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Digital concertina


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Posted (edited)

Hello, everybody. I stumbled upon this tutorial:

https://www.instructables.com/Make-Your-MIDI-Accordion/

And I had an idea which requires none construction skills, yet much more programming knowledge. My idea: why not use a much superior computer power than an Arduino- something like this:

https://uedata.amazon.com/High-Tech-Place-MoreFine-M1-Finger/dp/B013MNTMYG

to which two numerical keypads would be attached:

https://www.amazon.com/Numeric-Jelly-Comb-Portable-Computer/dp/B01E8TTWZ2

 

5 buttons 3 rows should be enough for the usual button layout

while the bigger ENTER button should be good enough for the "air control" button.

 

Do we have in this community an able programmer?

Edited by Gregor Markič
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Interesting ... i had a Roland FR18 for a brief period, bought it out of curiosity.

Nice was that you could program it in all sorts of custom tunings.

 

But as a rock guitar playing friend once said about synthesizers; some are really nice, but still a doorbell.

You press a button and you get a (beatiful?) sound. That's also the case with this apparatus.

The only synth i ever had capable of emulating something acoustic was a Yamaha VM synth, controlled by an Akai Wind controller. The VM was monophonic so you'll never get a double note out of it.

Produced great sax and harmonica type sounds. This Roland FR18 sounded like it's looks; plastic.

 

 

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6 hours ago, Gregor Markič said:

Do we have in this community an able programmer?

 

Actually, the programming/Software part is a complete no brainer. With today's computing infrastructure, you can build the IT part for pretty much ANY instrument with neglectable computer knowledge in lass than a day's work and with < 50 EUR/$/BPs worth of investment.

 

The interesting/challenging part is to build the mechanics. I've worked at it for about four months now (not full time, fortunately) and still struggling.

 

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One thing to watch for is whether that keypad will have key ghosting issues or not. I know that's common on full keyboards, and I assume it's the same for numeric keypads as well. Not an issue if you're only playing melody, but it could prevent certain chord patterns.

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1 hour ago, schult said:

One thing to watch for is whether that keypad will have key ghosting issues or not. I know that's common on full keyboards, and I assume it's the same for numeric keypads as well. Not an issue if you're only playing melody, but it could prevent certain chord patterns.

 

Yep, one of the trap doors I fell into... we should have discussed this a month earlier... 😏 anyways, ghosting can be countered with Zener diodes in every matrix cross point. Other issues are not that easy to solve...

 

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On 5/20/2021 at 1:59 PM, RAc said:

 

Actually, the programming/Software part is a complete no brainer. With today's computing infrastructure, you can build the IT part for pretty much ANY instrument with neglectable computer knowledge in lass than a day's work and with < 50 EUR/$/BPs worth of investment.

 

The interesting/challenging part is to build the mechanics. I've worked at it for about four months now (not full time, fortunately) and still struggling.

 

Whether it's a no brainer depends on your brain. I did a very little machine code (and I mean machine code, not assembly language) many years ago and I'm a regular user of BBC BASIC, but I would not know how to get an Arduino or any such device to generate either MIDI instructions or sounds directly.

 

I'm currently working on a project with a dedicated interface board http://www.doepfer.de/ctm.htm

 

That can be fed directly by push switches if it's one note per switch, but to reproduce the fingering of an Anglo with two different notes according to whether you're pulling or pushing it needs a board full of relays, which I am now part way through wiring up.

 

I have constructed a rudimentary pair of handles connected to a strain gauge and a bit of electronics to generate the push/pull signal and an analogue voltage proportional to pressure (push or pull) to control the volume.

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37 minutes ago, Richard Mellish said:

Whether it's a no brainer depends on your brain. I did a very little machine code (and I mean machine code, not assembly language) many years ago and I'm a regular user of BBC BASIC, but I would not know how to get an Arduino or any such device to generate either MIDI instructions or sounds directly.

 

 

Hi Richard,

 

the Software is all there for you. You'd need an Arduino Due (because that one has a USB comm interface different from the programming interface). Then query the net for Arduino +USBMIDI (or MIDIUSB), and you'll get tons of sample code that you can modify (no problem if you have programmed before). What you have then is something that you can plug into any USB port of your PC (you won't even need an external power supply as the Arduino is powered by the PC). It will identify itself as a USB MIDI sound card. By shorting pins on the Arduino, you'll get a MIDI play sound command that you can feed into a MIDI synthesizer on your PC. "All that remains after that" is to build the mechanics that short the pins for you when you press your button.

 

All of that will be in my video documentation, but currently it looks as if it'll be a while before I get around to making that. In the meantime, I'll be happy to discuss anything that may be of interest to you either by PM or in the public part of the forum.

 

Granted, bisonoric is an additional level of complication. Once I get to the bellows, I'll add a pressure sensor. It would be possible to evaluate the pressure based on the "resting pressure" to distinguish push from pull.

 

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3 hours ago, RAc said:

"All that remains after that" is to build the mechanics ...

This, plus the bellows and their sensor are the hard parts.

 

I went down this path a few years ago and eventually gave up when I realised that, basically, I would have to build almost every part of a real concertina except the reeds, but with additional electronics. 

