2 Effects on box. 2 Foot switches to toggle between either or bypass

[taniwhatuu]

Hi people, Im learning so please bare with me.
I have 2 stomps im placing into one box.

The box will have 2 foot switches (one to activate/disengage each stomp).

I've worked out the simple approach which is basically combine the 2 inputs and outputs depending on the state of the particular fx footswitch.

But I would like to take it a step further by making one stomp control the active state of the other

Stomp A = 1 -> Stomp B = 0
Stomp B = 1 -> Stomp A = 0

Push stomp B and that disengages A
Push stomp B to disengage or A and that switches out the signal to bypass

Hopefully this pseudo code can explain what im trying to achieve?

if( FOOTSWITCH_A == PRESSED)
 if(A == 1){
   BYPASS ALL = 1
   A = B = 0
 }
 else if (A == 0){
   A = 1
   B = 0
 }
 else {
   A = 0
   B = 0
 }
}
AND same for footswitch B

kind of thing

[nick d]

            Sounds like you need something like an A/B/Bypass arrangement , like the one on BYOC .
              ( BuildYourOwnClone ) - I have built two of these , one as shown in the BYOC project , and
              the other in a box with two  fuzzes . Stomp 1 switches Bypass on/off , stomp 2 for Fuzz A/Fuzz B .
             

[samhay]

I don't quite follow your pseudo code. Do you want to be able to have both A and B on at the same time? If so, then I think you will need to use logic (and all the fun that entails). If not then, as nick_d said, you want a master bypass switch and an A/B switch.

[taniwhatuu]

thanks for the suggestion.

Yeah true it is a AB type thing with 2 buttons controlling each other
I'm trying to make it practical so I can stomp on the effect I want by selecting that pedal which will automatically deselects to other but also if I stomp on the same pedal again to deselect, it turns of both effectively bypassing and turning off both?

[taniwhatuu]

Only one pedal at a time, sorry the post just arrived after I sent the last one

[taniwhatuu]

I just came across this link http://www.geofex.com/Article_Folders/fxswitchr/fxswitchr.htm

Although I havent delved into CMOS Logic, I'm pretty sure I will LOL
The section explaining how to use CMOS logic describes how to route signals to various paths. Would this kind of thing be what I'm looking for based on my design model?

[samhay]

Right, so is this correct?

Stomp on A.
If A and B are off, turn on A.
If B is on, A must be off, turn on A, turn off B.
If A is on, B must be off, turn off A; i.e. bypass.

Vice versa if you stomp on B.

If so, then some form of logic is going to be needed. R.G.'s CMOS stuff is one way, but if you have some experience writing code, and don't mind springing for a programmer, then I would use a microcontroller (e.g. a PIC).

[taniwhatuu]

Thank you for the great input.

I don't mind learning a new language if necessary so PIC programming looks like a very useful option. Can you point me in the direction towards learning PIC?

I think I would work best learning to do what I want done in this design as a start I tend to work best in the deep end of things if you know what I mean.

[Quackzed]

would it be easier to just have switch 1 switch between circuit a or b
and have switch 2 bypass or engage the selected effect?
to switch from a to b or b to a stomp sw1
to switch from a to off or b to off stomp sw2
? am i missing some options, or is it always a or b or bypass and never both at once?

[taniwhatuu]

would it be easier to just have switch 1 switch between circuit a or b

Schematically I guess so. But practically I cant see.

You see. When performing I like to stomp on the box I am using not toggle between the two circuits with one switch. e.g

If I was to do that then;
If A is engaged and I want B hit the toggle (This is OK)
If its in bypass and B is engaged but I want A then I would have to stomp to A first then lift the bypass. Thats a small tap dance but none the less a tap dance it is. (NOT OK)

Or Am I reading the A/B/Bypass arrangement circuit wrong? If all it would take is pushing one button to get anywhere then yeah I could use it. But I dont see how that design would do that?

