using a button to switch multiple wires?

Discussion in 'General Electronics Chat' started by rafael adamy, May 24, 2015.

  1. rafael adamy

    Thread Starter New Member

    May 24, 2015
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    hi, I crafted a simple A/B box (wich I use to choose between 2 audio paths) that has one Microphone input and 2 outputs (all 3-pin xlr plugs) but for that, I had to use a 9-connector 2 way switch.

    I wanted to make a remote footswitch for that, so I'd have only one cable connecting the box to the footswitch, and I'd have one of those buttons that you step in to activate, but I don't know how to do that, given that those buttons are usually simple switches with 2 connectors, and also I don't recall seeing cables with 9 wires.

    how does that even work to switch 3 ways using only a simple button?

    thanks in advance
     
  2. rafael adamy

    Thread Starter New Member

    May 24, 2015
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    edit: no need to mention I'm a newbie to eletronics. I mean, I have made a few things by myself over the years, but never learned properly from books or so to know the names and technical specs of stuff
     
  3. ScottWang

    Moderator

    Aug 23, 2012
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  4. rafael adamy

    Thread Starter New Member

    May 24, 2015
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    alright, maybe this will help: (I looked up some names to make myself a little clearer)
    [​IMG]
    in black is what i currently have: a mechanical switch (TPDT?) to switch between A and B outputs.

    and in blue is what i want: a momentary spst switch to do the output switching. reason I want a momentary spst is 1. because it won't make a pop sound on speakers when pressed, 2. because I could hook up a relatively long 2-wire cable and control it from distance, and 3. I'd be able to press it with my foot.

    right now I have three different 3-wire cables in front of me, and I need to bend over and switch outputs manually, witch is far from ideal and is also causing noise on the speakers everytime I turn the switch.

    I don't know if that's achievable, I mean, it must be, but I'm not sure how complicated that could get, so using a SPDT switch could be an option also, if that makes it much easier. would still cause noise, but better than nothing.

    later on I intend to add 2 leds to the foot switch, indicating wich output is active, but first I want to figure this out.

    thanks again
     
  5. ScottWang

    Moderator

    Aug 23, 2012
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    If you using two dpdt switches and two long wires to do the remote control, then it could be works, but you need to care about the wires will watch the noise, if you using one spst switch to control then you will need to add some ee components as transistors and relays or as what I shown that it was used the cmos switch CD4066.

    If you just using two wires to control the switches, maybe you could do as this way:
    Two wires spst switch → debounce circuit + MC14584 → ck, ee toggle switch CD4013, Q → c,CD4066 I/O → Microphone In/out and choose OutA/OutB.

    When you completed the circuit, if the function is fine, in the beginning that the circuit will be choose OutA as default, you just press the spst push button once then it will be choose to OutB, if you press the switch again then the circuit will be change to control another ee switch and it will be choose the OutA.
     
  6. Sonoran Desert Tortoise

    Member

    Oct 30, 2014
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    A relay with 3 poles is an easy solution. If your application can tolerate 5 mSec switching times. The remote switch simply activates the coil (5 volts) and the three switches get thrown.

    https://www.digikey.com/product-detail/en/7143-12-1010/7143-12-1010-ND/710341


    Here is the manufacturers rather unclear schematic.

    image.jpg
     
  7. rafael adamy

    Thread Starter New Member

    May 24, 2015
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    Interesting, thanks for your replies!

    here was I, thinking I'd need logic chips and stuff, but a relay should probably do the trick!

    But I wanted to use a momentary switch for the noise, instead of a regular on/off, won't the relay only be active when I'm pressing the switch? Will it even make any difference using a momentary switch here since it's just for activating the relay?

    And since a relay is basically still a mechanical switch, just operated by magnets through electricity instead of your hands, wouldn't itself cause a pop on the connected speaker when switched?
     
  8. Sonoran Desert Tortoise

    Member

    Oct 30, 2014
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    Popping could be an issue with a relay or switch. I wasn't sure of all of your requirements. I am not sure how much pop you will get, maybe not much if switching short cables.

