Momentary switch with TRS jack

[Sophia2001]

Dear fellow builders,

I'm working on a pedal for a good friend. She has the following wish: switch the effect on/off with a TRS output (momentary). When the momentary switch is pressed (Carlton switch 1 pole OFF-(ON) SLDR) the effect should come on. When the switch is off, the original sound (dry) should be audible.

Does anyone have an idea how I can accomplish this?

Sofia 

[Mark Hammer]

It's not immediately clear what the "TRS output" is for.  Are you trying to provide momentary switching of a stereo pedal?

[GibsonGM]

Or do you perhaps want to replace the bypass switch using a TRS jack, to a remote switch?

[Kevin Mitchell]

Momentary = non latching connection
TRS = tip, ring, sleeve (AKA stereo jack/cable)
Your question is crossing two things that don't go together.

By the sound of it, your friend either wants a remote bypass/effects option or a simple no-click switch mod.
I can't make tails of which one you're asking for 

[Matthew Sanford]

Paring the info down, TRS jack doesn't seem to matter. If you're building it and have room for a momentary, you might connect it in series between the input and a pull down resistor so when it isn't connected the circuit input has a ground connection to help keep noise out. If it's in the middle of a chain of effects and the want to remove it, a DPDT momentary (normally off) set as a bypass may be the way.

I could be wrong of course

[Sophia2001]

Thanks for all the responses. Sorry for my unclear explanation. I will try to explain it more.

The schematic consists of a JMK Panner that works as a blend.



The schematic is switched on with a True Bypass 3PDT switch. She would also like to have the option to have a "momentary" option in addition to the "always on" option. The housing has a TRS output jack. Could I adjust the schematic so that she can switch on the schematic with that TRS output jack momentary (by using an external switch).

So TRS switched on (tip/ring connected) is effect on.
So TRS switched off (tip/ring interrupted) is effect off.

Reason: she has a switch on her pedalboard with an BIG knob   This is easier to operate than the small 3PDT switch.

Hopefully my question is clearer now? Thanks!

Sophia 

[bluelagoon]

You need to define what the Big Knob Switch type actually is. Is it a momentary normally open type or normally closed type. Is it in fact a momentary switch.?
Also there appears to be 4 jacks already in the circuit,
1/ Input
2/ Output
3/ Send
4/ Return
Do you intend to make it a 5 jack box with the addition of an extra Stereo Jack with Tip/Ring/Sleeve to facilitate your Bypass switch intentions?




Now you just need to figure how to get your momentary Bypass working

[bluelagoon]

Perhaps the following might suffice, Although I feel you would still get the blended effect coming through along with the original signal bypassed, which wouldn't be a true bypass, and not the desired outcome.
If you could incorporate a DPDT Relay into the mix that was activated from the Momentary N/O, then you could likely achieve the right outcome.

[Sophia2001]

Thanks both for your help!

You need to define what the Big Knob Switch type actually is. Is it a momentary normally open type or normally closed type. Is it in fact a momentary switch.?

Normally open, like this:

Do you intend to make it a 5 jack box with the addition of an extra Stereo Jack with Tip/Ring/Sleeve to facilitate your Bypass switch intentions?

Correct.

Now you just need to figure how to get your momentary Bypass working

That's my question! 

[RickL]

Back in 2006 I posted something that may help you out. https://www.diystompboxes.com/smfforum/index.php?topic=48813.msg362251#msg362251

It won't allow you to use a momentary switch to control your box, but it does let you bring in the effect momentarily with a dpdt momentary switch, and also take it out momentarily with the same switch.

[bluelagoon]

Hey Sophia, If your still about and interested in a solution to your switching dilemma, I finally got to finish putting together a schematic for you.

Here it is, a working unit of what you wanted to achieve. All it really takes if you are up for it is to get rid of the 3PDT Foot switch, purchase a few extra reasonably cheap components for the new type Micro Controlled Relay Switching Scheme added to the original Panner FX circuit.

The main component needed is the Pre Programmed VFE PIC12F509 Micro Controller. I believe they may still be available for purchase at MadBeans Pedals on the internet. Or if you were in Australia I could easy send one your way.

There's not a lot of extra reworking to be done, you might easily fit the micro controller relay switching circuit onto a smaller separate prototype pcb board. and wire it up adjoining the Panner effect PCB accordingly.

