A Simple Laser Harp MIDI Instrument

Craig Lindley is a technical author and a prolific maker of things. This simple project was his first attempt to create a laser harp MIDI device. While on vacation, Craig saw a laser harp with only three strings and decided to improve upon it by expanding it to twelve strings. The principle of operation is straightforward: twelve cheap diode laser modules aim a beam towards an LDR, which changes resistance if the light level changes when the beam is interrupted.

The controller is a simple piece of perf board, with a Wemos D1 mini ESP32 module flanked by some passives, a barrel socket for power, and the usual DIN connector for connecting the MIDI instrument. Using the ESP32 is a smart choice, removing all the need for configuration and user indication from the physical domain and pushing it onto a rarely-needed webpage. After a false start, attempting to use a triangular frame arrangement, [Craig] settled upon a simple linear arrangement of beams held within a laser-cut wooden box frame. Since these laser modules are quite small, some aluminium rod was machined to make some simple housings to push them into, making them easier to mount in the frame and keeping them nicely aligned with their corresponding LDR.

Sadly, the magnetic attachment method [Craig] used to keep the LDRs in place and aligned with the laser didn’t work as expected, so it was necessary to reach for the hot glue. We’ve all done that!

An interesting addition was using an M5 stack Unit-Synth module for those times when a proper MIDI synthesiser was unavailable. Making this luggable was smart, as people are always fascinated with laser harps. That simple internal synth makes travelling to shows and events a little easier.

Laser harps are nothing new here; we have covered plenty over the years. Like this nice build, which is more a piece of art than an instrument, one which looks just like a real harp and sounds like one, too, due to the use of the Karplus-Strong algorithm to mimic string vibrations.

Four Steppers Make A Four-Voice MIDI Instrument

Any owner of a budget 3D printer will tell you that they can be pretty noisy devices, due to their combinations of stepper motors and drives chosen for cost rather than quiet. But what if the noise were an asset, could the annoying stepper sound be used as a musical instrument? It’s a question [David Scholten] has answered with the Stepper Synth, a device that takes an Arduino Uno and four stepper motors to create a four-voice MIDI synthesiser.

Hardware-wise it’s as simple as you’d expect, a box with four stepper motors each with a red 3D-printed flag on its shaft to show rotation. Underneath there is the Arduino, plus a robot control shield and a set of stepper driver boards. On the software side it uses MIDI-over-serial, so as a Windows user his instructions for the host are for that operating system only. The Arduino makes use of the Arduino MIDI library, and he shares tips on disabling the unused motors to stop overheating.

You can hear it in action in the video below the break, and we’re surprised to say it doesn’t sound too bad. There’s something almost reminiscent of a church organ in there somewhere, it would be interesting to refine it with an acoustic enclosure of some kind.

This isn’t the first such instrument we’ve brought you, for a particularly impressive example take a look at the Floppotron.

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Forgotten Rock Band Drum Controller As A MIDI Instrument

Happen to have an old Rock Band drum controller collecting dust in your living room? If you also have a spare Arduino and don’t mind parting with that plastic college memento then you’ve got the bulk of what could potentially be your new percussive MIDI instrument. In his project video [Evan Kale] outlines the steps necessary to turn that unloved plastic into a capable instrument for recording.

The whole process as outlined by [Evan] in under seven minutes. This looks like a great weekend endeavor for those of us just starting out with MIDI. After cracking the back of the Guitar Hero drum kit controller open, the main board within is easily replaced with a standard sized Ardunio (which matches the present mounting holes exactly). About 4:50 into the video [Evan] explains how to add a basic perf-board shield over the Arduino which connects the piezo sensors in each of the drum pads to the analog pins of the micro-controller. The MIDI jack that comes built into the back of the kit can also be reused as MIDI out when wired to the Arduino’s serial out pin. By adjusting [Evan’s] example code you can dial in the instrument’s feedback to match the intensity of each hit.

The video with all of the details is after the jump. Or you can check out a MIDI hack that goes the other way and uses a drum kit as a Guitar Hero or Rock Band controller instead

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Guitar Hero As An Instrument Or Midi Controller

[youtube=http://www.youtube.com/watch?v=azfgasnWtW0]

[Robert] wrote a program using Max/MSP that lets him make music with his guitar hero controller. There’s another video after the break where he walks through the various features but here’s the gist of it. This works on Mac and Windows and allows a sort of ‘live play’ or midi mapping mode. In the midi mode each key can be configured to do your bidding. His example uses the pick bar to scroll through different samples and the green button the play them or the red button to stop.