    You can get away without switching your ground pin on the xlr (should be common to both xlr cables) like below. You can do this with a dpdt relay.

    As for push button, you will need a stop-box like foot switch (press on, press off). You will need a 4-cell battery pack to power the coil (or a 5v cell phone charger).


    Regards

    [​IMG]
     
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  9. ScottWang

    Moderator

    Aug 23, 2012
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    The relay contacts have N.O(Normal Open), COM, N.C(Normal Close), when you are not press the switch then the COM and N.C will be connected together and the N.O will be open, when you press the switch then the N.C will be open and the N.O and COM will be connected together.

    When you using momentary switch then it can be switching the power on/off for the relays, and the relays can be control the in/out for microphone.

    Using ic is better than the relays and just used the switch, when you press the switch then the contacts of switch will be have the bounce happening, so sometimes we need to use the debounce circuit.
     
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  10. rafael adamy

    Thread Starter New Member

    May 24, 2015
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    Thanks! That's actually really helpful, I'll try connecting the ground wires together and see the results asap.

    I would use batteries since its more practical, but can't risk running out of batteries in the middle of a concert. Also don't know how long they would last, and having to keep replacing/recharing batteries wouldn't be ideal.

    I have a 12v, 400ma power source that I use on another effect pedal, and I was thinking of using an adapter with 2 plugs so I could use the same source for both the effect pedal and my AB box, and then I wouldn't need to connect 2 different sources into 2 power outlets. How complicated it is to make the relay work with a 12v power source? Would I need transformers of some sort or it's simpler than that? Aren't there different relays with different power requirements?

    Regards

    Yes, but I have never used any kind of integrated circuits, not sure where to start from. I'll try what Sonoran said and connect the ground wires together and use with the dpdt relay, and see if I still get any popping. I think that won't happen, but if does then I better start with IC.

    Thanks!
     
  11. Sonoran Desert Tortoise

    Member

    Oct 30, 2014
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    The exact same relay is available with a 12V coil voltage.
     
  12. rafael adamy

    Thread Starter New Member

    May 24, 2015
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    That's great news, thanks.

    Btw, I just tested my actual circuit but with the ground wires connected, and it didn't do anything to help the popping, sadly.

    I'll still get a relay and assemble everything, but any other ideas?
     
  13. Sonoran Desert Tortoise

    Member

    Oct 30, 2014
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    Seems like this would be an easier answer and the reviewers didn't say anything about popping so I assume they have it figured out.

    Assuming that you don't already have the connectors, the price of a DIY isn't so much better. I don't know if you like the switch but it is something fairly easy and no worries about batteries running out.

    http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=1D9G8194ADENN8NEXBPR
     
  14. irobot

    New Member

    May 16, 2015
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    Are you running +48V phantom power on these mics? If so, relays will not work any different than a conventional switch . . . nor do I think CMOS switches either . . . you will need a different solution.

    Hmmm . . . although . . . . phantom power or not - if you had a way to momentarily mute the preamp that your mics are feeding during the time you switch the mics . . . . that would be a solution to the pop/noise . . . .

    -Mike
     
    Last edited: May 25, 2015
  15. rafael adamy

    Thread Starter New Member

    May 24, 2015
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    The thing is, you see that switch? I need one that would be located away from the AB box. Also must be a switch that you can activate with your foot. Having a cable coming in and 2 going out is too much for the singer to have standing in front of him on stage, and having to operate it with his hands isn't great.

    And yes, I've already bought connectors and made one that looks almost like this one you linked, except mine pops when you flip the switch.

    It's a dynamic mic, no phantom power. Yes indeed that would be a solution but I'd have to either go to the mixer and press the mute switch, or modify my mixer's circuit, and those aren't reliable solutions.

    Maybe a momentary normally closed switch on the hot wires of the xlr outputs would mute them? Although I'd then have to hold this switch while I activate the other, and thats not good either.
     
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