A Childhood Dream, Created And Open Sourced

October 7, 2025 by Tyler August 12 Comments

Some kids dream about getting a pony, others dream about a small form factor violin-style MIDI controller. [Brady Y. Lin] was one of the latter, and now, with the skills he’s learning at Northwestern, he can make that dream a reality — and share it with all of us as an open source hardware project.

The dream instrument’s name is Stradex1, and it’s a lovely bit of kit. The “fretless” neck is a SoftPot linear potentiometer being sampled by an ADS1115 ADC — that’s a 16-bit unit, so while one might pedantically argue that there are discreet frets, there’s 2^15 of them, which is functionally the same as none at all. Certainly it’s enough resolution for continuous-sounding pitch control, as well as vibrato, as you can see at 3:20 in the demo video below. The four buttons that correspond to the four strings of a violin aren’t just push-buttons, but also contain force sensors (again, sampled by the 16-bit ADC) to allow for fine volume control of each tone.

A few other potentiometers flesh out the build, allowing control over different MIDI parameters, such as what key [Brady] is playing on. The body is a combination of 3D printed plastic and laser-cut acrylic, but [Brady] suggests you could also print the front and back panels if you don’t happen to have a laser cutter handy.

This project sounds great, and it satisfies the maker’s inner child, so what’s not to love. We’ve had lots of MIDI controllers on Hackaday over the years — everything from stringless guitars to wheel-less Hurdy-Gurdies to say nothing of laser harps galore — but somehow, we’ve never had a MIDI violin. The violin hacks we have featured tend to be either 3D printed or comically small.

If you like this project but don’t feel like fabbing and populating the PCB, [Brady] is going to be giving one away to his 1000th YouTube subscriber. As of this writing, he’s only got 800, so that could be you!

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Turning A Typewriter Into A Mechanical Keyboard

August 27, 2015 by Brian Benchoff 18 Comments

Is your keyboard too quiet? Is your Cherry MX Blue board not driving your coworkers crazy enough? If the machine gun fire of a buckling spring keyboard isn’t enough for you, there’s only one solution: [Russell]’s typewriter turned into a mechanical keyboard.

Converting typewriters into keyboards has been done for a very long time; teletypes, the first computer keyboards, were basically typewriters, and the 1970s saw a number of IBM Selectrics converted into a keyboard with serial output. Even in recent years, typewriters have been converted into keyboards with the help of some switches and an ATMega. [Russell]’s mechanical keyboard improves on all of these builds by making the electronic interface dead simple, and a project that can be done by anyone.

Instead of installing switches underneath every key or futzing about with the weird mechanics of a Selectric typewriter, [Russell] is only installing a touch-sensitive position sensor into the frame of the typewriter. When a key is pressed, it strikes a crossbar in the frame of the typewriter. With a single ADC chip and a Raspberry Pi, [Russell] can determine which key was pressed and use that information to output a character to a terminal.

It’s a very simple solution for an electrical interface to a mechanical device, and the project seems to work well enough. [Russell] is using his new keyboard with Vim, even, something you can check out in the video below.

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Arduino Synth Guitar Really Rocks

February 25, 2015 by Rick Osgood 18 Comments

[Gr4yhound] has been rocking out on his recently completed synth guitar. The guitar was built mostly from scratch using an Arduino, some harvested drum pads, and some ribbon potentiometers. The video below shows that not only does it sound good, but [Gr4yhound] obviously knows how to play it.

The physical portion of the build consists of two main components. The body of the guitar is made from a chunk of pine that was routed out by [Gr4yhound’s] own home-made CNC. Three circles were routed out to make room for the harvested Yamaha drum pads, some wiring, and a joystick shield. The other main component is the guitar neck. This was actually a Squire Affinity Strat neck with the frets removed.

For the electronics, [Gr4yhound] has released a series of schematics on Imgur. Three SoftPot membrane potentiometers were added to the neck to simulate strings. This setup allows [Gr4yhound] to adjust the finger position after the note has already been started. This results in a sliding sound that you can’t easily emulate on a keyboard. The three drum pads act as touch sensors for each of the three strings. [Gr4yhound] is able to play each string simultaneously, forming harmonies.

The joystick shield allows [Gr4yhound] to add additional effects to the overall sound. In one of his demo videos you can see him using the joystick to add an effect. An Arduino Micro acts as the primary controller and transmits the musical notes as MIDI commands. [Gr4yhound] is using a commercial MIDI to USB converter in order to play the music on a computer. The converter also allows him to power the Arduino via USB, eliminating the need for batteries.

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Stribe 1 Kits Available

November 13, 2008 by Eliot 11 Comments

stribe

We first spotted the Stribe music controller at Maker Faire. [Josh Boughey] has since refined the controller’s design so that it can be constructed in a modular fashion and it’s being sold in kit form by Curious Inventor. The kit has two columns of 64 LEDs and a Spectra Symbol SoftPot for control. You can daisy chain eight modules together using a ribbon cable. It uses SPI control, with a separate wire for the data line (not in the ribbon). An Arduino is used to hook the controller to programs like Max/MSP.