MIDI to hardware question.

[CatalinaWOW]

I have for some reason decided to build a calliope.  If you google the Kerr Calliope you can see the general idea.  I am updating this to take advantage of 3D printing and a "better" way to make the sound pipes.  The fundamental need is to take a midi data stream and drive a single solenoid for each of 44 pipes.   MIDI isn't complex and I could draw up a board with an MCU and a handful of data latches to handle this, but I really want to focus on the electro-mechanical parts of this project.   I would just prefer to buy something.  Kerr used a product that doesn't seem to be available any longer.  Not surprising after 20 plus years.  My google foo has been insufficient to find anything similar.

Can anyone suggest a currently available product?

[pqass]

If you're okay with DIY Arduino/Teensy (or other MCU) then see here (halfway down the page).  It's church-organ proven!

I'm sure the beginner coding can be collapsed into three loops taking up only a page.

It looks like the MIDI library used is this one.

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Fixed the link.

[MarkF]

Do you know how much air flow would be required for the biggest pipe?

Here's a couple ideas:

• https://tinkersphere.com/motors-wheels/2830-solenoid-air-valve-12v.html
  This is a small solenoid where the air flow opens are probably too small.  But you could possibably 3D print a value cone with a gasket glued on that would go over the metal actuator.  There may be better solenoids that you could 3D print the valve assembly.
  
  
• https://www.sparkfun.com/12v-solenoid-valve-3-4.html
  Here is one for water that would probably allow enough air flow???

It's an interesting project since I was a church organist in my younger years.

[MarkF]

Instead of a plunger style valve, may be a sliding valve would be easier to manufacture.

[themadhippy]

midi to dmx convertor and 44 dmx relays?

[CatalinaWOW]

midi to dmx convertor and 44 dmx relays?

This may be the google search term I was looking for.

[CatalinaWOW]

MarkF.

I don't know the airflow.  But know from the Kerr article that about 4 inches of water manifold pressure is desired (about 0.15 psi or about 0.01 bar).  The Kerr article also gives the throat sizes he used.  I used those for guidance.   The limitation of the Kerr design is that he was forced to compromise on pipe diameter by the limited available stock sizes.  He also chose not to individually select the flow limiting throat diameter.  3D printing and using rolled tubes of thin aluminum flashing allows avoiding those compromises and makes fabrication easier.  I have built a test pipe and it works fine blowing through it with my mouth.  I have also printed the valve and valve seat and they seal amazingly well.  The cheap solenoids I plan to use arrive next week (that is the latest promise, the original promise was last week) and I will be able to verify that the forces and throw work out.  The calculations say they will, but the proof will be  in the pudding.

This weeks project is finishing the design and fabrication of a small 3D printed slip roll to make rolling the flashing into tubes easier.  The test pipe was hand formed around a pipe.  It doesn't have to be perfect, the tubes are clamped between external rings and internal forms.

If I am forced to roll my own controller the architecture I plan is to make a tiny board with pass transistor or FET and commutating diode to attach directly to the solenoid.  Power and ground bussed through all the pipes leaving only a signal wire to go to each local drive board.  Then a control board with 6 8-bit latches, an MCU to read and decode the MIDI input and necessary power and I/O support for USB receipt of .mid files.  Have just started a survey of MIDI software libraries.   This control board and associated software is the part I want to avoid.  I can do it.  It isn't a huge job.  But I am not motivated at the moment.