Arduinill

Here, have some PCBWay deja vu.

That’s the new version of dac/ino, the one with the op amp connection not drawn by a chimpanzee. And it works. CV outputs come out as they should, 0–10V or ±5V depending on jumper settings. (The latter is actually more like -5.039 to 4.962V, and I think I have some idea why, maybe. But I’m not much concerned with that at the moment.)

On close examination you can see some other changes. The solder pads for additional digital and analog pin access have become footprints for pin headers, and two other pin headers have been added as well — they connect to the six gate and CV inputs/outputs, respectively, and to Vcc and ground. The idea is that it gives you the possibility of creating a daughterboard with board-mounted panel components instead of having to run everything through Molex.

The circuit’s very modular, so you don’t have to populate inputs and outputs you aren’t using. For initial tests I populated only the Arduino, power components, the DAC, the voltage reference, the op amp, and associated components for one CV output. (I actually left out a resistor I should have included, but it didn’t seem to make much difference.)

Once I saw the CV out working, I went ahead and filled in most of the rest. I did leave out one gate out and the Molex connectors for CV In B and D.

The panel’s a reject, made for the expression pedal interface but not used due to some badly lined up holes. Yes, I can be a bit anal. Anyway, it was a good way to anchor three jacks, which in this case were plugged into a Gate In, a Gate Out, and a CV In. I loaded up software to make it behave as a clock divider, with the division rate governed by the input CV. It worked.

Later I switched the Gate In jack over to CV Out A and loaded a sketch for a simple CV quantizer. (I wasn’t using the Gate Out.) That worked too:

So I think this thing’s doing what it should do, more or less. I’ve got a plan for what to do permanently with this particular board, and maybe I’ll make a couple more just for whatever I need at the moment.

The dac/ino GitHub repository is here: https://github.com/holmesrichards/dac_ino.

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