Help with a switch and some Leds

Discussion in 'General Electronics Chat' started by live4soccer7, Jun 16, 2008.

  1. live4soccer7

    Thread Starter Well-Known Member

    Jun 7, 2008
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    I am currently installing conversion from the normal bulb to LEDS in my dome light. There are three settings are there are in typical cars, on always, off always, and on when the door is open. I have pictures with these to help with the understanding. I have wired up 20 leds in several series and I am not sure how to wire them up to this particular setup. Any help would be greatly appreciated.

    Here is the first picture - always off

    [​IMG]

    Second Picture - On when door is open

    [​IMG]

    Third Picture - Always On

    [​IMG]

    Last Picture - The back of the switch (just thought i'd put it)

    [​IMG]

    The silver metal part in between the two bronze looking ones is the power and the bronze ones are the grounds.
     
  2. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
    The camera fuzzy logic is working correctly. That's fuzzy.

    Try setting the focus to be where the crosshatch is and raise the camera up.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You need to be further away from your subject. If your camera has macro lens capability, please use it.

    If not, try photographing it in a brighter setting; if you can set F-stop (aperature) priority, set the aperature as small as it goes (highest F-stop number) to improve the depth of field. This will cause shutter speed to be lower than usual. Use a tripod if you have one to avoid camera movement while the image is being acquired.
     
  4. live4soccer7

    Thread Starter Well-Known Member

    Jun 7, 2008
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    So I guess no one can tell what is going on in the picture. I guess I only can because I've seen it in person. lol.. I will try and get better pictures but I can't until tomorrow evening. If anyone has any advice or can see what is going on feel free to throw it out there.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    Well, I can barely make out what looks like three contacts in three loops, the 3rd one doesn't seem to touch. But nothing shows where the bulb connects.

    If it's still installed in the vehicle, try folding the front seatbacks forward, and lie down on the back seat to get far enough away from it. Use a wider field of view.
     
  6. live4soccer7

    Thread Starter Well-Known Member

    Jun 7, 2008
    88
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    it is torn out of the ceiling right now. I tore apart the original insides where the bulb would sit. I wired up the leds on the board that is hanging off to the left. Yes there are three contacts like you were saying. The loop parts. The switch/lever part has a ball on the end of it that will connect two at a time when it is on in one form. It will connect the ground and power at once for it to work. I hope it's starting to make a little more sense. There are two ground contacts and the middle contact is power. When one of the grounds and the power is connected that is always on and when the other ground and the power are connected that is on when door is open. The other setting is when the power is not connected to a ground by the ball on the end of the switch/lever and that is off. I am trying to figure how I can wire leds up to this so that the existing switch system will work with the leds. Thanks.
     
  7. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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    Hmm, wait a minute.

    I think that the switch is actually changing where the bulb received it's ground from; either a constant ground from the chassis, grounds controlled by the switches in the door frames, or no ground at all (off).

    If this is the case, you will want your LEDs' ground (cathode) side connected to the middle (switched) loop, and the + (anode) side connected to the battery side.

    You must use suitable current limiting resistor(s) or current regulator(s) with your LEDs.

    Do you have a schematic drawn up of how you've connected your LEDs thus far?
     
  8. live4soccer7

    Thread Starter Well-Known Member

    Jun 7, 2008
    88
    0
    I can make something like that so that this helps with the situation. And yes you are correct on how it works. It will switch the grounds for when the light is always on and on when only the door is open and it is simply just not connected to the power (middle silver one of the three) when it is in the always off position. What program would you recommend for drawing up a schematic?

    I have tried getting better pictures and it is just not working out. I can maybe draw something up on how it works. I used a current limiting circuit with a lm317. Just as I did on my dash. That way I won't have burn out leds in a month or so from them getting just a tad to much current.

    As a basic understanding on how I have my leds wired up:
    There are twenty leds total, 4 series of 5 red leds, each series with a current limiting circuit (lm317). A power wire is hooked up to all of the input (Vin) on the lm317's and all of the grounds are connected on the leds. So with all that said and done there is a single power wire coming off the board and ground.
     
    Last edited: Jun 18, 2008
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