3-way Selector?

[bassist001]

So, I recently had a client ask me to build him a 3-way selector for his pedalboard. Basically, he wants to have 3 signal chains on his board. 1 for electric, 1 for acoustic, and one for banjo. Just just wants 1 input cable. He wants to plug in whatever instrument he's using and then select which signal path via one switch. I've gotta say, I'm a little stumped when thinking about it. I thought I could maybe start with a relay bypass switching system. But then I'm stumped from there. I could easily do it with two true-bypass switches. But, He doesn't want to have to punch in a combination to get what he needs. Any thought?

[midwayfair]

He wants to press one switch and have it figure out which of three instruments he plugged in? How does he expect it to be that smart? You definitely can't mechanically make one toggle flip another toggle.

You'd need the relay to reset the other switches when any switch is pressed. I don't have a clue how to do it, but that's the main trick you'll need.

[R.G.]

Radio button (also one-of-N switch). You press one button, it goes to that selection.

There's a one-of-eight switching setup at geofex. One IC and some R/C networks. Works for one-of-three as well, just leave off the other five choices.

[Mac Walker]

4017 decade counter, some circuitry to act as a switch debouncer, and 3 pairs of SPST relays?

Otherwise an 8 pin micro-controller would fit the bill, acting as the incremental counter, with code for the switch de-bouncing, and firing three pairs of SPST relays, using three current sinking outputs?

[armdnrdy]

It can be done with CMOS switching.

I don't have an example for the exact "3" channels that you need to switch between, but I've been working on a circuit comprised of CD40XX ICs which allows the user to switch between channels with two momentary switches. (up and down through the channels)
If either momentary switch is held down then it automatically moves through the channels until you let off of the switch.

I believe that what you need can be achieved without the need for the second "down" switch since it is only three channels.
I have the circuit configured for eight channels so I would have to look at some different switching IC options for just three.


Edit: Mac and R.G. chimed in as I was writing.....you get the picture. CMOS switching.

[garcho]

I've probably misunderstood this... 

Does the select switch have to be a foot switch? If he's willing to plug and unplug on stage he should be willing to bend over and use a SP3T (or whatever) switch.

[He] wants 1 input cable. He wants to plug in whatever instrument he's using and then select which signal path via one switch.

Why? To cut down on stage cable? It seems to me like it would be much better to leave each instrument plugged in to each separate chain and build him a A/B/C/Y box.  

From Small Bear, cheap and small:

[armdnrdy]

After re-reading the first post...it seems as if this guy wants as you stated...three signal chains.

Which I now interpret as switching in and out certain effects (one group for electric guitar, one group for acoustic guitar and one group for banjo)

He'll plug in whatever instrument into the input cable then hit the one selector footswitch to choose the correct group of effects.

Is this correct?

[slacker]

I read it as one input into any one of three outputs, but could be into any one of three loops.
Either way, rotary switch for the win, unless he insists on something he can stomp on.

[bassist001]

So, the box basically needs three outputs (cause it's going into three different channels at FOH) and one input. So, the same cable can stay plugged in, without replugging at the pedalboard. Also, one switch to cycle through the three outputs (not have it magically figure out with one you want  ). I did find the Radio button yesterday in my research. But, the sight that I was looking at, made it look like I needed to do some crazy code. So I kind of dropped that one quick haha. I'll look into that some more! I'll check out a 4017 too! Thanks!

[R.G.]

Code? The geofex stuff was hard logic, pretty much all one 74HC373 transparent D-latch.

[garcho]

All this work researching, designing and building something that ultimately will result in your friend plugging and unplugging 1/4" cables, on stage? No offense, but that seems so misguided.

[bassist001]

Well, I don't really care that it's a lot of work (a lot of new ideas wouldn't be around if no one took the time). I'm thinking that I might try and program a Atiny 45 or something to just control some relays. I've done some similar code a while back, and that might be one of my easier ways to go. Plus leaving it open for modifications in the future.