StompLFO Test Board

[culturejam]

I hesitate to call this a "dev" board because it's not really designed for rapidly testing code. It's really just for being able to diddle with the main parameters of the StompLFO from Electric Druid, which is a really cool LFO-on-a-chip with tap temp baked in. It's got 8 waveforms, including two that are pseudo-random. The code is open source, so you can modify it to suit your needs should you desire. That's beyond the scope of this post, but we could talk about that later if anyone is curious.



So this board has all the necessary components to get all the functionality out of the stock StompLFO code. And I also added a few things that make it easier to dial in and use it with some flexibility for breadboard projects or other types of circuit testing. I added two switches (using header pins and 2-pin mini jumpers) for 1) changing the microcontroller offset pin to either high or low state, and 2) bypassing or enabling a second set of LED pads that can be run off board to a breadboard or whatever. I also added a trimmer to set the minimum speed of the LFO because it can go slower than useful for some effects. Voltage regulator is also included to make it a self-sufficient package.

So that's what I've been goofing around with the last couple weeks (months, actually, if I'm being honest), among other things. I've also modified the code a bit so that the chip has only the waveforms I want and in the order I want in regards to the Wave pot sweep. Took a bit of monkeying around, but it's not real hard to do.

[Aleph Null]

Looks nice! Do you have any projects in mind to use this as a platform for?

[culturejam]

Looks nice! Do you have any projects in mind to use this as a platform for?

Thanks!

Yes, I have a tremolo and vibrato-phase-thing nearly complete. And I'm spitballing a filter effect and also want to use it as the modulation for a PT2399. Oh, and I want to do my own version of the 4MS Phaseur Fleur (6-stage optical).

[jimilee]

Looks nice! Do you have any projects in mind to use this as a platform for?

Thanks!

Yes, I have a tremolo and vibrato-phase-thing nearly complete. And I'm spitballing a filter effect and also want to use it as the modulation for a PT2399. Oh, and I want to do my own version of the 4MS Phaseur Fleur (6-stage optical).

That would be awesome! I built that phaser myself.


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[jwin615]

Awesome stuff.
I've wondered how hard it would be to change to code to get one of those detent pots to work.
Unfortunately, i.coulsnt find an 8 detent pot, only 10+. Of course, if you are only using 5 waveforms, I suppose you could range each one to two detents on a 10 detent pot.

Oh. Just found this one with 6 detents.
https://syntaur.com/Items.php?Item=11133

[culturejam]

Awesome stuff.
I've wondered how hard it would be to change to code to get one of those detent pots to work.

It actually works fine without a detent pot. Normal pot is okay, it's just that you have to pay attention to when the waveform changes by looking at the indicator LED. It sucks for all 8 waveforms, but if you have 5 or less, it's quite manageable. You could also use a rotary switch with some diodes to get the right voltages, or if you only want 2 or 3, you could use a simple toggle switch and diodes (or even just resistors). Again, that gets easier if you pare down the number of waveforms.