Neopixel power

EL Wire/Tape/Panels, LEDs, pixels and strips, LCDs and TFTs, etc products from Adafruit

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philg
 
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Joined: Sun Mar 06, 2011 4:42 pm

Neopixel power

Post by philg »

I just received a 5 m roll of neopixels. Can't wait to see them glow. Before I power them up, I just want to check on the power supply polarity and data color codes. Unlike the picture, the two bare power leads are RED and WHITE. I always assume RED is positive but before smoking 150 LEDs I thought I should check. Also want to confirm the colors of the signals on the 3 position connector. There are RED, GREEN, and WHITE wires. I assume GREEN is data and WHITE is GND. Do I have that correct?

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pburgess
 
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Re: Neopixel power

Post by pburgess »

That sounds correct. If you want to double-check, look closely where the wires connect to the strip; there will be labels for DIN (data in), +5V and GND.

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philg
 
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Re: Neopixel power

Post by philg »

Ok, its all connected properly. I used a 330 ohm resistor in series with the D6 line. However no joy. The supply is 5.2VDC at the strip but the data line data is only 2v peak at the strip data input. It is 4.2v peak at the output of the nano before the 330 ohm resistor. If that is supposed to be a series termination it seems too big.

I tried shorting the 330 ohm resistor and the signal at the strip input is now more than 4v peak but still no lights.

The strip is a PN 1376 and yes I am connected to the data input end of the strip (beginning of the reel). The data shows at 800kHz on the scope. After a long while the first LED (0) is flickering but none of the others are lit. Running strandtest with just the number of pixels changed to 150.

I disconnected the nano, then turned off the 5v supply then cycled them back on an it works! Still have the jumper across the 330 ohm resistor.

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