Sequential LED tail lights - Can someone design me a circuit?

[RPMS]

Hey, guys!

 

Like many others on here I'd like to wire up my tail lights for LEDs, but I'd REALLY like to have the turn signals blink sequentially. Not the "1...2...3...off" sequence like a 1968 Cougar (okay, so maybe you're an old fart if you recognize that reference!) but "1..1+2..1+2+3..2+3..3..off" so the lights chase from the inside out. I'd also like to use four groups instead of just three.

 

Is anyone enough of an electronics wizard to help me design a solid-state circuit that will do this? I'm handy with a soldering gun and am capable of making a fairly simple circuit board with a small ic chip.

 

Anyone? Anyone? I promise a full writeup with pictures when I'm done!

[ZZZeee]

* lurking in this thread *

[jasper]

I worked on the cougars, and tbirds. I know the system and how it's done mechanicaly. Very simple.

[junglist]

Hell, does anyone even do the LED taillight conversion anymore? I'd be willing to ship someone some taillights (thats done it before) and pay a reasonable amount to have them converted.

 

I know Pallnet used to and a guy from ClassicZcars.com used to also. I wish we could get a groupbuy for some LED taillights from some chinese knockoff company that sells them on ebay but there would probably be nowhere near enough demand.

 

EDIT: Just found this link: http://cincitydesigns.com/ - I'm going to contact him to ask a price.

[2fast2Z]

a guy from ClassicZcars.com used to also. .

 

Search for Zsondabrain, he still makes them.

 

Chris

[Trevor]

http://cgi.ebay.com/ebaymotors/Parts-Accessories___Mustang-Sequential-Taillights-96-97-98-99-00-01-02-03-4_W0QQitemZ330293825457QQddnZPartsQ20Q26Q20AccessoriesQQddiZ2811QQcmdZViewItemQQptZOther_Vehicle_Parts?hash=item330293825457&_trksid=p4506.c0.m245&_trkparms=72%3A543%7C65%3A12%7C39%3A1%7C240%3A1318

[RPMS]

I worked on the cougars, and tbirds. I know the system and how it's done mechanicaly. Very simple.

 

I seem to remember that the system used back then was a motorized unit that moved a contact along a series of conductors, closing one circuit after another. It was an interesting solution! Hopefully someone on this board can help me use solid-state devices to achieve the same effect.

[RPMS]

Just found this link: http://cincitydesigns.com/ - I'm going to contact him to ask a price.

 

 

COOL! Please let us know what you find out. Even if they decline to help us, it would be valuable information for those who search for this information later.

 

I'd consider doing the conversion for other people, but it would be a pretty hefty price. Heck, just the lights are going to run about $90. Drilling 150 holes and securing/wiring that many LED's is going to take a lot of time. I want the entire lens to illuminate evenly, not just a hot spot in the middle.

[ZZZeee]

I've though about installing a couple of those small outside (bright) tri-color LED signs in place of my turn/stop/running lights. The colors are red, green, and yellow which is enough for anything needed on a car. Those come with animation software that can be customized and downloaded to the signs. The RGB version would be very cool but I don't think there are any bright enough... plus they're quite pricey compared to the tri-color versions.

[RPMS]

I've though about installing a couple of those small outside (bright) tri-color LED signs in place of my turn/stop/running lights.

 

If you could make that work, it would be infinitely cool. I can imagine the entire tail panel replaced with a multipurpose animated LED screen. Imagine the messages you could send to tailgaters!

[ZZZeee]

You could probably canibalize the recent Mustang rear tail lights with this feature but I don't know which model/year and/or option this was. I've only seen a couple 'Stangs with it in the last several years.

[ZZZeee]

If you could make that work, it would be infinitely cool. I can imagine the entire tail panel replaced with a multipurpose animated LED screen. Imagine the messages you could send to tailgaters!

 

Yup... haven't we all wanted to send "special messages" to those who deserve a harsh textual spanking?!

 

The power can easily be provided by either by-passing the internal AC-DC power supply if the internals are run off of 12v DC or with the use of a simple inexpensive 12v DC to 120v AC inverter if not. It's the cosmetic integration that may pose a challenge. But there are many creative folks here and I'm sure someone can easily accomplish the job.

 

I'm lazy and would buy a turn-key offering.

[mikeatrpi]

Well, for the circuit you can start with a simple 555 timer to build an oscillator. You can choose the capacitors from the datasheet, and use a potentiometer to adjust the blinking frequency (the speed of the chasing lights) to suit your taste. If you ever wanted to mass-produce these you could replace the pot with a fixed resistor.

 

Then you can use some TTL gates or better yet, a decade counter IC.

