MIDI Organ Pedals

I spent many days and hours on the phone with dozens of music shops, churches, ads in the local Buy & Sell papers, eBay, etc. As a last ditch effort, I went on eBay to see if I could find this beast. I found someone selling assorted parts from a dismantled pipe organ, and I noticed this fellow was from my city as well. I sent him an e-mail detailing what I was after and if he knew of anyone who could help me out. He sent me an e-mail back and said that he had an old AGO 32 pedalboard mechanically intact, as well as the bench to go with it.

It turns out the fellow repairs organs and had acquired an old console, footpedals and all, and had the works stashed in his garage for a few years and was looking for someone to take it off his hands. Turns out it was gutted from a real pipe organ built sometime in the 1950's.

So naturally, I had to clean it.

I took a bucket full of soap and water and had to scrub off five decades worth of dirt, grime and bugs. The thing was filthy to the nth degree. I even had to 'floss' between each pedal with a rag, and the bucket was pitch black after I was done. It took several hours.

The second piece that came with the pedalboard was a long contact plate with little flexible metal poles, likely used at one time in the original organ console as switches to create an electric circuit. All with grime caked on. I had to clean each contact with rubbing alcohol and Q-tips several times. There were 4 contacts for each note. 32 x 4 = 128 contacts.

The original wiring was way too difficult to decipher, not to mention brittle and grimy, so I cut it off and left the contacts as solder points for later.

The next step in the project was to find an economical way of retrofitting the electronics. I found the cheapest piano keyboard I could find that had MIDI output. I found this little gem, and it's perfect. For $40 including shipping, I got this little 3 octave Reveal MusicStar MIDI controller off eBay.

In its simplest form, all you have to do is wire each note to each respective contact on the contact board and wire the returns to the appropriate return points.

Expensive keyboards' circuitry is much more complicated and would not be well suited for this application. They have touch-sensitivity which means variations in how hard or soft you hit a key produces louder or softer notes. That's not what we want for a pedalboard. Cheap keyboards, on the other hand will often have static velocities: the volume of each note is always the same because they do not have any circuitry measuring the velocity of key presses. They simply close a circuit and trigger a note. A larger keyboard would have been more expensive, and much too large for this purpose.

The four buttons attached to the keyboard let you transpose up or down, as well as change the output program # or channel # if needed.

The architecture is also perfectly suited. If you notice, the pedalboard is 2.5 octaves and the keyboard is 3 octaves, both starting on C. The extra notes can optionally be wired to additional controller buttons at a later time that could be mounted on top of the pedalboard to perform programmed functions.

Here you can see the contact board roughly mounted on the backboard with the pedals in correct position. You press a pedal down, and the oddly shaped metal hook comes in contact with the four wires below it, closing a circuit between them all. It was apparent that the pedalboard was designed as a modular piece of equipment, as it was in no way permanently mounted on the chassis of the console. You were able to remove the pedals and even swap them for a different set, it seemed. The pedals clamped onto the backboard with two metal hooks to keep them in place and assure the correct alignment and distance between the contacts.

There is one long metal wire spanning the entire length which is soldered to the fourth wire of each contact, in case the electronic schema calls for such a requirement in circuity. In my case, I was able to use this to my advantage because of how the electronics in the little keyboard were designed.

I was able so source some cheap wiring by stripping apart an old IDE cable. After removing the two connectors, both ends were bare and ready for soldering. Its length was perfect for the job.

After working for a few hours each day over the course of a week, I had all the wiring soldered and the entire unit tested without a flaw.

The wiring got out of hand as I approached completion of the soldering, and I tried to restrain it with little twist-ties.

For a test run, I put it all together and propped the faux console up with whatever I could find around the living room. (Computer is located just out of view to the right)

The "finished console" after the project's completion:

This is an old photo :)

 

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A Fun Retail Products Comparison

	Roland PK-25 25-note pedalboard MSRP: $4000.00+
	Classic MIDI Works 32-note pedalboard MSRP: $1389.00
	Do-It-Yourself Retrofit 32-note pedalboard: $75 MIDI circuitry: $40 Total:   $105

 

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Links

I'm not the only one to cook up a project like this!
Take a look at other people who have attempted the same thing with varying complexity:

Hauptwerk
Laukhuff's Portable MIDI Organ Pedals
Stephen Malinowski