NeoPixel power
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NeoPixel power

by gaijinpunch on Tue Sep 03, 2013 8:46 pm

Howdy

Reading another thread, I've learned that the smartest way to power a NeoPixel strip via battery is one of these 5V USB battery jobs. Fair enough. However, I'm curious as to what I can expect performance wise. I've got one project in mind which will be "about a 1m strip" give or take, and would like to use the 60 LEDs per strip version. A more ambitious one will use about 2m on 2 sides of an object (total of 4m). Something tells me I'm going to need the 30 LEDs per strip iteration on that one, due to power. There's a chance I can cut it down to 2m x 1, but I have to think about how to mount it and whatnot. This is an update to a successful LDP8806 project, where the signal was split right off the breakout board and mirrored on either side. It was a bit of a hassle though, to be honest.

Anywho, I'm unedcuated when it comes to currents, but am not afraid to read, if anyone wants to point me to a nice primer. :)
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Re: NeoPixel power

by EternalCore on Tue Sep 03, 2013 10:56 pm

In all honesty it all depends on what you are going to use them for, to be able to chose a power supply for it; which includes the size of power storage in, for wall Amps and for battery Amp/hour(AH/mAh).
Things I've Made Here:
1.[101-Help]~12v -> 5v 1.5A Regulated Power For NeoPixels.: http://goo.gl/uMXuk7
2.[Example]NeoPixel Strip Scrolling Cylon Eye!: http://goo.gl/4RzWQQ
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Re: NeoPixel power

by adafruit_support_bill on Wed Sep 04, 2013 4:55 am

If you are not driving them too hard (not too many pixels lit at a time), you can get by with surprisingly little power compared to the worst-case (all pixels full-brightness white). The general rule-of-thumb is that each pixel draws as much as 60mA (20 each for the R, G and B). Worst case current draw is roughly 60 x the number of pixels.

For 30 pixels, that would be 1800mA. If you have a 3600mAh battery, it will drive your strip at full brightness for 2 hours (3600 / 1800 = 2)

That is a 'worst case' calculation. Typical display patterns tend to use substantially less current.
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Re: NeoPixel power

by gaijinpunch on Wed Sep 04, 2013 6:38 pm

Thanks... that gives me at least a rough idea. I'd have to bust out the calculator to figure out what's going to happen realistically. Not sure if my 2m x 2 design is even practical, but the 1 meter strip is. I think I can at least order some strips and play around though.

Does the library offered by Adafruit give the ability to lower the brightness for longer battery life?

A couple of side question: If I order 2 meters worth, are they connected, or do they come in 1 meter strips? And are the the solderless strip clips compatible? It looks like the NeoPixel in the picture, but no mention of it.
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Re: NeoPixel power

by adafruit_support_bill on Wed Sep 04, 2013 6:43 pm

Does the library offered by Adafruit give the ability to lower the brightness for longer battery life?

Yes. You can set the color and intensity of each pixel individually.
If I order 2 meters worth, are they connected,

Yes. You will get a 2 meter section cut from a 5 meter spool.
And are the the solderless strip clips compatible?

No. These only work with our analog strips.
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