2 wire LEDs used as Brake-Tail

Discussion in 'The Projects Forum' started by jbhawley, Jan 22, 2010.

  1. jbhawley

    Thread Starter New Member

    Jan 22, 2010
    2
    0
    Hello all. This is my first posting on this forum so please forgive me ahead of time if you have answered this questions many times. I have spent the past couple hours searching this forum for my specific item, but either have not found a relevant solution or the solution posted was waaaay over my head.

    I have a pull behind trailer that has a standard 5 wire connection coming from the vehicle. Ground, Right Turn, Left Turn, Brake and Tail (run). I have added an extension to the trailer and need to add some additional rear lighting. I have purchased these:
    http://www.carparts.com/autoparts/P...Browse/s-10401/Ntk-AllTextSearchGroup?Ntt=LED

    They are simple LED lightbars that have a two wire system. Hot/ground. I have the amber colored lights for each turn signal. This was the easy part..just tap into the existing left and right turn wiring. The red LED bar I would like to use as a brake and turn. I have two red light bars mounted, one under each turn (amber) bar. Sorry, but I do not have any additional info on the lights as they are a sealed unit with no specs sheets.

    From additional reading on this forum, mentioned is 555 boards, resistors, PWM circuits and so forth. Honestly this is a bit over my head. I am a definite noob on circuit boards, so far as building them. As I understand I need to get the LEDs to stay dim while on tail (run) and then go brighter when the brake is applied.

    Is there a simple solution to make my idea work without having to reinvent the wheel?

    Many thanks for suggestions. I have attached a very simple diagram of the set up.
     
  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,170
    395
    Just a thought: Three input OR gate, T current limited by 50 ohm +-, B passes thru shottky diode & P ch MOSFET which is always on if B is on to red;L direct connection to amber & gate, which inhibits B & T while L is flashing, if B is off L lights red. Same ckt for R. Gste resistor about 1k.
     
  3. jbhawley

    Thread Starter New Member

    Jan 22, 2010
    2
    0
    I think I figured it out. Being a noob to this, i went to Radio Shack adn purchased a couple diodes and some resistors. Total cost less than 10$. I knew I needed a diode to "block" the backfeed current that would come from the brake lite. I experimented with the resistor to "lessen" the current coming into the LED with the tail lite was on. Then when applying the brake the LED lit to 100%. It took a bit of tinkering but works good now.
    Here is a real simple image of my set up.
     
    • pic.jpg
      pic.jpg
      File size:
      39.5 KB
      Views:
      37
Loading...