 

I doubt the counter can source a lot of current, but you can use it to drive a transistor, then let the transistor sink the current for the LED's. If you use a decade counter it will give you 10 outputs, which pulse sequentially at 1/10th the frequency given by the 555 oscillator. You'd have to do the math to determine the maximum load per transistor and divide up your LEDs amongst the 10 circuits.

 

Keep in mind, the decade counter will not do exactly what you want.

 

A Gray code counter might get you closer. IE, 00, 01, 11, 10 where only one bit changes at a time. Drive each bit to the respective transistor / LED outputs. 000, 001, 011, 010, 110, 100, 000 is another Gray code. Again not exactly what you want.

 

Or for the ultimate flexibility maybe you want to use a cheap microcontroller, such as an Atmel flash based IC. Some of them have their own oscillators built in with enough precision for this type of thing. You can whip up some C code to drive (or sink) the outputs as you wish. You can definitely make this do precisely what you want.

 

These sites should get you started on the decade counter / 555 timer idea:

http://www.qrp.pops.net/LEDs.asp

http://www.doctronics.co.uk/4017.htm

 

For the Atmel chips, go visit http://www.avrfreaks.net

[RPMS]

Well, for the circuit you can start with a simple 555 timer to build an oscillator. You can choose the capacitors from the datasheet, and use a potentiometer to adjust the blinking frequency (the speed of the chasing lights) to suit your taste. If you ever wanted to mass-produce these you could replace the pot with a fixed resistor.

 

Then you can use some TTL gates or better yet, a decade counter IC.

 

Wow... Uh... I suddenly feel overwhelmingly ignorant.

 

I shall dive into the links you have kindly provided, and see if I can't edumacate myself a little bit before Granny brings in the possum stew for lunch.

[RPMS]

Keep in mind, the decade counter will not do exactly what you want.

 

Thank you VERY much for the links, buddy! I'm having a great time puzzling through this all.

 

Looking at the website for the decade counter, I don't understand why it wouldn't work for what I'm envisioning. Say I have four lights I want to illuminate in sequence 1, 1+2, 2+3, 3+4, 4. Couldn't I hook up light #1 to outputs 0, 1 and 2, hook up light #2 to outputs 1, 2 and 3, light #3 to outputs 2, 3 and 4, and light 4 to outputs 3, 4 and 5?

 

Or does it not work that way?

[mikeatrpi]

Scott - here's a quick reply! You caught me on my lunch break. Didn't mean to call you simple - I meant the circuit only needs like 4 other things. Its not a monster.

 

Your idea should work. Good thinkin'. You might want to put a diode on the outputs to keep the output of "0" from becoming the input of "1". I'll google up a data sheet on these parts and see if it would even matter if you want. The other methods (Gray code, microcontroller) wouldn't require the diode.

 

So how would you power this thing? I'm not too familiar with using LEDs for tail lights. Are they +12v? These circuits are TTL and operate at +5v. You'd need to factor in a 7805 regulator as well. You can use +12v transistors to drive your LEDs as long as +5v (-0.7v if you use a diode on the output of the counter IC) is over the Vt of the transistor. Simple right?

 

Let me know if you need some more help. I can draw up a little somethin' for you if needed.

 

Enjoy the stew...

[fear_me]

The 555 timer is easy here is an example:

If you had a plc i could do it easly.....

else this will take some thinking.

mikeatripi is on the right page i think you will need some type of counter....

hmmm, like a segment counter.. then just use the outputs to trigger trans. and when the number is say 4 it can be reset....

interesting idea... just needs some thinking.

 

~Andrew

[fear_me]

was just thinking, how about a shift register? there has to be one that will work for him.

 

~Andrew

[Jon 74 260Z]

Errrr...., you can use a microcontroller and all this grey-code nonsense if you want to BUT....

 

What you really should use is an LM3914.

 

Scrap the 555 and the microcontrollers -- the simplest solution is the best.

[mikeatrpi]

What you really should use is an LM3914.

 

How would you integrate this display driver to generate the sequence he wants? It takes an analog reference voltage and chooses the display based on the level. Are you thinking of using the 0_/---12v transition from the flasher? A (dis)charging circuit?

 

 

Anyway, according to Google you can supply a 555 timer with between +3 and +15v. Same for the 4017 decade counter. That means you don't need the 7805 regulator.

 

There's a traffic light sequencer at the bottom of the decade counter link. That shows the diodes forming a "dotted" OR gate. That should help you devise the output circuit.

 

I'm sorta leaning towards the microcontroller here, because you can solve a bunch of problems with code. For instance you want to make sure it always starts at the 0th light and always ends at the last light, you don't want half-sequences - it would look stupid. You can also use the controller to dial in the right frequency.

 

I need to think about it some more.