DIY CV video mixer?

[colossus]

Anyone know if adding CV control to a simple Klomp-style video mixer is doable?

This is his really simple schem: http://www.karlklomp.nl/pro/dirtmx/dvmschema.jpg

My idea is to just replace the pot with a vactrol or LED/LDR but my fear is that 1K is relatively small compared to the resistance of a typical LDR. Thoughts? Does this seem doable? I'm waiting on some RCA jacks to come in so this is kind of a pre-experimentation question.

[x-posted at MuffWiggler]

[crochambeau]

In that scheme the pot is wired as a very primitive mix with wiper as output between the two channels.

So, it functions by changing the position of the center element.. and LDR has only two elements, so in order to emulate a pot hooked up as a voltage divider you'd need two LDR, with one increasing while the other decreases. It's sound in theory, but you're going to have a hell of a time getting then to track worth a shit, especially if 1K is an important target.

You're looking to mix analog video signals? You're aware of frame sync issues I trust.

I haven't looked in a while, but the resale value of an analog video mixer PLUMMETED with the transition to HD a while back. I picked a few up for a fraction of what it cost to ship them, a good search term is SEG or Special Effects Generator. Such a tactic would not resolve your desire for CV, but you might be able to sink the video signal to ground on each channel via the vactrol if it's not a 75 ohm line.

[colossus]

Ah, damn. I knew this was going to be more complicated than I had originally envisioned. I'll look into other analog mixers...I just really want to get CV working. The idea of a really slow clocked fade just makes me . I imagine I could probably get a CV to midi module and then that roland midi mixer but that's just a bit more than I wanted to spend. Thanks for the help though! Once the parts come, I'll fool around vactrols and see what I can do, but I'm not expecting much.

[lordgalvar]

Why not control a CV PWM motor with CV and then just adapt that to turn the knob? Make it all mechanical instead of electrical?

Then you could probably just use an arduino to control the knob from a number of sources, pots, sensors...(or just do it all analog too).

[colossus]

Yeah, I was actually thinking of something like that, it's just a matter of figuring out how to interface a knob with a motor. If anyone has ideas, I'm all ears.

[Dr. Sherman Sticks M.D.]

bet lego has something for that

[lordgalvar]

bet lego has something for that

Op-1 style...

Thought of that this morning when walking around haha...good lookin' out Dr.

I was going to say to check out battlebots builds and/or general arduino project s...but legos