Neotrellis power requirements

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gruthor
 
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Joined: Mon May 03, 2021 10:21 am

Neotrellis power requirements

Post by gruthor »

I've had a 16x16 LED neotrellis installed for a while on a feather-based project, and there are some power issues that have sort of eluded me for a while; I've got a workaround, but it's not optimal and I have questions.

Historically, I had what seemed to be issues with drawing too much power for my system to handle. I expected this had to do with driving all the LEDs at full brightness, which I know from the documents on this website can draw up to 60mA * 64 LEDs = 3850mA. And, given that the feather it is drawing power on can only supply 500mA, this sounds like the source of the problem.

In the past I solved this by only using single colors at a time (r, g, b) and reducing brightness.

I do note that your website has a kit that seems to do the same thing I do. https://www.adafruit.com/product/1929?g ... 1ZEALw_wcB...

But how does this work? It seems that you're drawing power from a battery that can supply 3.7V @ 500mA. How is this enough to drive the LEDs? Or do you expect users to be careful about how they program the LEDs to not draw over the limit?

My thinking thus far, to be able to drive things more fully, would be to power my Neotrellis separately, bypassing the feather's power supply, and providing power to the trellis with a buck converter.

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dastels
 
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Re: Neotrellis power requirements

Post by dastels »

A 16x16 matrix has 4 times the number of NeoPIxels as an 8x8 (the product you link to), specifically 256 pixels. My opinion is that you'll need an external supply for that. See the NeoPixel guide https://learn.adafruit.com/adafruit-neopixel-uberguide for more advice. As a datapoint, that matrix would require over 15A if all pixels were full brightness white.

Dave

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