Then you get the external momentary extra jack fitted that will allow for momentary depression on that external switch to deactivate the FX and go to Bypass mode for duration of the switch pressed down.







My main aim was just to provide a suitable solution to the switching dilemma faced by Sophia in the OP.
I think this slight mod to the VFE switching scheme fits the bill okay.
Just wondering if the R12 1M pulldown on the output is possibly a bit of excess overkill ?
The Zener diode could likely be omitted as both the regulator and the op amp are both capable to 30V DC
Please chime in all you knowledgeable folk if you see where something could better be suited to the overall circuit.

Hope this might help Sophia, Although it could be a bit of a challenge.
Will leave it with you.

[jorg777]

You don't need a computer chip or programming skills for this job.   

Insert a CD4051 analog switch (Costs about $0.32USD) just before the output jack.  Connect one of its common terminals (the chip contains 3 SPDT switches) to the output jack.  Connect one input of the same switch to the "S" signal in your circuit, and the other CD4053 input to the signal which was formerly the output.  Wire your external control input with a pull-up, and make the external switch short that external input to ground.  Connect that control signal to the CD4053 control input.  If you've wired the "S" signal and the normal output signal to the right switch inputs, when the external switch is not plugged in, the CD4053 will allow the pedal to act normally.  If you plug in the switch and press it, it bypasses the effect.  Release the switch, and the effect acts normally.

If that's not the logic you want, you could play a trick with your TRS jack.  If you plug in a TS plug (no "Ring" contact; i.e. mono instead of stereo plug) it will short the tip and ring contacts together in your TRS.  That could connect a low-resistance pulldown which overcomes the pullup resistor.  Then, wire the tip contact to +9V.  This arrrangement lets the pedal "Act normal" when no external switch is plugged in.  Plug in the switch, and it bypasses the effect.  Step on the switch, and it engages the effect.

[bluelagoon]

Thanks for the heads up, but I cant follow too easy the dialogue, I follow schematics of these relative simple circuits much better.
There is always a better mousetrap. But I like the one I put up, it switches and works for what the design called for, tested and all.
So please draw me a picture, then we have something to compare.
And PS: I dont know much about multiplexors, but I am sure they like all the rest solutions likely come with their own set of problems and nuance inefficiencies. Tell me it isn't so, Go draw me picture.
You might be right, I could comprehend better where your coming from with a schem type diagram.
There is a good article over on RG's Geofex site about the multiplexors.

Geofex Multiplexor Switching

Never personally experimented with them. Sure they have a use and a place for using.
Cheers.

[merlinb]

.

[jorg777]

[jorg777]

[bluelagoon]

Thanks Jorg777 for the pic of circuit using the CD4053, looks interesting, might get one on to a breadboard and see what it does.
With the control where it states +9v = Normal and 0v = Bypass is this meant to be a toggle switch between those 2 voltages to alternate the momentary switch function to either bypass on when effect is in, and opposite of effect as momentary when in bypass ?
Just need some clarification,
If I get it onto the breadboard, am sure can figure a few things out how it works.
And I guess it would need an insulated Ground jack as the external switch input socket to avoid direct ground to the box.
Looks like quite an easy concept to achieve the end result, like you said, and so much easier understood in image form than the directions you gave earlier, for myself at least.
Cheers

[jorg777]

Yeah I should have just started out with an image.     You are correct about using an insulated socket for the control input!

What I intend the behavior to be:

With nothing plugged into the control socket, the effect is always engaged.
If you plug in the external switch, the effect only engages while you step on the external switch.  When you release the switch, the effect is bypassed.

[mark2]

Late to the party but here's an AVR microcontroller solution that'll provide an alternate way to achieve the same goal: https://github.com/mstratman/relay-bypass

You can hook up two momentary foot switches, one in the pedal, and one remote via a jack. They both operate the same: Tap to toggle between engaged and bypassed, or hold down one of the switches to momentarily toggle, then release to toggle back.

[FiveseveN]

I feel like the goal has been woefully misunderstood.

With nothing plugged into the control socket, the effect is always engaged.
If you plug in the external switch, the effect only engages while you step on the external switch. 

This can be achieved with a normalling or other kind of switching TS or a basic TRS jack. Absolutely no need for a uC.
The actual bypassing can be done with relays or CMOS MUXes as usual.