multi pedal switching

[numpty]

I've built a number of overdrive and distortion boards which i would like to house in one box, each one is to have its own footswitch. I would like to arrange it so that it only requires one depression of each switch to select an individual effect, similar to a push-switch channel selector on an old tube radio or like the buttons on a copycat. Are there any practical schematics available which achieve this electronically or by using relays or LEDs/LDRs etc?

[Seljer]

I've been thinking about this for a while, here is something that I think would work:

-momentary switches for each effect
-with SR flipflops for each effect, things are wired up so that pressing the switch sends the signal the the set input of one of them and to reset of all the others so only one of them is on at a time (there are various ways you can do this)
-your choice of switching system (relays, cmos switching, the Boss JFET thing....)

there are a bunch of articles on various switching systems of geofex if you go take a read

[R.G.]

Seljer is correct. There are articles at GEO which do exactly what you want. Try reading all of the articles on switching at GEO and see if your questions get answered.

[disto]

i had a quick look at some of the articles on GEO and they seemed good, however need to re-read through them it didnt sink in the first time!
i was considering building some kind of switch system to control external effects so i can have say 4 presents with a combination on pedals eg preset one is a distortion and phaser preset 2 just a wah etc

[RaceDriver205]

Disto, if you can wait about a month or so, this is what you can build for yourself:

The control features will included:

• UHF remote connection to multifx/pedal array system, with option of straight cable
• Two pedals (up/down) which select pre-programmed effects combinations
• Maximum of 64 (or 99) possible effect-codes with any combination allowed
• Keypad for programming in combinations
• Backlit LCD screen for displaying effect names/combinations
• LED display for current combination/effect number
• Computer Interfacing to allow management of available effects or effects combinations
• Rechargeable battery array with power indicators

(from this http://www.diystompboxes.com/smfforum/index.php?topic=44752.msg338094#msg338094 thread)
Might be a bit too much for your needs perhaps. 
Youll have the option of ommiting a lot of the stuff you don't need though.

[disto]

wow looks intersting didnt have time to read through it all but i will do! might be a bit more that i was looking for but it will be interesting was there a previous topic about it? that seems to be a progress report!

[numpty]

Hi
I read the article on the cd4053 and another called "wicked switching" using a 4066. I'm not clear on how I can a use them for my application. For example if i have four effects say each to be used separately how can i select each individual one if  each switch must switch on the 12v on supply for the "on switch" of 4066 (or 4053) and also simultaneously switch off the others?

[RaceDriver205]

Lol, no no disto, thats stuff im working on.

Numpty, the 4066 switches are switched by a separate "switch input".
For each of the internal SPST switches there are:

• Two pins that are the 'terminals of the switch'
• One pin that flicks the switch on if its input is +V and off if its input is GND

Not sure you were sure on that so I mensioned it anyway.

If you can tell me how many effects you want in the box, ill post a switching schematic to fit.

[numpty]

Hi Racedriver205

    Thanks for your help. I intend to up to 8 effects in this box although I only have four boards built at the moment. They will be all distortion / overdrive effects, so i will only be using one at a time,
but i want the facility to switch from one to another instantly without any fuss ie: with just one press of a button. if 8 proves too be to complex a task, 4 will work if i only incorporate my favourite effects.

[RaceDriver205]

8 will be fine. I hope you have access to SPDT or DPDT momentary (push button) switches.

[RaceDriver205]

This should do it:

Should work fin. If you could test it that would be great, there is a lot of people asking about switching devices, so my contibuting a new one would be usefull.

[numpty]

Yes I have access to various types, I will use the heavy duty version for reliability. look forward to seeing the schematic incorporating them along with the 4066

[numpty]

Hi Racedriver205
    thanks for posting the schematic, i will certainly try it out. For another bank of four do you repeat the switches and associated components add another cd4076 and use connection 7 of the LM555c ( discharge out?) or do you use 3

[RaceDriver205]

Hmm, good point. I was going to say just repeat the circuit twice on the same board, and connect the GND, +V and Com terminals together. But yes, on the second circuit you could omit the 555, and use the output (pin 3) from the first circuit.
For use with a 4066, you could add a 4069 inverter to the circuit, and run A,B,C,D in to it. This would give you the inverse of  A,B,C,D.

