DPDT momentary/off/on wiring question

Discussion in 'General Electronics Chat' started by DHB, May 16, 2012.

  1. DHB

    Thread Starter New Member

    May 16, 2012
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    0
    I know almost nothing about wiring and electronics, so bear with me.

    I have a set of 3-wire, flashing LED lights that I need to wire up. They work in such a way that red is power and black is ground. The third wire, yellow, will change the flash pattern of the LEDs when connected to the power source for a moment. For this to work the unit must already be "on" (i.e. the red wire is already connected to power)

    So here's what I'm thinking: get a DPDT switch with momentary on/ off/ constant on. Then, wire it in such a way that the unit will be "off" when the switch is in the "down" position, will be "on" when in the center position, and will change the flash pattern when flipped to the momentary "up" position.

    Attached is how I *think* the switch needs to be wired for this to work, but I really have no idea. Am I far off the mark here?

    Also, with the DPDT, will there be a brief break in current when I go from "on" to "momentary," such that it will turn the unit off and thus negate the ability of the unit to stay "on" as I try to switch phases?

    [​IMG]
     
  2. BSomer

    Member

    Dec 28, 2011
    433
    106
    It would probably be best to use two separate switches. One SPST switch to apply power to the circuit and the second as a momentary normally open. I had bought a couple of switches from somewhere once that were two rocker type switches in one package. One was a SPDT and the other was a momentary, I think I got them from the All Electronics website.
     
  3. DHB

    Thread Starter New Member

    May 16, 2012
    4
    0
    I've thought about that, but I'd like to keep it contained to one switch if at all possible. And I think I see a problem with my diagram. The way I have it set now, the current will flow from the center right terminal into the lower right terminal whenever the switch is in the center. This is no good.

    What if I just bridged the lower left and center right? would that solve the problem?

    [​IMG]
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,638
    2,344
    Hello,

    Do you have more details about the used switch?
    A datasheet would be perfect.

    Bertus
     
  5. DHB

    Thread Starter New Member

    May 16, 2012
    4
    0
  6. bertus

    Administrator

    Apr 5, 2008
    15,638
    2,344
    Hello,

    With the switch it is only possible to have a constant connection to one side OR a momentary connection to the other side.

    Bertus
     
  7. DHB

    Thread Starter New Member

    May 16, 2012
    4
    0
    The more I look at it, it seems like you're right BSomer. This is a two-switch project.
     
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