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Controlling Neopixels with distance between runs
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Controlling Neopixels with distance between runs

by Spaceprimate on Sun Apr 01, 2018 7:49 pm

Instead of running a true perimeter lighting scheme I am trying to run three sets with the longest distance between them being 12ft. So I am trying to run a 20ft run, jumping over 12ft, running a 40ft run, then finally jumping 8ft to a 25ft run... 3 total runs of lighting @85ft.

Now I was told that a Raspberry Pi would be able to run a simple light program across that setup, something along the lines of a knightrider single-pulse type of coding (as the cpu only is focusing on one pixel of info then dumping it), but because I have a 12ft and 8ft span of input runs to the next set of lights anything more complicated than that would “lag” and probably not work.

This would be:
Raspberry Pi, external power along the way, and 60/m Adafruit NeoPixel Digital RGBW LED strips.

Am I out of my element.. like a child wondering into the middle of a movie?

Would I need to run something like Dotstars or separate Pi’s to make this work?


Many thanks in advance for comments and suggestions!

Spaceprimate
 
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Re: Controlling Neopixels with distance between runs

by adafruit_support_bill on Mon Apr 02, 2018 6:04 am

The distance between pixels is limited by the drive capability of the pixel output pin. In general, up to 6" is no problem. With optimal cabling, you can typically get up to a meter or so. Beyond that, you will need some active electronics. Some users have gone hundreds of feet using RS485 line driver chips to boost the signal.

The other alternative is to use a separate controller for each strip with either hard-wired or wireless synchronization between the controllers.

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Re: Controlling Neopixels with distance between runs

by Spaceprimate on Tue Apr 10, 2018 12:23 pm

Thanks for the info! Big help.

One final question:
The 40ft run would need to be powered off a 60 amp breaker “just in case” right?
...I read the article on tweeking power consumption and that the 80mA draw is a worst case scenario but to be safe and just so I’m not tripping breakers constantly.

Again, R/G/B/W 60per meter.

So many thanks in advance!

Spaceprimate
 
Posts: 2
Joined: Wed Mar 28, 2018 7:40 pm

Re: Controlling Neopixels with distance between runs

by adafruit_support_bill on Tue Apr 10, 2018 12:40 pm

60A would be worst-case. Most applications require somewhat less than the worst-case estimate. This guide has some tips on efficient use of power: https://learn.adafruit.com/sipping-powe ... s/overview

But in any case, 40' is still going to be a lot of pixels and a lot of power. So there are some additional considerations for your wiring:

1) To avoid voltage drops and overheating the power and ground rails on the strip itself, you will need to feed power to multiple points along the strip. At a minimum, I'd feed power to each end, and also every 4 or 5 meters.

2) For safety, fuse each feed separately - select a fuse appropriate for the wire gauge you are using.
https://www.powerstream.com/Wire_Size.htm

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