2 wire LEDs used as Brake-Tail

Thread Starter

jbhawley

Joined Jan 22, 2010
2
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.
 

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Bernard

Joined Aug 7, 2008
5,784
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.
 

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Thread Starter

jbhawley

Joined Jan 22, 2010
2
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.
 

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