organ

39 Articles

Ask Hackaday Answered: The Tale Of The Top-Octave Generator

August 22, 2018 by 57 Comments

We got a question from [DC Darsen], who apparently has a broken electronic organ from the mid-70s that needs a new top-octave generator. A top-octave generator is essentially an IC with twelve or thirteen logic counters or dividers on-board that produces an octave’s worth of notes for the cheesy organ in question, and then a string of divide-by-two logic counters divide these down to cover the rest of the keyboard. With the sound board making every pitch all the time, the keyboard is just a simple set of switches that let the sound through or not. Easy-peasy, as long as you have a working TOG.

I bravely, and/or naïvely, said that I could whip one up on an AVR-based Arduino, tried, and failed. The timing requirements were just too tight for the obvious approach, so I turned it over to the Hackaday community because I had this nagging feeling that surely someone could rise to the challenge.

The community delivered! Or, particularly, [Ag Primatic]. With a clever approach to the problem, some assembly language programming, and an optional Arduino crystalectomy, [AP]’s solution is rock-solid and glitch-free, and you could build one right now if you wanted to. We expect a proliferation of cheesy synth sounds will result. This is some tight code. Hat tip!

Squeezing Cycles Out of a Microcontroller

Let’s take a look at [AP]’s code. The approach that [AP] used is tremendously useful whenever you have a microcontroller that has to do many things at once, on a rigid schedule, and there’s not enough CPU time between the smallest time increments to do much. Maybe you’d like to control twelve servo motors with no glitching? Or drive many LEDs with binary code modulation instead of primitive pulse-width modulation? Then you’re going to want to read on.

There are two additional tricks that [AP] uses: one to fake cycles with a non-integer number of counts, and one to make the AVR’s ISR timing absolutely jitter-free. Finally, [Ag] ended up writing everything in AVR assembly language to make the timing work out, but was nice enough to also include a C listing. So if you’d like to get your feet wet with assembly, this is a good start.

In short, if you’re doing anything with hard timing requirements on limited microcontroller resources, especially an AVR, read on!

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Vintage Organ Donates Parts For Two New Instruments

May 27, 2018 by 8 Comments

It’s often hard to know what to do with a classic bit of electronics that’s taking up far too much of the living room for its own good. But when the thing in question is an electronic organ from the 1970s, the answer couldn’t be clearer: dissect it for its good parts and create two new instruments with them.

Judging by [Charlie Williams]’ blog posts on his Viscount Project, he’s been at this since at least 2014. The offending organ, from which the project gets its name, is a Viscount Bahia from the 1970s that had seen better days, apparently none of which included a good dusting. With careful disassembly and documentation, [Charlie] took the organ to bits. The first instrument to come from this was based on the foot pedals. A Teensy and a custom wood case turned it into a custom MIDI controller; hear it in action below. The beats controller from the organ’s keyboard was used for the second instrument. This one appears far more complex, not only for the beautiful, hand-held wooden case he built for it, but because he reused most of the original circuitry. A modern tube amp was added to produce a little distortion and stereo output from the original mono source, with the tip of the tube just peeking above the surface of the instrument. We wish there were a demo video of this one, but we’ll settle for gazing at the craftsmanship.

In a strange bit of timing, [Elliot Williams] (no relation, we assume) just posted an Ask Hackaday piece looking for help with a replacement top-octave generator for another 1970s organ. It’s got a good description of how these organs worked, if you’re in the mood to learn a little more.

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Ask Hackaday: How Do You DIY A Top-Octave Generator?

May 24, 2018 by 157 Comments

One of the great joys of Hackaday are the truly oddball requests that we sometimes get over the tip line. Case in point: [DC Darsen] wrote in with a busted 1970s organ in need of a new top-octave generator, and wondered if we could help. He had found a complicated but promising circuit online, and was wondering if there was anything simpler. I replied “I should be able to get that done with a single Arduino” and proceeded to prove myself entirely wrong in short order.

So we’re passing the buck on to you, dear Hackaday reader. Can you help [DC Darsen] repair his organ with a minimum amount of expenditure and hassle? All we need to do is produce twelve, or maybe thirteen, differently pitched square waves simultaneously.

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The Furby Organ

The Furby Organ

February 12, 2018 by 30 Comments

Sometimes you have an idea that is so brilliant and so crazy that you just have to make it a reality. In 2011, [Look Mum No Computer] drew up plans in his notebook for a Furby organ, an organ comprised of a keyboard and a choir of Furbies. For those who don’t know what a Furby is, it’s a small, cute, furry robotic toy which speaks Furbish and a large selection of human languages. 40 million were sold during its original production run between 1998 and 2000 and many more since. Life intervened though, and, [LMNK] abandoned the Furby organ only to recently take it up again.

He couldn’t get a stable note out of the unmodified Furbies so he instead came up with what he’s calling the Furby Forman Fusion Synthesis. Each Furby is controlled by a pair of Ardunios. One Arduino sequences parts inside the Furby and the other produces a formant note, making the Furby sing vowels.

We love the label he’s given for what would otherwise be the power switch, namely the Collective Awakening switch. Flicking it causes all 44 (we count 45 but he says 44) Furbies to speak up while moving their ears, eyes, and beaks. Pressing the Loop switch makes them hold whatever sound they happen to be making. The Vowel dial changes the vowel. But you’ll just have to see and hear it for yourself in the videos below. The second video also has construction details.

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SID Organ Pulls Out All The Stops

January 2, 2018 by 15 Comments

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

October 15, 2017 by 6 Comments

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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Wind Chimes And Dry Ice Make An Unusual Musical Instrument

September 19, 2017 by 29 Comments

When it comes to making music, there are really only a few ways to create the tones needed — pluck something, blow into something, or hit something. But where does that leave this dry-ice powered organ that recreates tunes with wind chimes and blocks of solid CO2?

It turns out this is firmly in the “hit something” camp, as [Leah Edwards] explains of her project. When the metal wind chime tubes come in contact with dry ice, the temperature difference sublimates the solid CO2. The puff of gas lifts the tube slightly, letting it fall back against the brick of dry ice and making a tone. The process is repeated rapidly, providing a vibrato effect while the tube is down. [Leah] used solenoids to lift the tubes and, having recently completed a stint at National Instruments, a bunch of NI gear to control them. The videos below show a few popular tunes and a little bit about the organ build. But what — no songs from Frozen?

We can easily imagine this same build using an Arduino or some other microcontroller. In fact, it puts us in mind of a recent reed organ MIDI project that has a few ideas to offer, like ways to quiet those solenoids.  Continue reading “Wind Chimes And Dry Ice Make An Unusual Musical Instrument” →