Expression Pedal for stompbox

[jishnudg]

I used to own one of these

https://drive.google.com/file/d/0BwMVia471c4SWUFXVmFic0QzU1E/edit?usp=sharing

I always liked the expression pedal function on these units (and many other digital multi effects in the same range) where you could select what the expression pedal would be used for...lately I've been wondering if I can hack an analog pedal to have this functionality...say I have an overdrive pedal with 4 pots (gain,volume,bass,treble), and I install an exp. pedal out into the enclosure....what would I need to do to,say, add in a push-button that cycles between the following settings -  1. no exp. pedal 2. exp. pedal controls gain ie exp. pedal pot replaces the gain pot 3. exp. pedal pot replaces the volume pot    ....etc etc . I'm assuming that all the pots on my pedal have the same value, 100k or something.
I'm pretty sure this can be done with CMOS...probably would be five minutes worth of work with a uC but I know absolutely nothing about uC and am yet to check them out...

Any ideas? Has anyone tried this out?

[duck_arse]

erm, a rotary switch, a 100k resistor with an ldr in parallel. switch changeover the pot with the ldr/R, and expression-pedal the led driving the ldr.

[jishnudg]

Yep rotary switch would do it; you're right - - - but any leads on the possibility of using CMOS switching? would love to have a small microswitch do it

[duck_arse]

not cmos switching as such, but switching with cmos, at least. have a look here, see if anything useful. you can be the first to reply in that topic, bonus!

http://www.diystompboxes.com/smfforum/index.php?topic=106502.0

[jishnudg]

Oh,man...wow. Okay give me a minute (or a day or two) to get my head around this...