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LED tail lights.

ELECTROMAN

May 18, 2012
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I want to build LED tail lights for my truck. I have the LED's and the resistors, LED's are 5mm and have 2v of forward voltage and the resistors are 200 ohms. I need help on how to make the LED's get brighter when the break pedal is pressed. Each tail light is going to have 50 LED's. Please give detail.
 

duke37

Jan 9, 2011
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I am sure that you do not want the LEDs to break when the pedal is pressed!

Vehicles in the UK used to have rear lights that increased in intensity when the brakes were applied. They were a disaster and caused many accidents.

The brake lights should be in a different position to the running light so that it is clear that the brake is applied. If all you do is vary the intensity, how do you know whether the brakes are on if you do not see the intensity rise?

High level central brake lights are more visible.
 

BobK

Jan 5, 2010
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Do a search, this exact issue was discussed on this board recently.

Bob
 

roltex_rohit123

Oct 12, 2009
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one thing you can do. give a seperate connection to 20 lights on your headlamp. for the rest 30 should be on your brakes. now just replace the tail light with LED's use transparent red LED's or SMD LED's. The SMD's are compact and very bright. use 3-4 laser LED's also. the benefit is that they will make the rear viewer realise the difference. use Light covering re in colour so that the laser does not cause problem to the viewer. depending on the voltage 1K resistor is enough for 12V irect battery. you get a strip of LED SMD for decoration. you could modify that. just change the series to parallel and add resistors. or even DC 12v strips are available. this will give you a good look in a compact structure. it is very heap too.
 

CocaCola

Apr 7, 2012
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I agree. Isn't shinning a laser on someone an assault?

Could be, it could also violate many other local laws as well as just being stupid and a hazard in itself...

As said the tail light should consist of two banks of LEDs, one banks is the driving lights the other is the brake lights... When driving only one bank is on, when braking both banks are on to give the higher intensity...

As I said in another topic here if you want to get fancy (it probably violates DOT and local vehicle code though, but so do LED upgrades as most are not approved to start with) is to put a few self flashing/rotating RGB LEDs into the braking bank so there is some eye catching 'wave' like movement when the brakes are applied, it's subtle but it does catch the eyes... I have done this in a few of the lights I have made, I came up with the idea after my dad has been rear ended multiple times on his motorcycle when slowing down and braking and wanted a way to make braking more obvious... Using a few rotating RGB LEDs creates just enough change in intensity that it's eye catching but not distracting...
 
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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Yeah, I remember a circuit that flashed the brake lights 3 or 4 times when the brakes were applied.

If legal where you are, then certainly an eye catcher. I think the rate was around 3 Hz.
 

donkey

Feb 26, 2011
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its odd but certain lights aren't technically legal here in australia. take for example HID. they are allowed on cars, but only if they came with them new. IF you convert them they are illegal.
it is best to check legalities first, unless this is for offroad fun.
 

CocaCola

Apr 7, 2012
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its odd but certain lights aren't technically legal here in australia. take for example HID. they are allowed on cars, but only if they came with them new. IF you convert them they are illegal.
it is best to check legalities first, unless this is for offroad fun.

It's the same in the United States but it's one of those laws that is largely ignored (in most places) but that doesn't mean you won't be busted or that it won't be used as an excuse to harass... Same with most aftermarket LED exterior upgrades, most are not DOT approved and thus not technically a legal replacement or upgrade...
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Yes, in theory you can get a yellow sticker for having no tail lights, but a red sticker for having LED tail lights.

Curiously, working tail lights can be worse than no tail lights at all.
 
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