime, be sure to check out some other guitar pickups we’ve seen that use even simpler parts found lying around the workbench.

Continue reading “2025 Component Abuse Challenge: Relay Used As Guitar Pickup” →

Pi Compute Modules Make For Compact Cluster

November 12, 2025 by 23 Comments

Raspberry Pi clusters have been a favorite project of homelabbers and distributed computing enthusiasts since the platform first launched over a decade ago, and for good reason. For an extremely low price this hardware makes it possible to experiment with parallel computing — something that otherwise isn’t easily accessible without lots of time, money, and hardware. This is even more true with the compute modules, as their size and cost makes some staggering builds possible like this cluster sporting 112 GB of RAM.

The project is based on the NanoCluster, a board that can hold seven compute modules in a form factor which, as [Christian] describes it, is about the size of a coffee mug. That means not only does it have a fairly staggering amount of RAM but also 28 processor cores to work with. Putting the hardware together is the easy part, though; [Christian] wanted to find the absolute easiest way of managing a system like this and decided on gitops, which is a method of maintaining a server where the desired system state is stored in Git, and automation continuously ensures the running environment on the hardware matches what’s in the repository.

For this cluster, it means that the nodes themselves can be swapped in and out, with new nodes automatically receiving instructions and then configuring themselves automatically. Updates and changes made on Git are pushed to the nodes automatically as well and there’s not much that needs to be done manually at all. In much the same way that immutable Linux distributions move all of the hassle of administering a system to something like a config file, tools like gitops do the same for servers and clusters like this, and it’s worth checking out [Christian]’s project to get an idea of just how straightforward it can be now.

DIY Pinball Machine Uses Every Skill

November 1, 2025 by 6 Comments

Pinball machines have something for everyone. They’re engaging, fast-paced games available in a variety of sizes and difficulties, and legend has it that they can be played even while deaf and blind. Wizardry aside, pinball machines have a lot to offer those of us around here as well, as they’re a complex mix of analog and digital components, games, computers, and artistry. [Daniele Tartaglia] is showing off every one of his skills to build a tabletop pinball machine completely from the ground up.

Continue reading “DIY Pinball Machine Uses Every Skill” →

Recreating A Homebrew Game System From 1987

October 29, 2025 by 10 Comments

We often take for granted how easy it is to get information in today’s modern, Internet-connected world. Especially around electronics projects, datasheets are generally a few clicks away, as are instructions for building almost anything. Not so in the late 80s where ordering physical catalogs of chips and their datasheets was generally required.

Mastering this landscape took a different skillset and far more determination than today, which is what makes the fact that a Japanese electronics hobbyist built a complete homebrew video game system from scratch in 1987 all the more impressive.[Alex] recently discovered this project and produced a replica of it with a few modern touches.

Continue reading “Recreating A Homebrew Game System From 1987” →

Original E39 Head Unit Modernized

October 28, 2025 by 24 Comments

Although most modern cars have moved to using proprietary components nearly everywhere, especially when it comes to infotainment systems, for a brief moment which peaked in the 90s and 00s most cars shipped with radios that fit in a standard size opening called a DIN slot. If you wanted a new Pioneer or Kenwood stereo it was usually a simple matter to slide the factory radio out and put your choice of aftermarket head unit in its place. [Stefan] has an E39 BMW from this era and wanted to upgrade the factory radio but use the original hardware instead of replacing it.

This isn’t just a simple stereo upgrade either. [Stefan] has gone all-out for this build which he started in 2020. Beginning with a Kotlin/Jetpack Compose Linux application to handle control input from the vehicle’s various knobs and buttons he moved on to a map application and an on-screen keyboard. From there he implemented VGA to send video to the OEM screen, and now has a fully functional system based on a Raspberry Pi. It does everything the original unit can do including playing music and showing the feed from the backup camera, plus adds plenty of new, modern features like Bluetooth.

For a certain classic car enthusiast, this build hits a sweet spot of modernizing a true classic like the E39 without removing or permanently modifying any OEM components. The amount of work that went into it is pretty staggering as well, with [Stephan] putting in over 100 hours of work just to get the video signal timing correct. We also like it because it reminds us of the flash-in-the-pan “carputer” trend from the late 00s where people in the pre-smartphone age were shoving all kinds of computing horsepower in their trunks.

Mushrooms As Computer Memory

October 28, 2025 by 35 Comments

Fungi make up a massive, interconnected part of Earth’s ecosystems, yet they’re vastly underrepresented in research and public consciousness compared to plants and animals. That may change in the future though, as a group of researchers at The Ohio State University have found a way to use fungi as organic memristors — hinting at a possible future where fungal networks help power our computing devices.

A memristor is a passive electronic component whose resistance changes based on the voltage and current that has passed through it, which means it can effectively remember past electrical states even when power is removed. To create these circuit components with fungus, the researchers grew shiitake and button mushroom mycelium for these tests, dehydrated their samples for a number of days, and then attached electrodes to the samples. After misting them briefly to restore conductivity, the samples were exposed to various electrical wave forms at a range of voltages to determine how effective they were at performing the duties of a memristor. At one volt these systems were the most consistent, and they were even programmed to act like RAM where they achieved a frequency of almost 6 kHz and an accuracy of 90%.

In their paper, the research group notes a number of advantages to building fungal-based components like these, namely that they are much more environmentally friendly and don’t require the rare earth metals that typical circuit components do. They’re also easier to grow than other types of neural organoids, require less power, weigh less, and shiitake specifically is notable for its radiation resistance as well. Some work needs to be done to decrease the size required, and with time perhaps we’ll see more fungi-based electrical components like these.