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Topic: How to proceed: long run of individually addressable LEDs (Read 152 times) previous topic - next topic

y2j514

I want to run a pretty long run of individually addressable LED strip around the perimeter of my yard, attached to my new fence.  I have about 180 linear feet of fencing that it would need to follow.

I have been researching, and it seems like strips of WS2812B controlled by an arduino seems to be the way to go.  I have never used an arduino before, nor do I know any C+.  I have spent that past week learning more and more about arduinos and programming them.  I am about to order a starter kit to play with.

I am not set on this configuration if there is a better solution, but it seems to be the logical way to go.  However, I have been reading that the Uno can only handle about 400-600 LEDs.  185 feet is about 57 meters, with 30 LEDs/meter that comes to about 1710 LEDs (or 5130 LEDs if you count each LED as 3 (RGB)).

I am aware that I would have to tap into the power rails along the way as DC voltage would drop  too much as it travels that far, but would the data from one digital pin from an arduino be able to travel that far? If I have to use more than 1 digital pin from 1 arduino how would I do that so it is seamless, or would I need to use multiple arduinos?

Any suggestions / ideas?

Thanks so much.

CrossRoads

With WS2812B, the data travels from LED chip to LED chip.
Where you run into a limit is how the data is stored for each chip. Each chip needs 3 bytes. If you are just going to send the same color to each chip, that's easy, just send the same 3 bytes over and over until they all get it.
The other issue folks run into is frame rate.  Everytime you want to make a change, you need to send the data for all the LEDs out again, and that means all 5000+ bytes. So if you're going to send some kind of pattern out, make sure it's something you can create on the fly, or use a 1284P with 16Kbytes of SRAM memory, or as 2560 with 8 Kbytes of SRAM memory.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

y2j514

Thanks for the reply.  I am aware that the data travels from one LED to the next, but I wasn't sure if distance would be an issue for the data as it would be for the power rails.  That is good news.  I do want to do patterns and not just the same color, otherwise I would use regular non-addressable LEDs.  By "on the fly" patterns do you mean something the arduino can do mathematically with a for loop?

I have a few other "issues" I need to iron out.

1) I need to learn the FastLED coding, so I can make some nice patterns. 
2) I need a way to control which pattern will be displayed.  Are there any iOS apps that could be used here?


With this many LEDs and needs would a Raspberry Pi be a better option? I have no experience with the Pi either.

Thank you so much for any and all help!



TomGeorge

Hi,
You can feed power to the LED strip by running a backbone pair of power wires and tap into the strip at regular intervals to minimise volt drop in the LED strip.

Tom.. :)
Everything runs on smoke, let the smoke out, it stops running....

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