The live mode us much more involved. In the software you choose the type of scale and the key you’d like to play in. This makes up for the controller’s lack of enough frets to make it a chromatic instrument and these settings can be adjust from the controller. There is an up-pick offset that makes the upward movement of the pick bar a different note than the downward movement. The motion control can also be used as an input. He demonstrates pitch bending and cutoff using that method.

This looks like a lot of fun. He needs to team up with [Joran] to add drums to the mix, forming a much more creative rock band than you can buy in the store.

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A Parts Bin MIDI Controller In 24 Hours

Part of the reason MIDI has hung on as a standard in the musical world for so long is that it is incredibly versatile. Sure, standard instruments like pianos and drums can be interfaced with a computer fairly easily using this standard, but essentially anything can be converted to a MIDI instrument with the right wiring and a little bit of coding. [Jeremy] needed to build a MIDI controller in a single day, and with just a few off-the-shelf parts he was able to piece together a musical instrument from his parts bin.

The build is housed in an off-brand protective case from a favorite American discount tool store, but the more unique part of the project is the choice to use arcade buttons as the instrument’s inputs. [Jeremy] tied eight of these buttons to an Arduino Uno to provide a full octave’s worth of notes, and before you jump to the comments to explain that there are 12 notes in an octave, he also added a button to the side of the case to bend any note when pressed simultaneously. An emergency stop button serves as a master on/off switch and a MIDI dongle on the other side serves as the interface point to a computer.

After a slight bit of debugging, the interface is up and running within [Jeremy]’s required 24-hour window. He’s eventually planning to use it to control a custom MIDI-enabled drum kit, but for now it was fun to play around with it in some other ways. He’s also posted the project code on a GitHub page. And, if this looks a bit familiar, this was not [Jeremy]’s first MIDI project. He was also the creator of one of the smallest MIDI interfaces we’ve ever seen.

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The Last Instrument To Get Auto-Tuned

Various decades have their musical signature, like the excessive use of synthesizers and hairspray in the 1980s pop music scene. Likewise, the early 2010s was marked by a fairly extreme use of autotune, a technology that allows sounds, especially vocals, to be shifted to precise pitches regardless of the pitch of the original source. In this dark era, a wide swath of instruments and voices on the charts were auto-tuned at some point, although we don’t remember this iconic instrument ever being featured among the annals of pitch-shifted pop music.

The auto-tuned kazoo created by [Guy Dupont] does its pitch corrections on-the-fly thanks to a built-in ESP-32-S3 microcontroller which, through a microphone inside the kazoo, listens for note of the musician’s hum and corrects it to the closest correctly pitched note. Once it identifies the note it outputs a kazoo-like pitch-corrected note from a small speaker, also hidden inside the instrument. It does this fast enough for live performances using the YIN fundamental frequency estimation algorithm. Not only can the kazoo be played directly, but thanks to the implementation of MIDI it can be used to control other synthesizers or be played through other means as a stand-alone synthesizer.

Much like the 80s, where the use of synthesizers relaxed from excessive use on nearly every instrument on every track throughout the decade to a more restrained use as the decade faded, so has autotune been toned down in most music to be more subtly applied. But like our enjoyment of heavily synthesized tunes outside the 80s like those by Daft Punk or The Weeknd, we can also appreciate something heavily auto-tuned outside of the 2010s like a stylized kazoo or a T-Pain-style guitar effects pedal.

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MIDI Controller In A Cubic Inch

MIDI as a standard has opened up a huge world to any musician willing to use a computer to generate or enhance their playing and recording. Since the 80s, it has it has revolutionized the way music is produced and performed, allowing for seamless integration of digital instruments, automation of complex sequences, and unprecedented control over everything from production to editing. It has also resulted in a number of musical instruments that probably wouldn’t be possible without electronic help, like this MIDI instrument which might be the world’s smallest.

Fitting into a cubic inch of space, the tiny instrument’s volume is mostly taken up by the MIDI connector itself which was perhaps an acceptable size by 1980s standards but seems rather bulky today. A two-layer PCB split into three sections sandwiches the connector in place and boasts an ATtiny85 microcontroller and all the associated electronics needed to implement MIDI. Small threaded screws hold the platform together and provide each layer with a common ground. Four small pushbuttons at the top of the device act as the instrument’s keys.

The project’s creator (and Hackaday alum!) [Jeremy Cook] has it set up to play notes from a piano right now, but has also made the source code available so that any musical action can be programmed onto these buttons. Flexibility is perhaps MIDI’s greatest strength and why the standard has lasted for decades now, as it makes it fairly straightforward to build more comprehensive, easy-to-learn musical instruments or even musical instruments out of retro video game systems.

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