Feather and Neopixel

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niophys
 
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Feather and Neopixel

Post by niophys »

Hi!
What's the best way to drive some Neopixel from a Feather board, it seems like there is no 5V voltage supply from the board, and the logic is 3.3v.
Boost converter + logic level converter?
Or is there any Feather 5v version in the pipe?

Thanks!

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adafruit_support_mike
 
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Re: Feather and Neopixel

Post by adafruit_support_mike »

The techniques are pretty much the same as for the Flora.

Our NeoPixels can run from a 3.7v LiPo or a 3-pack of AA cells. In both cases, the ATmega32u4's 3.3v logic signals are high enough for the pixels to understand, and you don't have to worry about any reverse leakage from the NeoPixel strip to the GPIO pin.

If you want to use 5v power (which works better for long strips), you can use a 5v buffer like the 74HCT125 of 74HCT245 for level shifting.

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frickeln
 
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Re: Feather and Neopixel

Post by frickeln »

Hello !

Is it save to get the power for neopixels via the "USB" Pin on the feather-board ?

How much current can be drawn via this, assuming that the powersupply connected to the micro usb jack is strong enough ?

Thanks !

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adafruit_support_mike
 
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Re: Feather and Neopixel

Post by adafruit_support_mike »

You can power NeoPixels from the USB pin, but they might not recognize the 3.3v signals coming from the Feather's output pin. You'd want to use a level shifter for that.

The traces on the PCB aren't designed to carry a lot of power, so I'd say you shouldn't try to send more than 500mA through the USB pin.

Haunted_Pliers
 
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Re: Feather and Neopixel

Post by Haunted_Pliers »

Hi,

I'm trying to get the 'neopixel_picker' example working from the 'Adafruit BluefruitLE nRF51' library, but can't seem to get the neopixels to light, though I can confirm the color data is being received via the Arduino Serial Monitor when connected to USB.

I have a 8 pixel stick (https://www.adafruit.com/products/1426) that I've connected to pin5 (default in the sketch) and changed NUMPIXELS to 8.

I've tried powering from the 3V pin when connected to USB and 3V or Bat when connected to a battery, but am having no luck getting the pixels to light. Any idea what I may be missing?

Thanks,

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Haunted_Pliers
 
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Re: Feather and Neopixel

Post by Haunted_Pliers »

So I studied the picture of the neopixel demo on the product page (https://learn.adafruit.com/system/guide ... 1448381273) and it seemed that the neopixels were connected to pin 11, not 5. I changed that in the software, moved the wire and it works now.

You guys may want to update your library!

Still doesn't work when on battery power though.

In fact I made the LED on pin 13 light up when the device enters void loop(void), after the serial connects. It never seems to reach that stage when on battery power :-/

Haunted_Pliers
 
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Joined: Mon Oct 13, 2014 10:46 am

Re: Feather and Neopixel

Post by Haunted_Pliers »

So the example 'feather_bluefruit_neopixel_animation_controller works on both battery and USB power. Here it is if anyone needs it:

https://learn.adafruit.com/ble-feather-lamp/software

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schizobovine
 
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Re: Feather and Neopixel

Post by schizobovine »

Are you initializing the serial library on startup? I was having this same problem (not running on battery power) until I realized I'd left it in debug mode, which for my code was doing:

Code: Select all

Serial.begin(9600);
while (!Serial)
    ;
...which, since it wasn't connected to my computer, was causing it to hang waiting for someone to pick up. Oops. >_>

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