Combined Temporary/Toggle bypass?

[Gereze]

Hey forum,

Im interested in making a trem with 2 type switching. I'm not sure about the name of this so I don't know how to find it.

Basically I wan 2 switches, one latched and the other one not latched.
When the toggle is in its first position the effect is off and the temporary one turns on the effect.
When the toggle is in its second position the effect is on and the temporary one turns the effect off.

I see I could get it done with a non-latching 4PDT and a DPDT (3PDT for led). But I feel that I'm missing something here. DOes anyone knows or has an idea on what other way I could achieve this?

[R.G.]

It is complicated to do it with hard switches, not least because the "toggle-ness" of a switch is built into the mechanical part of the switch. If I were doing this, I would do it electronically.

First off, I would move the actual signal handling to a $3 PCB relay. That frees you from having to do the actual signal switching with your stompswitches.

Next, I'd use two momentary stomp switches. These only tell the "thinking" part of the circuit "do it now".

Next, I'd design one latching circuit (half of a CMOS IC does this easily) and one circuit that ether latches or is momentary depending on its hard switch input and the state of the other side. This second side runs the actual signal switching relay.

Sounds complicated, I know, but it's actually simpler to design and test than the switch logic you're contemplating.

Two or three $0.50 CMOS logic chips do it. Actually, I would use an 8-pin $0.75 microcontroller. I have done this before. In fact, I did it to read an eight-switch wide bypass switching rig.

One trick that is important in doing this is to recognize that a switch making contact and a switch breaking contact are two different events.

[idy]

Simpler would be making the pedal "non-true bypass." (Or another switch for true bypass....)
The two stomps (latching and non) just turn the LFO on and off. A lot of people liked the EA tremolo as a preamp... Two 3p and you get the LED with both stomps.

[Gereze]

It is complicated to do it with hard switches, not least because the "toggle-ness" of a switch is built into the mechanical part of the switch. If I were doing this, I would do it electronically.

First off, I would move the actual signal handling to a $3 PCB relay. That frees you from having to do the actual signal switching with your stompswitches.

Next, I'd use two momentary stomp switches. These only tell the "thinking" part of the circuit "do it now".

Next, I'd design one latching circuit (half of a CMOS IC does this easily) and one circuit that ether latches or is momentary depending on its hard switch input and the state of the other side. This second side runs the actual signal switching relay.

Sounds complicated, I know, but it's actually simpler to design and test than the switch logic you're contemplating.

Two or three $0.50 CMOS logic chips do it. Actually, I would use an 8-pin $0.75 microcontroller. I have done this before. In fact, I did it to read an eight-switch wide bypass switching rig.

One trick that is important in doing this is to recognize that a switch making contact and a switch breaking contact are two different events.

This sonds more like it. Will have to do some reading about it, thanks!

[MJ_Sound_Cubed]

Interesting, maybe the way to go would be 2 DPDT relay with an IC. 

[R.G.]

You can't just wire them in parallel - if they agree on the toggled/alternate action state, all is well, but in the condition where the momentary one is different from the alternate action relay, much hilarity - and typing on forum entry pages - ensues.

[RickL]

if you don't need indicator LEDs this will work:

http://www.diystompboxes.com/smfforum/index.php?topic=48813.msg362131#msg362131


or is this what you were referring to in the original post?

[Suicufnoc]

I'd do one footswitch, make short press toggle on or off, and long press momentary. Just have to experiment to see what time threshold to use

[ElectricDruid]

I'd do one footswitch, make short press toggle on or off, and long press momentary. Just have to experiment to see what time threshold to use

I've used half a second for the threshold for this job and that seems fine. A short "tap" is less, but a more deliberate "press" is longer. The Digidelay works like this, and I've not had any emails complaining about the threshold, so it seems to be ok for most people.

[GGBB]

if you don't need indicator LEDs this will work:

http://www.diystompboxes.com/smfforum/index.php?topic=48813.msg362131#msg362131

Here's a visual diagram of the switching circuit from that thread with LED added using a 4PDT bypass switch:

[matlevo12]

I'd do one footswitch, make short press toggle on or off, and long press momentary. Just have to experiment to see what time threshold to use

Hi

I'd like that !
Anyone could share an idea (or an actual schematic) on how to do that ?
I had no problem doing it with tho switches (one latching and one momentary), but I can't understand on how to do it with one and differentiate the long and short presses.
Thanks a lot !

[ElectricDruid]

I'd do one footswitch, make short press toggle on or off, and long press momentary. Just have to experiment to see what time threshold to use

Hi

I'd like that !
Anyone could share an idea (or an actual schematic) on how to do that ?
I had no problem doing it with tho switches (one latching and one momentary), but I can't understand on how to do it with one and differentiate the long and short presses.
Thanks a lot !

While there are ways to do it with analog circuitry, it's one of those cases where  a 0.50 microprocessor (AVR/PIC/other - take your pick) does the job much easier and cheaper. For the DigiDelay pedal I described above, it was an addition to existing firmware for the dsPIC porocessor I was already using. For other people her using a processor to control a noiseless true-bypass or similar system, this kind of thing can also be added to the software.

Tom

[matlevo12]

Thanks a lot for the tip !
I've searched quite a lot about something similar to Earthquaker Devices Flexi-Switch, but I'm kind of surprised that (to my knowledge) no one has already try to replicate it !

[matlevo12]

Hi !

I finally found a way to replicate a EQD flexi-switch.
I just used coda effect's relay bypass (https://www.coda-effects.com/p/relay-bypass-pcb.html WONDERFUL website really worth the visit !), which is using a PIC12 microcontroller and changed the code so that it does what the flexi switch does (short push = change, long push = momentary change while you're pushing).

If anyone reads this, do you think it's worth creating a topic just for that ?

Bye, thanks !