Relay foot switch

Discussion in 'The Projects Forum' started by JodyP, Jul 18, 2016.

  1. JodyP

    Thread Starter New Member

    Jul 18, 2016
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    I'm a lapsteel guitar player I have a Leslie cabinet project in mind, well it's really more of a foot switch controller I have in mind. I'm not electronics guru, so hopefully you guys won't make too much fun of me for not knowing the lingo or the how too. In case your not familiar with what a leslie cabinet is here is a quick video someone posted on youtube.
    I'm am currently operating the leslie with a 110v foot switch, a lamp on/off switch, that turns the small 110v motor on and off. Having 110v under my feet in a cheaply made foot switch that I'm stomping on and off 300 times a night just doesn't seem safe. After doing some searches and watching some videos, I think a foot switch relay circuit is what I need to create. I have an old guitar tuner pedal with a latching on/off switch, its ran off 9vdc, and I'd like to use it as the foot pedal. Using the foot pedal I'd like it to send 9vdc to the coil of the relay, which I'd have mounted in the leslie cabinet, to supply 110 volt to the motor. I don't see a lot of 9vdc relays online, but I think this one would work? This sounds easy to me now that I've typed it all up, but I lack experience and confidence and hoped someone with skill can confirm this is all I need for a solution to my problem?
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    That relay should work it is intended for printed circuit however so you would either have to mount it/glue it to a surface and hard wire the pins or some other method.
    The other method is to use something called strip perf board where you can solder terminals strips and relays etc, but the former may be easier if you are not into electronics.
    BTW, when using that relay break the small tip off the one corner after fitting, this is a vent that is used to seal the relay when a relay is board mounted and coated when the coating is dry the vent is opened.
    Max.
     
  3. JodyP

    Thread Starter New Member

    Jul 18, 2016
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    Thank you very much for the input. I'd rather have a relay that comes with tabs to mount it. I see several 12vdc coil relays and I've read where some say a 9v batter is enough to engage a 12 volt one? What do you know about that?
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    As a rule this is true, relays have something called hysteresis which is the difference in voltage that it will pick up at to where it drops out, once energized, it takes less energy for a DC relay to stay picked up than that of the rated voltage.
    Is it a battery for the source of the 9vdc?
    If so this will decrease as it loses charge.
    You can also get some relays known as ice cube and have a plug in socket that has terminals.
    There are also automotive relays from wreckers etc.
    Max.
     
  5. JodyP

    Thread Starter New Member

    Jul 18, 2016
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    Thanks again. Yes, I'd be using a 9v battery most of the time, but the foot pedel is also setup for a 9v power supply. I rarely use the power supply, but would if it drained my the 9v battery to quickly.
     
  6. MaxHeadRoom

    Expert

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    Small power supplies are cheap such as wall-wart type, this way you could run it off of 12vdc.
    You have a 120vac source evidentally.
    Max.
     
  7. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Relay coils can be quite current-hungry, so a little 9V battery wouldn't last long. A solid state relay (SSR) might be worth considering if its control input uses less current. It would also be silent in operation (but I doubt that's a concern when you're banging out 100db :) ).
     
  8. JodyP

    Thread Starter New Member

    Jul 18, 2016
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    Thanks Alec and Max.. Wouldn't THIS solid state relay work? They come with or without the heat sink, do these generate that much heat with 110v? I'd rather use a 9v battery in the foot pedal since I'd like to reduce the amount of wires at my feet as much as possible. I'd be happy with 48 hours of battery life if I could get that.
     
  9. MaxHeadRoom

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    I don't see the power rating of the motor? 25amps may be a little overkill if just a small motor, does it state the current on the plate?
    Max.
     
  10. JodyP

    Thread Starter New Member

    Jul 18, 2016
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    So now I'm about to show my complete lack of electrical knowledge...... I thought a SSR is set to handle up to 25 amps it would work just fine even if the motor only draws a half an amp, but maybe I just dont know enough about relays. I would have thought that in the end the motor just needs that 110v. My reason for thinking that way is this; I have a 100amp breaker feeding my man cave. It goes to my breaker box which has 4 20amp breakers. At times I only have a single 100 watt light bulb on that 20 amp circuit and it's not 'overkill' for that 100watt light bulb..
    Do I sound like an idiot?
     
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The 25amp SSR will operate a small motor OK, it is just you do not necessarily need that capacity for a fractional HP motor.
    Max.
     
  12. JodyP

    Thread Starter New Member

    Jul 18, 2016
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    Gotcha.. I thought you were saying it would burn it up..
     
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