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Wiring a relay to LCD

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  • Wiring a relay to LCD

    Hey everyone,

    I'm getting tired of seeing the blue NO INPUT SIGNAL screen on my Lilliput EBY-701 every time my car PC starts up. I would like to wire a relay so that I could cause a delay with the LCD powering up. My Lilliput is powered through an M2-ATX.

    This is what I came up with based on what I researched online:

    Could someone please double check my wiring diagram?

    Attached Files

  • #2
    Your wiring appears to be correct.

    But i don't think it will effectively achieve what you want.
    The anti-thump feature may turn on too quickly.
    give it a try though...

    you can try this
    which is a configurable timing device . from 0-60secs

    I did a quick search, and other members of this forum have used it.

    2006 Mazda6 Carpc

    2008 Acura TSX Nexus 7


    • #3
      ^ there is also the DEI 528T pulse timer that does the same thing-- just in a more "professional" wrapper.
      My OLD 2001 Mitsubishi Eclipse GT:
      "The Project That Never Ended, until it did"

      next project? subaru brz
      carpc undecided


      • #4
        And a triviality:
        Convention is that 85 is the more -ve compared to 86 (hence GND to 85, on/off signal to 86).

        This has no impact EXCEPT when relays with internal (spike quenching) diodes are used.
        And when people assume you have it wired conventionally.

        Personally I hate inbuilt spike suppression - I'll add my own (diode, not a crappy resistor!).
        Hence I like the un-conventional wiring that blows the crud out of internal diodes (so then I can add my own).

        Trivial indeed.
        I wire mine for the best layout. Black is my GND, else obviously a body connected wire.


        • #5
          @trinybwoy, thanks for the response. I may have miscalculated, but I timed it so that the amp turns on at the same time the bios screen comes up. I'd rather not spend $25+ on the device you suggested. I'll test this with a basic relay and let you know if it worked out.

          @soundman98, I actually came across that relay while reading PhilG's Worklog thread. If the standard relay doesn't work, I'll check it out.

          @OldSpark, I just learned about how relays work today (I knew what they are, I never have personally used them). I based my diagram off of a relay diagram I came across while researching the parrot bluetooth kits. I've updated the diagram to include a diode. Is this correct?

          Thanks for your help everyone!
          Attached Files


          • #6
            I doubt using a standard relay is going to give you enough delay. How long do you need? You can try this time delay relay, which delays for 10 sec. and in standard relay size package.

            Last edited by sall; 10-06-2011, 11:33 PM.


            • #7
              Originally posted by chaoszero View Post
              @OldSpark, .... Is this correct?
              Oh poo, now I feel guilty.

              All that was needed was to swap the 85 & 86 labels on your original relay diagram. (And then pretend you were looking at it from the opposite direction if that matters. I essentially never draw those "physical" representations. Instead I use circuit symbols (switch & coil) so that its circuit is easy to understand (not mentioning my avoidance of an inverter control thread) and the user can decide what type of relays they use. I don't use those Hella/Bosch DIN 85,86,30,87 relays.)

              But provided you understand that your new diagram has 85 to GND and 86 to the delayed M2 signal and you have merely added a spike-suppressing diode (to protect the M2), then yes, it is correct.

              FYI - I never worry about spike suppression - UNLESS the relay is being energised from an electronic circuit that is or may be sensitive. (Outputs intended for relays should be spike hardened, except for that stupid recent <whatever> product that required YOU to fit the diode! (Bad design, or brilliant (accountant's) marketing?)

              And the relay does not determine the delay - the M2 does that....

              PS - thanks sal for that 10s delay relay. Now UIBI users can have a "priority charging" system like those "voltage sensing" battery isolators! (LOL!)
              Last edited by OldSpark; 10-06-2011, 11:47 PM. Reason: ps...


              • #8
                @OldSpark, please don't feel guilty! I appreciate all the help I can get! I'm always glad to learn something new.

                I just threw this together in MS Paint, so it's no big deal. But yeah, I do understand what I drew. I just wanted to make sure it was right so that I don't end up shorting out/burning anything.



                • #9
                  MS Paint?? How pathetic - that's what I use!

                  FYI - For diodes, just remember their -->|-- symbol where the "arrow->" shows the direction current can travel, and the line-| is as marked on real diode's body. IE - current flows OUT the line end of the diode.
                  [ That's "conventional current flow" - ie, from +ve to -ve THRU the circuit.
                  Forget about electronic flow - electricity is not about the flow of electrons. ]

                  For spike suppression across a coil, it can't be "line to GND" because that would be a short from +ve to -ve (86 to 85), ergo it must be the other way. (Yes, it shorts the reactive -ve pulse when the coil is de-energised.)