MIDI And A Real Vox Humana Come To A Century-Old Melodeon

A hundred years or more of consumer-level recorded music have moved us to a position in which most of us unconsciously consider music to be a recorded rather than live experience. Over a century ago this was not the case, and instead of a hi-fi or other device, many households would have had some form of musical instrument for their own entertainment. The more expensive ones could become significant status symbols, and there was a thriving industry producing pianos and other instruments for well-to-do parlours everywhere.

One of these parlour instruments came the way of [Alec Smecher], a pump organ, also known as a harmonium, or a melodeon. He’s carefully added a MIDI capability to it, and thus replaced its broken “Vox Humana” tremolo effect intended as a 19th century simulation of a choir, with a set of genuine human sounds. There is an almost Monty Python quality to his demonstration of this real Vox Humana, as you can see in the video below.

Lest you think though that he’s gutted the organ in the process of conversion, be rest assured that this is a sensitively applied piece of work. A microswitch has been placed beneath each key, leaving the original mechanism intact and working. An Arduino Leonardo has the microswitches multiplexed into a matrix similar to a keyboard, and emulates a USB MIDI device. It’s fair to say that it therefore lacks the force sensitivity you might need to emulate a piano, but it does result in rather an attractive MIDI instrument that also doubles as a real organ.

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MIDISWAY Promises to Step Up Your Live Show

If you like to read with gentle music playing, do yourself a favor and start the video while you’re reading about [Hugo Swift]’s MIDISWAY. The song is Promises, also by [SWIFT], which has piano phrases modulated during the actual playing, not in post-production.

The MIDISWAY is a stage-worthy looking box to sit atop your keys and pulse a happy little LED. The pulsing corresponds to the amount of pitch bending being sent to your instrument over a MIDI DIN connector. This modulation is generated by an Arduino and meant to recreate the effect of analog recording devices like an off-center vinyl or a tape that wasn’t tracking perfectly.

While recording fidelity keeps inching closer to perfect recreation, it takes an engineer like [Hugo Swift] to decide that a step backward is worth a few days of hacking. Now that you know what the MIDISWAY is supposed to do, listen closely at 2:24 in the video when the piano starts. The effect is subtle but hard to miss when you know what to listen for.

MIDI projects abound at Hackaday like this MIDI → USB converter for getting MIDI out of your keyboard once you’ve modulated it with a MIDISWAY. Maybe you are more interested in a MIDI fighter for controlling your DAW. MIDI is a robust and time-tested protocol which started in the early 1980s and will be around for many more years.

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Cheap DIY MIDI to USB Adapter

[Joonas] became frustrated with cheap but crappy MIDI to USB converters, and the better commercial ones were beyond his budget. He used a Teensy LC to build one for himself and it did the job quite well. But he needed several converters, and using the Teensy LC was going to cost him a lot more than he was willing to spend. With some tinkering, he was able to build one using an Adafruit Pro Trinket which has onboard hardware UART (but no USB). This lack of USB support was a deal killer for him, so after hunting some more he settled on a clone of the Sparkfun Pro Micro. Based on the ATmega32U4, these clones were just right for his application, and the cheapest to boot. He reckons it cost him about $5 to build each of his cheap USB MIDI adapters which receive notes and pedal data from the keyboard’s MIDI OUT and transmit them to a computer

Besides the Pro Micro clone, the only other parts he used are a generic opto-coupler, a couple of resistors and a MIDI connector. After testing his simple circuit on a bread board, he managed to squeeze it all inside an old USB dongle housing, stuffing it in dead-bug style.

The heavy lifting is all done in the firmware, for which [Joonas] used LUFA — the Lightweight USB Framework for AVR’s. He wrote his own code to handle MIDI (UART) to USB MIDI messages conversion. The interesting part is his use of a 32.15 kbps baud rate even though the MIDI specification requires 31.25 kbps. He found that a slightly higher baud rate fixes a problem in the AVR USART implementation which tends to miss consecutive bytes due to the START edge not being detected. Besides this, his code is limited in functionality to only handle a few messages, mainly for playing a piano, and does not have full-fledged MIDI capabilities.

We’ve featured several of [Joonas]’s hacks here over the years, the most recent being the Beaglebone Pin-Toggling Torture Test and from earlier, How to Turn A PC On With a Knock And An ATTiny.

Push Buttons, Create Music With A MIDI Fighter

Musicians have an array of electronic tools at their disposal to help make music these days. Some of these are instruments in and of themselves, and [Wai Lun] — inspired by the likes of Choke and Shawn Wasabi — built himself a midi fighter

Midi fighters are programmable instruments where each button can be either a note, sound byte, effect, or anything else which can be triggered by a button. [Lun]’s is controlled by an ATmega32u4 running Arduino libraries — flashed to be recognized as a Leonardo — and is compatible with a number of music production programs. He opted for anodized aluminum PCBs to eliminate flex when plugging away and give the device a more refined look. Check it out in action after the break!

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Fidget Spinner Gets Useful as MIDI Controller

Fidget spinners are not only a fad, but pretty much useless. Sounds like a job for hacking to make the toys have some actual purpose. [D777k] took up the challenge and created a MIDI controller from a common spinner. You can see a video of the results, below.

The device uses a LightBlue Bean controller and Garage Band as the MIDI software. Granted, it might not be super useful, but it is better than just a plain old spinner. [D777k] calls it a “whirling dervish of sound making!

The Arduino code that drives the thing is very simple. It reads three axes of acceleration and uses that to drive the MIDI software. When the acceleration exceeds a threshold, the software creates a new note based on the sums and differences of the accelerations.

The Lightblue Bean isn’t anything new, but it is well suited for this kind of service. Certainly, making a toy into a MIDI controller isn’t an original idea, either. But it sure is fun.

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Reed Organ MIDI Conversion Tickles All 88 Keys

What did you do in high school? Chances are it wasn’t anywhere near as cool as turning a reed organ into a MIDI device. And even if you managed to pull something like that off, did you do it by mechanically controlling all 88 keys? Didn’t think so.

A reed organ is a keyboard instrument that channels moving air over sets of tuned brass reeds to produce notes. Most are fairly complex affairs with multiple keyboards and extra controls, but the one that [Willem Hillier] scored for free looks almost the same as a piano. Even with the free instrument [Willem] is about $500 into this project. Almost half of the budget went to the solenoids and driver MOSFETs — there’s a solenoid for each key, after all. And each one required minor surgery to reduce the clicking and clacking sounds that don’t exactly contribute to the musical experience. [Willem] designed custom driver boards for the MOSFETs with 16 channels per board, and added in a couple of power supplies to feed all those hungry solenoids and the three Arduinos needed to run the show. The video below shows the organ being stress-tested with the peppy “Flight of the Bumblebee”; there’s nothing wrong with a little showing off.

[Willem]’s build adds yet another instrument to the MIDI fold. We’ve covered plenty before, from accordions to harmonicas and even a really annoying siren.

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Raspberry Pi AI Plays Piano

[Zack] watched a video of [Dan Tepfer] using a computer with a MIDI keyboard to do some automatic fills when playing. He decided he wanted to do better and set out to create an AI that would learn–in real time–how to insert style-appropriate tunes in the gap between the human performance.

If you want the code, you can find it on GitHub. However, the really interesting part is the log of his experiences, successes, and failures. If you want to see the result, check out the video below where he riffs for about 30 seconds and the AI starts taking over for the melody when the performer stops.

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