NeoPixel 8-RGB strip does not behave as 8x8 array

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flounder
 
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NeoPixel 8-RGB strip does not behave as 8x8 array

Post by flounder »

I did a "proof of concept" demo of a project using the first two rows of an 8x8 NeoPixel array I happened to have in breadboard format. The lights were blinding and impressive. I then got two 8-RGB strips, moved the wires from the array to the strip, and see that the lights flash (for example), bright red as they turn on, then the intensity drops and they can be easily looked at without discomfort. The prototype is powered by a UNO, and I'm taking the +5 from the board to power the strip. The voltage is currently derived from the USB connector of the UNO, and that, from my laptop. The only thing that changed was the NeoPixels.

Why is the 8xRGB strip not nearly as bright as the first two rows of an 8x8 grid? And what could I do about it?

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adafruit_support_rick
 
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Re: NeoPixel 8-RGB strip does not behave as 8x8 array

Post by adafruit_support_rick »

But the strip starts out as bright as the matrix, and then fades? USB power should be able to handle that many pixels. It sounds like a wiring issue to me.

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flounder
 
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Re: NeoPixel 8-RGB strip does not behave as 8x8 array

Post by flounder »

But how could it be "wiring"' when all I did was pull the three wires out of three holes in the breadboard and plug them into three other holes in the same breadboard? If I had gone from prototype to final, yes, I could see that, but all I did was switch three wires. I have a 470 ohm resistor in series with the data pin of both boards, and a 1000uF capacitor across the power lines, just like with the matrix. This is why it surprises me that I don't see the same behavior.

p.s. to make a NeoPixel strip breadboard-friendly, break off four pins from a long strip of 90-degree pins and solder it to the Din side. If you have two breadboards side-by-side, you can put another set of pins on the Dout side, but on a single breadboard there is no way to get both ends to plug in.

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Re: NeoPixel 8-RGB strip does not behave as 8x8 array

Post by adafruit_support_rick »

Gee. I don't know. Maybe a breadboard problem? Can you try some different columns on the breadboard? Or plug you array into the same holes as the strip goes into? The pixels themselves are all the same. There's no way for them to be different except through programming or through a power problem.

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CIGUOLLA
 
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Re: NeoPixel 8-RGB strip does not behave as 8x8 array

Post by CIGUOLLA »

flounder wrote:But how could it be "wiring"' when all I did was pull the three wires out of three holes in the breadboard and plug them into three other holes in the same breadboard? If I had gone from prototype to final, yes, I could see that, but all I did was switch three wires. I have a 470 ohm resistor in series with the data pin of both boards, and a 1000uF capacitor across the power lines, just like with the matrix. This is why it surprises me that I don't see the same behavior.

p.s. to make a NeoPixel strip breadboard-friendly, break off four pins from a long strip of 90-degree pins and solder it to the Din side. If you have two breadboards side-by-side, you can put another set of pins on the Dout side, but on a single breadboard there is no way to get both ends to plug in.
Hola ha todos, tengo una duda, tengo un proyecto de 12 matrices de 8x8, para un tablero, pero con arduino UNO, no he sido capaz de controlar todos los pixels, alguien sabria decirme si es problema del arduino UNO que no tiene suficiente RAM, y por tanto podria anejarlo con un Arduino Mega. Siento no poder manifestar en ingles.

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Re: NeoPixel 8-RGB strip does not behave as 8x8 array

Post by adafruit_support_rick »

CIGUOLLA wrote:Hola ha todos, tengo una duda, tengo un proyecto de 12 matrices de 8x8, para un tablero, pero con arduino UNO, no he sido capaz de controlar todos los pixels, alguien sabria decirme si es problema del arduino UNO que no tiene suficiente RAM, y por tanto podria anejarlo con un Arduino Mega. Siento no poder manifestar en ingles.
You have 768 pixels. Each requires 3 bytes of RAM. That is 2304 bytes of RAM. The Uno only has 2048 bytes of RAM. An Arduino Mega has 8193 bytes of RAM. You can use a Mega.

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