LED strips with extra conductor?

Discussion in 'Electronics & Electrics' started by dufflover, Feb 19, 2020.

  1. dufflover

    dufflover Member

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    The most common application I use LED strips for is sensor lighting using a MOSFET to control it. If using it for say a staircase or hallway, I want trigger points on both ends of the strip. That requires an extra conductor to run along the length of the strip.
    Are there LED strips around, or some other convenient method, where basically there is an spare "wire'/track running along the length of strip? When I put in some lighting for my folks place, I resorted to using super glue to run a wire along the weather sealing. Did not look as bad as I'd thought, but just one of those things in my head where I think surely such a product exists with this application in mind so it's not necessary?

    I'm talking normal LED strips, not RGB controlled ones, although if their extra conductors can be somehow used to achieve this then I'm all ears.
     
  2. merlin13

    merlin13 Member

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    "...That requires an extra conductor to run along the length of the strip..." - Short Answer? Not that I've ever encountered. Would have to assume such a (readily?) available isn't that prevalent due to most LED strips are normally run off single-source low-voltage DC.

    AC mains-powered ones are available if you want to have a look at that perhaps. Honesty not looked at those in depth myself yet but pretty sure you'd be in the same pickle, and at Seriously Bitey voltage levels...:)

    You "could" dick about stripping the LEDS of a tri-colour strip and fiddling plain white ones onto it, but that's going to be a loooot of careful dicking about with the soldering iron.

    Depending on how your sensoring and access to power is set up, you might need to ponder running two strips - one controlled 'n powered from one end of the stairs, the other run form the other end...
     
  3. aXis

    aXis Member

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    Just thinking, some crazy outside the box stuff.

    1) Run the strip at some lower voltage that wont exceed the LED diode threshold. Often there will be several diodes in series so you might get away with 6 volts or so.
    2) Have the sensor on the remote end trigger a change in loop current that can be detected, eg standby current on the PIR might be 5mA, when motion is detected then sink an extra 10ma into a dummy resistor.
    3) At the supply end, detect the current change and then switch to higher voltage (that turns on the LED's) for some preset period of time.
     
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  4. ShadowBurger

    ShadowBurger Member

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    surely you could stick some ribbon cable to the back of the LED strip? Something like https://www.ebay.com.au/itm/303102468485 and obviously tear off the extra cores so it's not wider than the LED strip

    should be fairly nicely out of sight on the back of the strip
     
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  5. OP
    OP
    dufflover

    dufflover Member

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    Yeah, looks like I might have to resort to something like that. The only issue with the ribbon cable idea is I can't really prewire/solder everything without removing the adhesive backing tape off the strip if I need to attach (say) a narrow pair of wires down the middle; leaving a top/bottom track of adhesive still so it sticks to the surface.
     
  6. ShadowBurger

    ShadowBurger Member

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    When I did this in the in-laws patio I stuck the ribbon to the LED strip with the LED strip's own adhesive, then put new double sided tape on the back of the ribbon cable. I only needed the extra cores for power as it was an 11m strip
     
  7. OP
    OP
    dufflover

    dufflover Member

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    ah okie doke. Thanks for the tip. Never would've thought of that myself! d'oh

    So I could pick up a roll of something like this?
    https://m.aliexpress.com/item/33001065229.html
    (Haven't checked that's the cheapest/best, just for an example)
     
  8. wingnut

    wingnut Member

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    I have been considering a similar but for garden and path lights
    A consideration is a device at each end using uart or such to communicate
    Run the power in reverse bias in standby and then when triggered your master end feeding the power changes the polarity for a set time You protect the slave end detector with diodes, maybe incorporate some caps to prevent delay of the detector starting up again when timer ends and power polarity changes back to allow resumption
     
  9. RobRoySyd

    RobRoySyd Member

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    That should be fine.
    Alternatively might be possible to run a single stand of enamelled copper wire under the double sided tape that's already on the LED strip. It doesn't need to be a heavy gauge and the insulation should be more than adequate. Most importantly enamelled copper wire is so much thinner and hence less likely to disturbed the existing adhesive. I'm also kind of a tad nervous of the idea of running two levels of double sided adhesive tape as it really sticks to itself.
     
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  10. mtma

    mtma Member

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    And it really doesn't want to stick to what it doesn't want to :lol:

    Probably I'd either go double layer or slit the foam adhesive and embed a thin wire so the adhesive isn't fighting the extra conductor when attached.
     
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  11. aXis

    aXis Member

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    Thin enameled wire sounds like the go!
     

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