[samhay]

If you use logic (CMOS, PIC, discrete flip-flop, whatever) then you need something to act as a switch. Relays work reasonably well here, but the size of the circuit, and the expense increase somewhat.
Between the general forum and the digital sub-forum, you should find most of this covered in detail - http://www.diystompboxes.com/smfforum/index.php?board=19.0
In general, you want to look for 'electronic switching'.
If you want to get started with PICs, the gooligum tutorials are a good start - http://www.gooligum.com.au/

On a more pragmatic note, it's a good idea, at least intellectually and have been playing with something similar - using foot switches to do multiple things with taps, double-taps and long holds - but you may find that practically you are better off using a couple of independent 3PDT switches.

[slacker]

Or Am I reading the A/B/Bypass arrangement circuit wrong? If all it would take is pushing one button to get anywhere then yeah I could use it. But I dont see how that design would do that?

You're reading it right, to go from A bypassed to B engaged would mean pushing B and pushing bypass. If you put the two stomp switches close enough together you could stomp them both at once, removing the tap dance. Not quite as intuitive as simply being able to stomp A or B though.

[pinkjimiphoton]

seems to me you are way overcomplicating it. just wire two standard footswitches in the standard way you use, and make sure the output of one switch feeds the input of the other. easy breezy. can use either effect or bypass or both at will, with as little as one stomp. old style pushbuttons where you pushed one actuator and it released another were mechanical and really kinda overkill ffor this kinda project imho

[Mark Hammer]

Hi people, Im learning so please bare with me.

I generally only get naked with people I know really well, so you'll fogive me if I don't "bare with you" until you have at least 1000 posts here. 

Jimi is right.  We're making this too complicated.  A normal DPDT switch takes two contacts, and send them either over here, or over there.  For true bypass, we simply make the "here" contacts connected with a piece of wire, so that in and out are directly connected, and "there" is the input and output connections of the circuit.

In your case, though, "there" is actually one of two different choices.  So, we send the wires from "there" to the choice points on the 2nd switch.  And that 2nd switch now selects between sending the input/output contacts to the one circuit, OR to the other one.

[taniwhatuu]

Thank you for the input,

The reason for the overkill is that I want to utilize the idea across a few different switching projects. I've done a simple sketch up of the idea Jimi suggested which is fine cost wise and for simplicity's sake.

Please don't take this the wrong way but its not what I want my design to do, hence the reason for asking about the OTT option instead. If I was to build the suggested option I know I would never use it, give up and buy one or pay someone to do it for me instead.

I've got a fair bit of reading to do and thank you all for the suggestions

[samhay]

Sometimes we choose to do things because they are hard right?
You can do this with an 8 pin PIC and a transistor switching each of two relays. If you go down this route and you need a hand, I'm happy to help.

[slacker]

The cool thing about going down that route is that once you've built it you can reconfigure the switching at will, so you can have radio button style, A/B + master, A and B as separate things or whatever other combinations you can think of.

[samhay]

yeah - I was thinking the same.

[taniwhatuu]

Hi all, just an update,

Thank you for suggesting PIC.

I've been studying the code and ended up doing it with flowcode. asm code is awesome. .. very native. I decided in a PIC to analogue switch combination rather than relays for two reasons cost and compactness.

I've only tested it virtually so far using Designspark and LTSpice for the circuits and flowcode for the program simulation.

How reliable are analogue switches compared to relays?

Oh and also I know this was a bit OTT for a simple stompbox switch but it definitely makes my system more practical.

Because I've been learning PIC code i've also whipped up a few other designs of my own.

• A MIDI PC# to CC# converter for my whammy pedal so I can switch its banks via CC#
• A MIDI switching matrix controller for my amps channel, eq and reverb.

I can't see this being a sellable product as its now become apparent that there must be some kinds of restrictions designing and distributing clock based circuits? I'm thinking possible mobile interference? I dont know.

Im not doing this for money anyway.

But thanks anyway for the fantastic start.

[taniwhatuu]

Hey all many years later sorry!

In the end, I found it easier to use an arduino mini and multi opto relay shield.
I managed to get the options I wanted but fitting into the enclosure was pretty tight.
I've been using this for years now and it's run well with no issues. On the cost side of things though, it cost me more so definitely not a sale item but something I wanted for my own needs 

Thank you all for your input and ultimately helping me decide what worked for my needs
Keni