One grand MIDI encoder or several

[farnsy]

I'm about to embark on the conversion of a 3m non-working Rodgers into a VPO. I'm also replacing all the keyboards with Allen keyboards while I'm at it so I'm going all the way to the bones. I'm beginning to acquire the necessary parts and I have a question:

Is there an advantage to building a single MIDI encoder to run all three manuals and the pedals (and stops, I guess) or does it make more sense to have separate encoders for various items?

If I wire it in octaves (12 notes), I will need a total of 30 pins for the manuals and pedals (12 chromatic notes) + (5octaves*3manuals) + (3 octaves on the pedals) = 30. I would stick the top C's in with the pedals if I was trying to save pins but more likely just use one extra for them. I could accomplish all this with, for example, a Teensy 3.5 (58 pins) with plenty to spare for expression pedals and stops.

Alternatively I could use a separate encoder for the pedals, one for each manual (or for the three manuals) and a separate one for stops. As far as I know there's no problem with having several USB MIDI devices connected at once while using Hautpwerk or Organteq.

Is there any advantage or disadvantage to doing one approach versus the other? Using more than one will involve buying more hardware but these devices are only $25-$31 so it's not a big deal.

What do you think? Anything I'm overlooking?

[jbird604]

Sounds like an amazing project! We'll need pics and details of course.

Personally, I'm all for simplicity whenever possible. My VPO project involves a ready-to-go MIDI encoder with note by note and switch by switch inputs for the keyboards, pedals, pistons, and stops, but that's mainly because I already had this encoder, a remnant from another MIDI organ project from another hobbyist. But if I were starting from scratch today, I'd be looking at similar "full console" encoders from the various suppliers. I don't know what all the sources are, but I have bought such devices in the past from Roman Sowa (midi-hardware.com) and they have always worked beautifully. And they are not expensive, so I see little benefit economically in building my own. But your needs and preferences may be entirely different.

I hope that others on the forum with far greater experience in this field than me will offer you some advice. I'm really a newbie at this, even though I have bought a few encoders in the past and helped a customer wire it up to an existing console. I just never went beyond the wiring of it, so I can't help you when it comes to knowing how best to hook it up to the rest of the gadgets.

Good luck!

[farnsy]

I'll definitely post pics and details as I get this underway. My situation and objectives are a little different from yours in that (1) I don't have a lot of parts already (2) I want to have a project where I get my hands fully dirty (including coding up the MIDI encoder) so I will likely take the hard way in a few respects. I actually could have bought an Allen organ with keys already in place or a working one and skipped this but I value the project itself. I'm now experimenting with reed switches for the keys, etc. Gonna be an adventure.

[John Kinkennon]

For a three manual Rodgers you will likely have bus style manuals with a wire for each note. I too would use a single encoder with multiple input boards. These input boards are typically one per keyboard and connect to the encoder using SPI or multiplexed addressing. My choice for an encoder is the Teensy 3.6 which has a lot more speed then necessary. It has enough pins to easily do two SPI channels with perhaps four input boards on each channel. For Rodgers consider 12v keying if it has the phosphor-bronze "whisker" contacts.

[Organkeys Jones]

Re-read farnsy's post - he is replacing the Rodgers manuals with Allen.

[farnsy]

Thanks for your comments!

I considered the Teensy 3.6 but the extra speed is not relevant as far as I can tell. The advantage of the 3.5 is that the pins are all 5v tolerant, so if a knuckleheaded DIY enthusiast (ahem) accidentally connects the 5v pin to one of the digital inputs, there will be no damage to the board. My understanding is that the 3.6 will take damage if those pins get 5v.

Probably neither of these considerations are critical, but I thought since the weak link here is me, I should get the slightly more robust board. Does that make sense?

[John Kinkennon]

Point taken about the Allen manuals. I've had success with the Allens at either 3.3v or 5v. With Allen it makes sense to run them as an 11x6 matrix but they are fine in a bus configuration if they are rewired and have the diodes removed.

[lizny]

I went with a separate controller (itsybitsy 32u4 16mhz which is a 5v logic board) for each manual. It keeps the code simpler and these things are only about 10 bucks. I put a small usb hub inside the organ, and made each controller a different MIDI channel. HW deals with it just fine. I did save a board by running the pistons and toestuds off the swell controller.

[farnsy]

Again, super helpful. Thanks! I wonder if there's a list of which devices do native MIDI over usb somewhere...

[lizny]

I should have been more specific - the ATmega32U4 chip does the magic. If an arduino is based on that chip, it will do USB-Midi. I don't know if there is a list, but that is the specification you need and you can use the MIDUSB Arduino library to talk to it, which makes the whole thing dead easy.

[tbeck]

The Arduino Leonardo functions as a MIDI USB. Teensy 4.0 and 4.1 can as well. Possibly earlier versions can as well but not I'm not sure.

[John Kinkennon]

Since you are using the Teensy 3.5, a great choice, let me get back to the subject of your post. If you decide to use more than one Teensy then it is important to give them different names and different product IDs. The renaming is accomplished with a name.c file and the Teensy web site documents that. Unique product IDs are also required, at least with Windows 10. That is not documented anywhere that I have seen but can be done by modifying library files. I would keep it simple and stick with the single encoder.

[farnsy]

That's extremely helpful to know, and sounds like good advice. Thanks! I'm not stuck on Teensy 3.5, by the way. I haven't purchased anything yet--for now I'm doing demo steps with my Elegoo Uno. Still attempting to live by "plan twice, buy once." I've already had to purchase a second set of magnets because the first ones I got are too weak to trigger my reed switches unless I use two magnets per key. They weren't expensive either, of course, but I don't like buying stuff I don't ultimately use.

Modularity sounds like a good thing in principle but I can't think of an immediate need for it inside my organ.Trying to see if anyone knows of something I missed. I'm also considering using a dedicated board for the pedals so I don't have to run multiple wires up to the console.

[lizny]

Yes this. pile all the manuals you want onto one controller, but save yourself all that wiring. Essentially I have a standalone MIDI pedalboard with a USB port. I could move it to use with another keyboard if I wanted.