Know LEDs? Help!

[Xaenyth]

I've been muddling over a little project for my Tundra DC for a while now and I've decided I'd like to get 'er done.

The LED taillights that are available now for are the project. They use LEDs for the brake lights but not for the blinkers or reverse lights, which use standard bulbs. What I would like to do is retrofit in amber LEDs for the turn signals and whites for the back-ups. But in addition to this, I want the amber LEDs to make an arrow formation that come on sequentially, like an old T-Bird or Shelby Mustang.

What I need to know is where I can find an adjustable sequencer that I can tie the LEDs into. Ultimately I'd like to add a capacitor to the mix and get the timing right so that when the blinker is providing power, the LEDs come on in sequence, and when the blinker stops providing power, the capacitor drains and the LEDs shut off, also in sequence, making a constant sequence of on-to-off. No doubt I will also need a timer to shut the system off completely when the blinkers are off so that the LEDs don't continually sequence until the capacitor is fully discharged.

I'm pretty handy with schematics, but haven't found one yet that fully explains what I'm going for besides a Knight Rider KITT sequencer. And I have zero experience with circuit board components so I don't know exactly what I'm looking for, though if the parts exist (and I'm sure they do), then I know I can pull this off.

Any and all input would be greatly apprecaited.

Thanks!

[Mr. Creosote]

I've been muddling over a little project for my Tundra DC for a while now and I've decided I'd like to get 'er done.

The LED taillights that are available now for are the project. They use LEDs for the brake lights but not for the blinkers or reverse lights, which use standard bulbs. What I would like to do is retrofit in amber LEDs for the turn signals and whites for the back-ups. But in addition to this, I want the amber LEDs to make an arrow formation that come on sequentially, like an old T-Bird or Shelby Mustang.

What I need to know is where I can find an adjustable sequencer that I can tie the LEDs into. Ultimately I'd like to add a capacitor to the mix and get the timing right so that when the blinker is providing power, the LEDs come on in sequence, and when the blinker stops providing power, the capacitor drains and the LEDs shut off, also in sequence, making a constant sequence of on-to-off. No doubt I will also need a timer to shut the system off completely when the blinkers are off so that the LEDs don't continually sequence until the capacitor is fully discharged.

I'm pretty handy with schematics, but haven't found one yet that fully explains what I'm going for besides a Knight Rider KITT sequencer. And I have zero experience with circuit board components so I don't know exactly what I'm looking for, though if the parts exist (and I'm sure they do), then I know I can pull this off.

Any and all input would be greatly apprecaited.

Thanks!

Hi dude .

I would just use a simple microcontroller at each tail with external FETs to drive the various LEDs with the sequence you want. I would use ignition switched power to the system to get the sequential turn off you describe because the controller should stay powered during the flash and after the flasher has taken power away, but this would be easier than a capacitive / analog method. The latter would also result in quite a few large capacitors needed and a fair amount of circuitry to get crisp, consistent flashing and brightness from the LEDs. Can you draw out the LEDs and how you are thinking they should sequence?

[Xaenyth]

How hard would it be to get constant power to the rear blinker bulbs? I didn't think that was an option else I would've have mentioned it... sure would be making this a lot easier, especially if I can use the 12v from the turn signal to activate the sequencer.

Anyway, what I basically want is a sequence that looks like this:


But if I want to get real fancy with it, I may want them to sequence like this:


Let me know what you think.

Thanks again!

[Mr. Creosote]

That will look incredible.

My compliments on your gif generation in itself.

I would go for the second arrangement. Twelve vertical rows of LEDs to control instead of three, so just pick a controller with more port pins, not a huge deal.

There is one important thing for your consideration since you desire a fair amount of detail in your display. I have a second set of access cab lenses in front of me. The clear plastic in the lens is "corrugated" in its attempt to spread the orange light from the bulb, presumably to make the light fuller and more visible from multiple angles. This may wash out some of the detail in your display, especially the second one.

At the very least you will need to place the LEDs directly behind the clear plastic, as opposed to further back in the lens cavity. Even then, I suggest you get another set of lenses and attempt to test individual LEDs inside them to see if the detail can propagate through the corrugations to your satisfaction.

No doubt you will be able to get adequate candlepower through....it is the ability to actually resolve the arrows and scrolling I am concerned about. I know your lens is different, but nonetheless I suggest looking into this first before proceeding.

On the matter of constant power, at worst you run a single line from the fuse block to the rear area, tucked inside the frame etc. This will not be a large contribution to the overall effort. For a possible shortcut, do you have a hitch with trailer electrical receptacle? Perhaps one of the pins in this receptacle has the switched power needed? Given the low current requirements of LEDs, it may be possible to borrow a few hundred milliamps without issue to the trailer circuitry.

[Xaenyth]

I was planning on getting a set of aftermarket LED smoke lens taillights for my double cab. When they come in I'll be taking them apart to see how the lens looks on the inside. And I was definitely planning on putting the LEDs as close to the lens as possible, even bending the circuit boards to match the curvature. I've noticed some currogation, but not nearly as much as the older style Access Cabs.

I didn't think to tap the trailer receptacle for power. I'll have to hit it with my multimeter to see what's what. Once I do that and the new taillights come in I'll be updating.

Thanks for your suggestions! As for the gif generation... Photoshop/ImageReady is a long time friend of mine.