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Discussion Starter · #1 · (Edited)
Hi guys!

I'm sorry I didn't come back on this forum sooner but I travelled a lot this summer, for work unfortunately... Anyway!

If you like the Mustang sequential taillights, then you might like this thread! Because I’m planning on DIYing the same thing on my 300M!

First of all, this is still a work in process, so you should wait until I edit this first post to mark my work as done, before doing anything to your car.

PROJECT STATUS: FIRST STEP just began.

Basically, this project will be done in three steps: led retrofit, sequential module design, and sequential module integration.

First thoughts:
I’ve been thinking of this for a while now, and I’ve come through different designs in my head and on prototype boards. Initially I wanted to make 3 to 4 led modules per side, composed of 1 high power led in the center of a radiator, and 3 powerful wide angle “classic” leds around (glued in the drilled radiator), forming a triangle where the high power led would be inside. Sounded cool but I had to drill the radiators, and actually it wasn’t as easy as I thought… Broke 2 drill tips, made me crazy, and I'd have to crack open the taillight assemblies to get the modules in!
Then how could one control the leds sequentially… I tried using a CD4017 chip, controlled by a CD4060, itself being controlled by a crystal. That worked well on the paper and on the computer, but I couldn’t get the prototype board to oscillate properly! FAIL-OF-THE-MONTH’s for me…

My design for now:
Drilling and fitting 1+3 leds went to gluing one single high power led on each radiators (for now).
Powering the leds with a “raw” 12v is not possible, you must limit the current. Different options here, the humble resistor inline but the current might fluctuate causing the leds brightness to fluctuate also. 2nd option: a more advanced “constant current source”. I won’t go into details on this, you’ll find everything you need here: High Power LED Driver Circuits by Dan on Instructables.com
Powering each led at a time will be done by a microcontroller, an Arduino first, then maybe an ATtiny if I can find one with 6 PWM pins. The µC will control 6 constant current sources which will be feeding the leds.


I'll post links to the different steps here:
1. Preparing the first taillight assembly, retrofiting leds, and first test.
 

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Discussion Starter · #2 · (Edited)
FIRST STEP: LED RETROFIT

Ok let’s dig further and get our hands dirty ^^

1. Remove the taillight assemblies from your 300M.

2. Mark some beacons on the bulb plugs and take a picture to make reassembly easier, then remove the bulbs and the wire harness (will be easier to work on the assembly this way).


3. Now take your Dremel and start drilling into the plastic \o/ I used a very thin “drill tip” and drilled multiple holes, drawing a circle. With some patience you’ll get a good result. See the “eyelets” on each holes? They are for the led pins to fit in.


4. Put the leds in place to make sure they fit. If they do, then put some thermal paste glue on the led heat sinks and put the radiators on top. Press gently on the radiator to spread the glue. I used this cheap thermal glue from DX.com and a bunch of 3x3x1cm radiators from digi-key I think.

5. Now the leds are glued on their rads, it’s time to solder some wires. I used wires from an Ethernet cable.

6. Wait a bit for the glue to cure, then put the leds back in place. Secure them to the case with some tape (as a temporary solution) and wire everything together. The constant current source I designed should limit the current to 670mA (with R3 = 0.75 ohms) whatever the voltage drop is, so I wired the leds in serie for my test.


7. Power the constant current source driver and admire your hard work! First two pictures are no flash then with flash. Then I decided to lower the current down to 250mA (R3 = 2 ohms) to decrease temperature and brightness (picture taken without flash).


Next step, redoing everything on the right taillight assembly, and building another temporary constant current source so I can drive my car. Then I’ll have to build the sequential driver and rewire the leds.

Stay tuned!
 

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Looks like a nice project, Remi.

An alternative to the current regulator is a voltage regulator and resistor. More temperature stable and simple than Dan's current regulator since voltage regulator devices are optimized for constant output (internal voltage reference based for very little temperature dependence). The resistor and regulator would be absorbing the waste heat instead of mostly the MOSFET. Since both methods are linear, net losses would be the same.
 

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Discussion Starter · #4 ·
An alternative to the current regulator is a voltage regulator and resistor. More temperature stable and simple than Dan's current regulator since voltage regulator devices are optimized for constant output (internal voltage reference based for very little temperature dependence). The resistor and regulator would be absorbing the waste heat instead of mostly the MOSFET. Since both methods are linear, net losses would be the same.
Do you mean a LM317 or a 78xx in line with a resistor?

