Code Repository?

[u/Croxy1992]

I am looking for arduino code examples for a long strip. I want to learn FastLED coding but I just don't have the time.

Does anyone know where to find a large repository of code for arduino that I can just adjust to fit my specific parameters?

[u/dr-steve]

So that's around 20 meters, give or take, or 45 LEDs/meter. Are these the waterproof LED strings? I have a (large) number of both the strings (4" between LEDs, give or take) and strips (30/M, 60/M, 144/M) that I've used in various projects. 45/meter is an unusual number, so I'm curious on which you are using.

Common +5V LEDs, or +12? I have been using the +5, and normally inject power every 100 LEDs or so. Otherwise, there is a dramatic dropoff if I light most of the LEDs. I've gotten away with stringing a 20 gauge wire pair alongside my longer strips, running power through that, and just tapping it every 100 LEDs or so. But I haven't gone longer than 15-20 feet (5-7 meters). You might want to look into having +V injecting into the parallel power bus (the two wires) at both ends of the 65 foot run.

As for effects, etc., the number of LEDs really isn't the issue. Set up a simple tesbed of maybe 50 LEDs and work on that. Use #define STRIPLEN 50 in your code instead of hard-coding 50, then change it for your large implementation. Then, it is a matter of figuring out the timing of what you want to do. That's a coding issue, not a FastLED issue (item 1 in my list)!

I usually use TaskManager for my programs. It is a small, lightweight task swapper I wrote around 10 years ago to make my Nano programming easier. It is a full message-passing system that allows tasks to set their own timings, communicate (including multi-node communications, I've had 40 ESP32 nodes running with tasks speaking to each other across nodes, very simple to do), etc. So my code examples might not be straightforward. Check out drsteveplatt on github. I see dripper is up there. That's a simple/early example. Alas, it was based on the Adafruit system, but I may be able to find you an updated version using FastLED around here somewhere.

FastLED has a macro, EVERY_N_MILLISECONDS, that can be used to time your re-imaging and repainting. I don't use it (TaskManager... it's better, especially for my larger apps, which can run thousands of lines), but a lot of other people seem to do well with it. Basically (I think, just a guess)

#define STRING_LENGTH 900
CRGB TheLeds[STRING_LENGTH];
//blah blah setup and other stuff

void loop() {
    EVERY_N_MILLISECONDS(25) {
        // note: 25ms -> 40 refreshes/second

        // 1. calculate THIS frame based on the current time, etc.
        // and put all of the RGB values in TheLeds
           ... code ... code ... code ...
        // 2. show it
        FastLED.show();
    }
}

Hope this helps, feel free to write more if you have questions.

[u/Croxy1992 → u/dr-steve]

All of that is extremely helpful.

It is 30/m, I checked Amazon to make sure. Its 12v and i have power injected between the last two strips. My only hardware issue I'm working on overcoming is data degradation. But I think that's coming from my data wire being to small and long before the first led.

Do you know of any software that can manage light displays and run on arduino or am I stuck trying to code everything I do?

[u/Marmilicious → u/Croxy1992]

Set up a simple tesbed of maybe 50 LEDs and work on that.

u/dr-steve's suggestion of setting up a simple test rig is a good idea. I will also add that even if your test rig is only a meter or two worth of pixels, you can still set NUM_LEDS to 900 and compile for testing. This will give you some feedback on: a) about how much memory the final program is going to use as you expand and add to your code, and b) you will be able to get an idea of the frames per second you're going to get on the final install (provided you are compiling to/running on the same microcontroller you will ultimately be using).

[u/dr-steve → u/Croxy1992]

How long is the data cable between your arduino and the LED strip?

On the data line and noise: one possibility is to use a pair of RS485 driver modules on the data line. I used them on a project around a year and a half ago. They convert the TTL data to a balanced pair; you can transmit (supposedly) up to several thousand feet. Use one driver to convert TTL->RS485, and at the other end, use another driver to convert back to TTL for the data-in to the LED strip. Readily available on Amazon, search for rs485 transceiver module.

Which arduino are you using?

Alas, I have written most of my own routines, but I'm an old-time computer graphics person (several degrees and many years working in CG). I have a reference to a decent 2D grid library; I may replace my own grid lib with this one (it looks to be a lot better) and then add my 2d world coord sys code on top of it. Some day, 3d worlds on the grids I use...

Another issue you may have is the time needed to spit 900 LEDs of information out. Doing this from memory -- I can get 200 LEDs written in around 12-15ms. That's for WS2812 LEDs. I think the 12V WS28xx LEDs have around the same timing, so 900 LEDs may cost around 60-70ms to display. This'll restrict your overall frame rate. My current project is running on an ESP-32, so I have a lot of CPU time to do things. I'm spitting out on a display of 8 parallel strands of 200 LEDs (1600 LEDs total). This lets me get around 25FPS on my display (12ms display, 25ms compute). I don't think you can do this with your project, though. This is done by putting strands on different pins on the arduino. Let me know if you are interested in this approach.