New Automotive Build: Looking for Input and Advice

Hey folks. First a little hygiene: please let me know if there’s a better place for this post. This is my first time on the forum. Happy to delete and repost.

I have been playing around with an idea for a couple of years: making an LED array that fits over the rear engine bay of my rear-engined car. (A '14 C2 if you’re curious.)

This project is pretty complex, but I think I’ve gotten my CAD and programming skills buffed up enough that I can take a swing at it. But I’m still very much a tinkerer, and would welcome some suggestions, especially around hardware and power.

The car as it comes from the factory has a plastic, louvered (static) grille or “deck lid” that recesses into a flip-up aluminum engine cover. This grille is made of what I believe to be injection molded ABS and houses a powered third brake light. While the engine itself is directly below this grille, it’s more for general purpose ducting and (in other models) air intake, so I am taking this as a possibility that even with the addition of lots of ambient heat, I should still be able to make an LED array that will…not melt into my engine bay.

The current prototype I am working from is just a sheet of curved sheet metal that fastens to a spare engine cover for fitment and testing purposes. If I can get a good version 1, run some heat and vibration tests, etc., then I’ll make it look prettier in the future.

The LED matrix will be sitting atop a couple dozen fins (or strakes) that will sit more-or-less vertically as oriented to the front-back axis of the car. This is to replicate the look of other OEM deck lids, as well as allow some air movement to and from the engine bay.

The end result is to have an LED matrix, animated/controlled by PixelBlaze, receiving input from the car with synced animations. (Just RPM data to start, but I have some ideas for brake input, G-meter, perhaps even outboard sensors.)

The input from the car will be spoofed on the workbench, but will likely end up being captured by an ESP32 or Arduino box reading directly from canbus and sending signal over Wi-Fi to the LED array. (I will hardwire data lines if necessary; it’s not a hard car to run cabling in.)

While it would be easy enough to tap 12v power from the harness, I suspect the relatively high amperage will require me to build a separate power unit (a battery pack or similar). Fortunately, since this is just a silly project, it’s not something that needs to operate every hour the car is driven, so I have some flexibility there. (I will likely be keeping the stock 12v third brake light wired directly into the harness since I do not want to have to have the array powered to keep the legally required brake light operational.)

In short: ~24 In-line LED strakes forming a matrix. Standalone battery power system. (For now.) Data over Wi-Fi. High UV, moisture, and heat environment.

What I’d love input on:

  • What is my best addressable LED option here? Smaller and denser-per-inch is better. WRGB is preferred, but not mandatory. Will likely need to have PCBs made and am open to that, but will likely hand wire the prototype. Is one type of LED more heat resistant than another? (They will be enclosed in a diffuser, eventually; I could build in heat sinks, if necessary.)

  • What would a good LED-per-strake target be? Obviously the preference is “as many as possible,” but power and physical space will be limiters. 24 x 48? 24 x 10? 24 x…1,000? Draw is the factor here as much as anything, I suspect.

  • I will wire the strakes modularly, so if I have a failure on one (or a set, if that’s how I wire) I can replace units. Is there any advantage to having multiple PixelBlazes here or is it unlikely I’ll have enough total LEDs to make frame rate, etc. a problem?

The #1 piece of advice I’d love to get is really about LED selection. If you know what product lines would be the most likely choice for me I can order some and get to testing. (I have a PixelBlaze v3 Standard on hand already.)

Thanks so much.

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