SID Organ Pulls Out All the Stops

Someone left this organ out in the rain, but [Tinkartank] rescued it and has given it a new life as a SID controller. What’s a SID, you ask? That’s the sound chip Commodore used in the C64, a remarkable chip revered among retro gamers that was way ahead of its time.

He threw out everything but the keyboard assembly for the build. Each key press now drives a momentary button, and those are all wired up to an Arduino Mega through some I/O expansion boards left over from another project. The Mega drives the MOS6581 SID chip which generates those sweet chiptunes. There are four CV outs for expanding the organ’s horizons with Eurorack modules.

Our favorite part is the re-use of the stop knobs — particularly that they are actuated the same way as before. The knobs still technically control the sound, but in a new way — now they turn pots that change the arpeggio, frequency, or whatever he wants ’em to do.

The plans for the future revolve around switching to a Teensy to help out with memory issues. Although it’s a work in progress, this organ already has a ton of features. Be sure to check them out after the break.

Once you dive down the chiptunes rabbit hole, you might want to take them everywhere.  When you get to that point, here’s a portable SID player. A SIDman, if you will.

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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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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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