The definitive MIDI controller | This is not rocket science

Protosynth panel progress

Christmas came and passed, and I’ve been busy working on the panel. And there is indeed progress!

Front panel prototype

I was so excited to see how the red front panel design would turn out, with all the graphics and all. The shipping was not so smooth this time, yet it still only took three weeks from the order for the finished boards to arrive from ITead. The quality of the boards is high, as good as ever: just perfect.

There’s only one problem… these boards aren’t red!

Panel front

Uh-oh. Somebody messed up my order, and now I have a bunch of green boards instead. These aren’t good at all for a translucent plexiglas box, as the green color would just make the whole setup look like a very early prototype, instead of the soundbox-to-get-your-hands-on that it is. ;-)

Luckily Stijn was there to cut me a very nice panel out of thin MDF – thank you! It fits perfectly, and I can still paint it red. Maybe I could make a full box out of this stuff, instead of just a pair of sheets for mounting the prototype… Heck, this might still turn out very nice!

It’s surprisingly difficult to mount all the controls on a single board in such a way that they end up level on the top of the panel and not sticking out too far. The reverse through-hole potentiometers are perfect for this. The encoders can be mounted the same way, albeit only by bending the pins carefully.

The led power supply regulator is still missing in the picture below. It seems to be necessary as I expected: the leds can easily suck enough current to cause the 3.3V level to droop, at least with the relatively weak Arduino power supply that I used for the first tests. And when that happens, each and every potentiometer will momentarily change in value, yuck.

But it works, everything works!

Panel back

With the separate 9V power supply, and a bit of hacking, it took no time to get the board up and running. All knobs work, all buttons work, all encoders work, and all leds work. The joystick works, too. And the ATmega48 is more than sufficient for all this. Awesome!

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