Attempting to Run 500 LEDs from cars 12v source

Projects General Guidance
1

Hello, Im looking to install an underglow for my car but I want to be special and be able to program the LED show under my car. I will be using Adafruit NeoPixel RGBW LEDs a 150w 12v DC to 110v ac coverter and a 5v 40a Power supply

I have found:
My car will use about 14 meters (44' 2") of LED strip
Each LED is 80mA at full brightness
there are 30 LEDs in a 1 meter Strip, So 2.4 amps per meter
so for 14 meters * 2.4a = 33.6a
so that would be 420 LEDs needing to be controlled
Using Ohms Law I have found to power the LEDs at 5v, 40a would give me a resustabce if .125 and 200w needed

I figured use 40a just for a little back support

But so from using Erik Katerborgs [Website](https://www.eerkmans.nl/powering-lots-of-leds-from-arduino/) I have found that the arduino mega can only power 1 meter (30 LEDs) of LEDs. I have looked into the [Fade Candy](https://www.adafruit.com/product/1689) and found that it would be the perfect controller 3 channel for each door side, 1 channel Front, 1 Channel Rear... Just enough to power the entire Underglow.

So I solved my original question while typing this out, so I guess my next question is: would there be a way where I could have an app or switchs with pre codded light shows so I change the Lights pattern on the go.

Oh and im currently unsure of how I would add a switch to turn the system on and off as it is illegal to drive with under glow in my state

Thank you guys if this was a bit confusing im sorry, im a senior in high school and only self taught for now
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The use of Your proj is illegal in Your state. Where do You intend to use it? Inside the garage only?
Illegal stuff is not promoted here.
Will the alternator manage to handle that pwr consumption at the same time as the other needs of the car ?

3

If you don't need 110V for anything else, I'd look for a DC-DC converter.
[u]Here is one[/u] rated for up to 3A, so if you are going to cut the LED strips you could use multiples. (My quick search didn't find any rated for 40A.)

But so from using Erik Katerborgs Website I have found that the arduino mega can only power 1 meter (30 LEDs) of LEDs.

The LEDs are not "powered" directly from the Arduino. The limitation is memory. You have to store the 3-byte RGB value for each LED, plus you need memory for your code and whatever NeoPixel library you're using.

There is voltage-drop over then length of the strip, so you should make a power connection about every meter (or at both ends, etc.). It's usually the same power supply, just separate heaver-gauge wire compared to what's built-into the strip.

You can run the data line to multiple strips if all of the strips can have the same pattern. That will save on memory (and programming).

So I solved my original question while typing this out, so I guess my next question is: would there be a way where I could have an app or switchs with pre codded light shows so I change the Lights pattern on the go.

Adafruit seems to be the best resource.

If you can understand how to use the library you should be able make any kind of pattern/sequencing that you can imagine.

Oh and im currently unsure of how I would add a switch to turn the system on and off as it is illegal to drive with under glow in my state

That's not too hard so I'll let you research how to wire an on-off switch. I'd wire it to turn off "everything". i.e. If you use the 110V converter, turn-off the 12V to the converter. You could also turn-off the LEDs under software control but your converter and/or power supplies will still consume some power.

I have looked into the Fade Candy

I think that needs USB connection from a computer so it won't work with the Arduino. But, maybe it can store patterns and run stand-alone, I don't know.

4

Railroader:
The use of Your proj is illegal in Your state. Where do You intend to use it? Inside the garage only?
Illegal stuff is not promoted here.
Will the alternator manage to handle that pwr consumption at the same time as the other needs of the car ?

I plan on using it at car shows, you can have underglow Just not while driving. But yes, I did make sure my alternator could power it (aka I upgraded it already for my stereo)

5

That's okey. Watch out for the need if currentconsumtion.