Maximum NeoPixels Driven by one pin?

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computersarecool
 
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Maximum NeoPixels Driven by one pin?

Post by computersarecool »

Hi,

I am using the NeoPixel library and I currently have 5m of the 96 leds / m strip of neopixels. My question is if I can connect all of their data lines together and, in my sketch, say the strip length is 96 * 5 = 480 pixels per strip, or if there is some sort of maximum. Make one long strip would make it easier for my sketch, which is why I want to do it this way. Thanks

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adafruit_support_bill
 
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Re: Maximum NeoPixels Driven by one pin?

Post by adafruit_support_bill »

The maximum is limited only by memory. It takes 3 bytes per pixel of SRAM. An UNO has 2K of SRAM some of which is also needed for the program stack and other variables. A Mega has 8K.

computersarecool
 
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Re: Maximum NeoPixels Driven by one pin?

Post by computersarecool »

So distributing the strips among different pins would have no effect on this RAM consumption correct? (i.e. it does not help to spread them out)?

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Franklin97355
 
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Re: Maximum NeoPixels Driven by one pin?

Post by Franklin97355 »

No, that does not help. It still takes 3 bytes per pixel.

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adafruit_support_bill
 
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Re: Maximum NeoPixels Driven by one pin?

Post by adafruit_support_bill »

There may be a few bytes more overhead associated with each additional strip. But the 3-bytes per pixel is constant, no matter how you divide them up.

computersarecool
 
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Re: Maximum NeoPixels Driven by one pin?

Post by computersarecool »

And the most probable way to get more RAM is to get another microcontroller?

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adafruit_support_bill
 
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Re: Maximum NeoPixels Driven by one pin?

Post by adafruit_support_bill »

Yes. The UNO has 2K, Leonardo has 2.5K and the Mega has 8K. Others like the Teensy 3.1 have enough memory to drive thousands if needed: https://www.pjrc.com/teensy/td_libs_OctoWS2811.html

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