I have been working with 78xx and they need a supply voltage 3 volts above their output, and you have to add capacitors to filter the input.
I was talking about the led temperature... Running at 670mA, it get's hot quickly and I don't want the taillight assembly to melt before even using it on the road ^^
 

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The newer design regulators have much smaller "dropout voltage". Use the drill down feature of www.digikey.com and you'll see what I mean. The higher current ones in general do have higher dropout requirements, but there are some exceptions. I'm not sure how much current you're needing, but the Diodes Inc AP7173-SPG-13 (adjustable) has a regulation dropout of 0.165V at 1.5A. There are others. A lot of the newer stuff is surface mount, and of course, commercial design leans more towards switchmode regulators for efficiency, so selection in linear through-hole regulators is becoming less and less.

How much current are you going to need on one circuit?

Something to think about: Build only *one* positive source (either constant current or fixed voltage with resistor) and have the controller drive one transistor to ground each LED circuit in sequence. That way you only have one positive source to design and build, so a lot less parts total. (or one positive current-limited source per side)
 

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Discussion Starter · #6 ·
You, man, are awesome!

I don't know how much current I need because I want to compare brightness with a normal bulb before...
But I dind't think of having only one regulator then 3 transistors to ground each led!

This is mostly a proof of concept, a first test. I'll post a video if I can manage a way of getting a fine video of the OEM assembly and the custom one side by side.
 

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Discussion Starter · #8 ·
Wow! Nice results!

The bad thing is... I live in France now, and I'm limited by stupid laws like "blinkers must be orange", and "blinkers, stop lights, position lights, fog lights must be separated, and cannot be used together in any way".
Tuning possibilities are limited here, my mod is not even legal anyway ;)
 

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You, man, are awesome!

I don't know how much current I need because I want to compare brightness with a normal bulb before...
But I dind't think of having only one regulator then 3 transistors to ground each led!...
Glad to help. 30+ years of circuit design ought to count for something. :)
 

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Discussion Starter · #10 · (Edited)

First comparative test! Left side is LED retrofited running at 500mA, right is still intact.
I kept the constant current source design for this test because I already had all the parts. However I made two nice and compact regulators, way smaller than the first one.

It was very dark already and it's hard to judge how bright it is... It's only running at 500mA and it's way brighter than the original right bulb.

I'll post a better video asap.


By the way, I secured the LEDs to the headlight assemblies with some Loctite 595 (clear silicone), as you'll see here:



 

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Making progress! Looks good.
 

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Discussion Starter · #12 · (Edited)
Yes! Got it working!!!

After spending HOURS searching for the nice GX16-8 connectors I bought in november, which were actually hidden way down the trunk of my M (you know, between the back seats and the trunk's floor carpet)... And after a few soldering job, I got my sequential taillights to work!

I kept my original design, one current limiter per channel making 6 limiters in total, and 2 controller boards.
Each controler board is made of:
  • 3x constant current drivers
  • 1x LM7805 voltage regulator for microcontroller power
  • 1x PIC P12F508
  • 1x Sequential patern disable switch

Each current driver is made of
  • 1x 100k resistor
  • 2x 0.68 ohms resistors (set the current to about 350 mA)
  • 1x IRF640 mosfet
  • 1x BC547B transistor

I already had the parts, so...

The controllers do work... However the left side's switch doesn't do its job, I can't disable the sequential patern... But I think my friend Robin and I didn't upload the good firmware ^^
Units look bulky,and they are! PCB boards come from DealExtreme.com and are, well, cheap... So I woulnd't be surprised if they fail... I had troubles soldering components, traces wouldn't stick to the boards.

I'm sure I took pictures of the controlers (one board per side) a while ago but I can't get my hands on them... Maybe they're on my old phone... So more pictures to come ;)

Because of the reliability of the PCBs, I'm sure I'll have to redo everything one day. At his time, I think I'm gonna go the "Peva's way" with voltage regulators and resistors ;)

Meanwhile, here is a video of the sequential taillights :)

 

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Good work...like to see the ingenuity of the mods!!
 

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Discussion Starter · #17 ·
I'd love to!
But french laws (and damn french cops) don't allow lightning modifications... Clear 01+ tails would clearly show the mods, and would be a great way to loose money here (and maybe my license, or at least my car, temporary) :(

My mod here is not legal neither, I know... But a little more difficult to identify for a cop, unless they follow me WHEN I'm turning...
And I'm going to route a switch to the glovebox or something, so I could disable the sequential pattern while driving ;)
 
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