Saturday, September 5, 2009

Allen organ project - proof of concept achieved. Facepalm.

Now that the LED control is integrated with the card reader, it's time to see if it actually can program a stop!

Open up the organ, and in it goes. Take the breadboard display terminal, select "Blockflöte 8'" and send it over.

WOOHOO! First try!

Try again - Octa-Bell. "Bing bong bing." Kinura. "Blaaaaat." Festival Trumpet. "ta-ta-ta-DAAAA!"

Time to close up the organ and work on suitable packaging for the terminal.

Oh dear. Oh dear. Oh [Nixonian expletive deleted].

The two rotary switches above the card reader leave absolutely no clearance behind the lamp strip.
There's no room for the rearward extension of the board.

Oh dear.

Fortunately, there's plenty of room underneath the card reader. Back to the bench.

I cut the card reader perfboard in half, and rewire everything so that I have two halves joined with a strip of ribbon cable. I'm a little worried about switching noise getting into the audio, so I try to control it some by having each LED have an independent ground return on an adjacent conductor. (Desolder all the LEDs and resistors. Solder in both ends of all 20 conductors of the ribbon cable. Replace the LED that I overheated in the rework process.)

After all this rework, Frankenreader goes back in the organ and looks like this:

Frankenreader - rear view
From the rear. The logic board extends a little way under the reader.

Frankenreader - top view
From the top. The ribbon cable clears all the hardware above.
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