Civilizing a 1971 church organ

Post your projects. Pictures, code, and bragging welcome.
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Joined: Mon May 03, 2010 9:19 pm

Civilizing a 1971 church organ

Post by ke9tv »

I realize that I never posted last summer's fun project here, and considering that it uses two RBBB's, I figured that at least the Modern Device folk might be interested.

Last spring, I went out and bought a nearly-40-year-old electronic church organ. It was enough of a period piece that its voicing was controlled by IBM cards - remember them? - and the organist who had owned it had a collection of a few hundred of them. Well, this system had a few drawbacks:

I had to keep the cards in order and hunt through the file to find the voices I wanted.

The cards, being 40-year-old paper, were starting to disintegrate.

Well, just after moving the organ into my house, one of the lamps in the card reader burnt out. I decided that changing out little incandescent lamps was going to be another annoying maintenance idem, and decided to replace them with LEDs (which, after all, last nearly forever). Well, as I was doing this, a light bulb came on over my head. :idea: (No, this is 2010, an LED came on over my head, and someone should update that emoticon!) I could solve the other two problems at the same time by firing the LEDs as if a card were moving through the slot.

A bunch of hackery later (reverse engineering the card code, figuring out how to digitize the cards without messing with the old electronics, that sort of thing), I had a keypad and display sitting on top of the organ letting me choose stops. Much more convenient than sticking IBM cards in a slot. It's built around a 4x20 LCD display, a telephone keypad, and an RBBB making a display terminal, and another RBBB inside the organ as an LED driver. Build log with details and lots of pictures start at ... eader.html.

As one colleague observed : "I get email all the time offering to revitalize an aging organ, but you've actually gone and done it." ;)