 

The switches are a real bear as they have to be able to sustain tens, or even hundreds, of thousands of vigorous pushes without failing or shorting internally.  The only commercially available switches that I could find that could do this job were the Cherry brand switches made for computer gamer keyboards.  But they are too big to make a usable array of switches under the buttons.  I decided that I would need to build a fully functional action board just like the ones in real concertinas and then use a Hall Effect sensor under each pad.

 

Similarly with the bellows.  Even with a very responsive pressure sensor you still need a set of real bellows.

 

I believe that this is the approach that Roy Whiteley at Accordion Magic uses to make his midi concertinas.

 

The only useful thing that came out of this project was that I prised Phil Taylor's concertina sound font out of a moribund Apple compressed file.  A link to the font is in my sig below.  I use it nearly every day in Musescore.

 

 

 

 

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18 minutes ago, Don Taylor said:

This, plus the bellows and their sensor are the hard parts.

 

I went down this path a few years ago and eventually gave up when I realised that, basically, I would have to build almost every part of a real concertina except the reeds, but with additional electronics. 

 

The switches are a real bear as they have to be able to sustain tens, or even hundreds, of thousands of vigorous pushes without failing or shorting internally.  The only commercially available switches that I could find that could do this job were the Cherry brand switches made for computer gamer keyboards.  But they are too big to make a usable array of switches under the buttons.  I decided that I would need to build a fully functional action board just like the ones in real concertinas and then use a Hall Effect sensor under each pad.

 

Actually, I remember reading your earlier very useful descriptions of the task. They were one of the steps towards my decision to use reed switches (not the same as hall sensors) for the contacts. One beneficial side effect was that my concertina still has a reed plate, even though it doesn't make a sound... ;-) Of course I totally agree that "all that remains" is a very crude euphemism, hence the quotation marks!

 

18 minutes ago, Don Taylor said:

Similarly with the bellows.  Even with a very responsive pressure sensor you still need a set of real bellows.

 

Absolutely; if for no ther reason than for the reason to play mimick the arm action. 

 

18 minutes ago, Don Taylor said:

I believe that this is the approach that Roy Whiteley at Accordion Magic uses to make his midi concertinas.

 

The only useful thing that came out of this project was that I prised Phil Taylor's concertina sound font out of a moribund Apple compressed file.  A link to the font is in my sig below.  I use it nearly every day in Musescore.

 

 

I use that too as the sound end of fluidsynth. So your work, even though you yourself never brought it to completion, has helped other projects on their way, which I'm very grateful for!

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I decided to avoid real bellows both for simplicity and because it avoids the problem of running out of air. (That is manageable on a real concertina, of course, but my idea is to have no limit on the length of time in one direction.) I have found some push-button switches that are small enough but I don't yet know how satisfactory they will be.

 

If and when I actually finish the project I will report here on how well or otherwise my ideas have worked.

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On 5/21/2021 at 7:03 PM, Don Taylor said:

I believe that this is the approach that Roy Whiteley at Accordion Magic uses to make his midi concertinas.

 

I confirm that the tina that I had Midi refitted by Roy uses Hall effect sensors on the back of each pad, so no contact switches. Still working well after several years. See https://pghardy.net/concertina/lachenal_30566_midi/lachenal_30566_midi.html

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On 5/20/2021 at 4:08 PM, RAc said:

 

Yep, one of the trap doors I fell into... we should have discussed this a month earlier... 😏 anyways, ghosting can be countered with Zener diodes in every matrix cross point. Other issues are not that easy to solve...

 

Just to be pedantic - zener diodes  definitely aren't required, just plain ordinary diodes 😁

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12 hours ago, wes williams said:

Just to be pedantic - zener diodes  definitely aren't required, just plain ordinary diodes 😁

 

Of course you are right - thanks for pointing that out! ☺️

 

Just because I'm at this right now - another major trap door is the one that concerns magnetic disturbances - I am using reed switches in the matrix points, and as it turns out, already the spring, being made of metallic spring wire, transport magnetic disturbances that make the reeds switch when they're not supposed to. Fortunately there's a working relief: Self-adhesive copper foil in the spring posts (copper finish would be even easier to apply).

 

Slowly getting there... 

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Posted (edited)

Brave man to try to use magnetics! All of the electronic musical keyboards (organs, synthesisers, etc)I've worked on use wire contacts (often gold plated) for switches. These have stood the test of time, and can be easily made and replaced rather like lever springs.

Edited by wes williams
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On 5/21/2021 at 8:03 PM, Don Taylor said:

The switches are a real bear as they have to be able to sustain tens, or even hundreds, of thousands of vigorous pushes without failing or shorting internally.  The only commercially available switches that I could find that could do this job were the Cherry brand switches made for computer gamer keyboards.  But they are too big to make a usable array of switches under the buttons.  I decided that I would need to build a fully functional action board just like the ones in real concertinas and then use a Hall Effect sensor under each pad.

 

 

16 hours ago, wes williams said:

Brave man to try to use magnetics! All of the electronic musical keyboards (organs, synthesisers, etc)I've worked on use wire contacts (often gold plated) for switches. These have stood the test of time, and can be easily made and replaced rather like lever springs.

 

Hi there Wes,

 

thanks for your input! It surprises me a little bit, though, as your statement about the mechanical switches seems to contradict Don's earlier elaborations?

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