Controlling neopixel power draw using setBrighness()

[jolleon]

Hello! I just received my first circuit playground and strand of neopixel and am very excited to use it in a costume!

I'm planning to use the full 4m strand of 60 led/m RGB neopixels (got the skinny one), and trying to figure power requirements. As it will be wearable I'm interested in not having to lug around huge batteries.

With my 4*60 = 240 LEDs, following the 20mA guideline that would be ~5A, which is quite a lot. As I don't need the full brightness (from my tests it seems like I could go as low as setBrightness(10-20)!), I'm wondering whether I could rely on setBrightness to cap power need.

Is there a linear correlation between the brightness set and power draw?

For instance if I do setBrightness(50) (i.e. 1/5 brightness) at the beginning of my sketch and leave it there, can I assume total power draw will be 1/5 and therefore plan for 1A of power use for my 240 LEDs?

[adafruit_support_bill]

All else being equal, the power requirements are roughly proportional to the brightness level you set.

I'd recommend starting with a read through this guide for tips on efficient use of power:
https://learn.adafruit.com/sipping-power-with-neopixels

[jolleon]

That's a great article, thank you!
Looks like power use is indeed directly correlated to brightness, and all the other tricks mentioned in the guide will be helpful too.