What kind of switch....

[ollie]

What i'm looking to do is to have a switch that does something different while it's depressed than it does when it's on.

I.E. OFF>Foot Held Down (effect 1)>ON


I would assume this would be some kind of momentary switch but wouldn't it need to be single pole triple throw?

Any help or advice would be greatly appreciated

[R.G.]

Could you explain the action a bit more?

Did you mean that you want a stomp switch that has three conditions like:

(1) Off
(2) pressed and released, remains ON
(3) pressed from either OFF or ON and held down

There are some interesting questions there, not least of which is does it do the same thing when the switch has been OFF and is pressed and held as it does when it's been ON and is pressed and held, and then what it does afterwards when you release the hold. Does the release from the pressed and held state have to remember which state it was in before being pressed and held, or does it always do the same thing in this case, and if so what?

[ollie]

Thanks for the quick reply

It will probably do the same when pressed and held from the on state and from the off state but I would only plan to use it for going from off to pressed.

What I was thinking was to do something in a similar vein to the weapon pedal. Obviously I'd only use one effect rather than blending two together but the basic idea would be to have:

OFF - no effect

Held - effect climbing/building up (more effect being added or more volume of the effect - not sure which yet)

Pedal Released (ON) - Full effect


The held state would be the equivalent of manually turning the effect knob up


EDIT:

Just had another idea for a use for it. I would maybe make a standard distortion using one of the schematics from here but put a filter on the held down stage and have a lo-fi/radio-y kind of distortion which would be kind of cool

[iaresee]

I think your best bet is to do this with a momentary switch and some digital logic. You can use digital logic to do analog hardwire bypassing. Check out:

http://www.geocities.com/thetonegod/switches/switches.html

You'd want to use a circuit like that, plus add a path that feeds a momentary on signal from your foot switch to whatever part of your effect would respond to a "held" signal. Maybe add an artificial delay on this path with a delay buffer so you have to hold it for a second or two to get a held signal fed to your circuit. I'll see if I can modify Andrew's last schematic there tonight for you to show you what I mean in a picture. But literally just add a tap off one of the inputs to that first NAND that comes after the switch and run it to a delay (right now all I can think of is maybe 4 inverters in a row just to delay it a bit...I'm hunting around to see if there's a CMOS signal delay in an IC that's easy to use...otherwise I'll draw something up for you properly tonight) and use that as your "ramp up" signal to control something.

The only problem with this approach is you couldn't hold the switch down to ramp up *and* keep the effect turned on. Every time you touch the switch the state of the effect would change. I'd need to think a little harder to tell you how to do ramp up but not change the state of the effect like the warp mode on the DD-6 or DD-20. Of course, if you went all digital like the DD-6/20 it's easier to do because you're using digital logic to determine what the user is doing with the switch, not trying to marry digital switching to an analog circuit.

[ollie]

i see, cheers for the link. I can just about handle that but was hoping it would be easier hehe - hoping the switch would do most of the work for me

Is digital logic the only way though? I thought there might be some kind of switch that has an intermediate stage (which is why i thought SPTT) that acts kind of like this:

[iaresee]

I'm not so knowledgeable on mechanical switches. Is a SPTT something that's readily available in stomp switch form? You've got me there.

You'll have similar problem with this layout as the one I described above: you can do a ramp up when transitioning from effect off -> effect on, but you can't do a ramp up once the effect is on and keep the effect on. That may not be a limitation you care about. Just pointing it out, that's all.

Why don't you just separate it into two switches? A bypass 3PDT and a momentary switch that does the ramp up function?

[ollie]

Hmm, been thinking about this and decided to try and do it differently

Is there anyway I can have a digital ramp controlling the amount of output? The only way I can think of is too have a stupid amount of comparators