[KMS]

Without getting too complicated..........I built a matrix for my 6 Chanel router....for which I have found that in most cases I only use two channels and for most songs I only need to switch between two FX set ups for the entire song.  So I have 54 potential functions in my router for which I only use about 5% of it for any given song.   Darn all that wiring has gone to waist....It is cool though.

OK....do you get what I'm trying to tell you.....you probably don't need to much routing to do a gig.

With that in mind you can make a 6PDT momentary stompswitch for about $10 real easy.

Get two 4PDT "latching" 5VDC relays (1 amp contacts so the arcing doesn't weld the relay closed) Two diodes and one SPDT MOM and you have all you need to make the 6PDT Stomp.  Wire it so when you depress the MOM to the NC position one relay switches and one of the xPDT changes the route of the NO section of the MOM to engage the second relay.  When you return the MOM to NO position then the same wiring is applied to the other relay for the NC position at the same time the opposing relay is switched.

Most of these 4PDT relays are 5VDC and will need 9VDC to operate simultaneously in this set up.

It is a flip flop relay configuration that uses 2 of the 8 poles from the two 4PDT relays and you must have latching relays leaving you 6PDT free to operate your FX.  You must regulate the negative back lash of the coils..see..GEO FX pages to set up the diodes for the relays.

Once you have this type of stomp switch you can bypass one FX and LED at the same time you turn another FX and LED on.  You can then set up buss bars from each of the "throws"  with DPDT or SPDT toggle switches to select any two FX for a  two FX preset. Two toggles per FX.

This allows you to do everything with one stomp.....and all your presets are toggles....Sorry, I do not have a schematic ........it is not that hard to do....just start drawing it out on paper and it will come to life.

It takes a lot of shielded cable to do this bty.  Better get a 100ft just to get going....those little 1ft pieces add up real quick.

[RaceDriver205]

Ah, thanks KMS, but I think thats a bit too complicated for the job in hand. I fancy a digitally implementation shown in the schematic would cost less money and less hastle. Note that indicator LEDs could be wired direct via resistor to the A,B,C,D outputs.

[Transmogrifox]

numpty--if you're into learning microcontrollers, this application would be a really nice beginner programming application.  It looks like the Digital/DSP part of the forum is really taking off and you would be able to get quite a bit of help there.

It would allow you to break all that down to a single 14-pin chip that's internally clocked.  What's nice about that, is if you decide you want to change the function, then it's just a simple matter of programming another chip, pull the one out of the socket  and replace it with one that's programmed to do something different (or just reprogram the one you have).

The downside is that you have to learn how to do it.

[numpty]

Hi
  All thats way above my head ,but I think i will give racedrivers205 circuit a go. I understand that cmos chips can be easily damaged by static, so i might have to get one of those wristband gizmos

[Transmogrifox]

I haven't had too much trouble damaging my CMOS chips with static.  Hold the chip in one hand and use the other to touch the circuitboad or table/surface you are about to put the chip in/on. That way you discharge the static through your fingers instead of the chip.  Once you're discharged, the chip is safe.

Likewise, touch the surface that the chip is on before you pick up the chip.  The wrist band gizmo just keeps you discharged all the time (which is nice if you're doing a lot of CMOS handling).

The wristband gizmos are most suited to mass production applications where you have techs handling hundreds of chips and circuitboards a day.  It can be pretty expensive for a company to lose 10% of their cuircuitboards to ESD.

About microcontrollers: it wouldn't be way over your head if you started frequenting the Digital/DSP section.  You'd learn fast.  I only recommended it as an idea in the event you want the option of being able to change the circuit's function without having to build a completely new one.  There's nothing wrong in my mind with building racedriver's circuit since it's straightforward, and you can get it done with little or no addtional learning.

[RaceDriver205]

I for one will vouch for the usefullness of microcontrollers/processers. But they are a computer afterall, and they can certainly be an overkill. I think most people think "Oh use a PIC" whenever they need a digital circuit coz it requires the least thought, but like valves - discrete logic ICs will always have their place. Discrete logic can also be cheaper, esp. in this application.