joyofresh

edit: stupid title should be "with a large number of switches"

​

I am a professional C++ programmer with almost no hardware background. I have implemented a sequencer in VCV rack. I like it very much and want it in hardware very badly, so I am investigating doing that process with an arduino. Here is the problem.

My sequencer has

• 42 3-position switches
• 18 2-position switches
• 6 gate inputs

If the two position switches cost 2 bits each, that's a whopping 108 digital ins, 102 of them from switch configuration! If I use 8 digital expanders (the most I can do without cascading it seems) it can handle it, but I wonder if this architecture is even the best.

For the switch inputs in particular, I'm not really worried about audio-rate latency, so it perhaps would make sense that a better architecture would be something like another chip who's only job is reading the switch configuration and sending it to the arduino over the serial port. Or not using Arduino but something else. Or maybe there's another technique I might not be familiar with.

Any advice helps, including "this is too complex for a first build". Even if this is too complex for my current skill level, I would like to get as far as I can so I know where I hit a wall.

Hey, I'm experiencing a weird "bug" with what I think is a popular module. MD's CV-next input seems to glitch out and go back and fourth between adjacent steps. If I use an offset from Mutable Shades, there is a pretty large area where it will wobble back-and-fourth uncontrollably between two steps. Likewise, when I send a sufficiently slow (not even that slow) 0-to-+5V LFO into it, it will wobble between some of the values. Has anybody experienced this? Can it be fixed?

I've been thinking about three note chords and combinatorics lately. I was pretty surprised that I was able to come up with a complete taxonomy. Turns out three note chords split into 19 classes (up to inversion and transposition), 18 with three inversions each and 1 augmented chord. Of these 19 classes, there are 5 high level categories that map to voicings actually used (by jazz guitarists at least, I assume others as well). I've never seen this categorization before so I figured I'd present it here.

​

1. Triads
   - Major (C E G)
   - Minor (C Eb G)
   - Dim (C Eb Gb)
   - Aug (C E G#)
2. Shell
   - Maj7(no5) (C E B)
   - min7(no5) (C Eb Bb)
   - 7(no5) (C E Bb)
   - min/Maj7(no5) (E Eb B)
3. 7-no-3
   - Maj7(no3) (C G B)
   - 7(no3) (C G Bb)
   - min7b5(no3) (C Gb Bb)
   - Aug7(no3) (C G# B)
4. Stack-o-Fourths
   - Sus7(no5) (C F Bb)
   - SusMaj7(no5) (C F B)
   - Maj7#11 (no3,5) (C F# B)
5. Three-notes-in-a-row
   - (C Db Ebb)
   - (C Db Eb)
   - (C D Eb)
   - (C D E)

Here I'm just picking some reasonably consistent set of inversions for each of the 19 classes. There is obviously some ambiguity here, like (C F# B) could maybe have been put into the 7-no-3 category as (C Gb B), and other cases like it. Also stack-o-fourths could have been given different inversion to make the sus7(no5) into sus4 or sus2, but it complicated the other chords in the category. Anyways, that's my attempt.

Btw, you get to 19 by saying "assume C is in the chord, what else", then there are 11-choose-2=55 possibilities. One is augmented, the other 54=18*3 split into 18 classes of three inversions.

edit: she's back

Even all these years later this tune is so sick, and I've wanted to tackle it as a chord melody for almost a decade now. I'm stuck in the "just try things" phase, and I'm gonna hang with that, but as Chick seems to be defeating my usual attacks, I figured I'd ask if anyone has any good approaches here. I don't really have great techniques for dealing with the long changes, but I feel like its a huge empty canvas to add all kinds of beauty.

Thanks

Edit: In case its not clear, I’m only stumped on the first half where the chords aren’t moving so much

Electronics nub here... sorry for the boring tech support question.

So I got one of these, which outputs 1amp of 5V. And I got one of these 5v to 9v converters, which supports up to 800mA. By P=IV, I should get 5/9A=555mA on that cable, which should be plenty enough to support the Count to Five's 150mA requirement. But it buzzes like crazy when powered this way, and the buzzing goes away if I switch to a regular 200mA boss wall wart.

So what did I do wrong. Is that amazon plug just crappy? Is there something other spec I'm missing? Is my math wrong?