Single neopixel in chain flashes brightly sporadically

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pneumatic
 
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Single neopixel in chain flashes brightly sporadically

Post by pneumatic »

Hi,

I've got 2 flora neopixels acting as eyes for my Dragon. They're being driven by a TinyPico esp32 running micropython. Sporadically, one or the other neopixels will briefly flash a bright color for a fraction of a second (probably 1 refresh cycle, which is ~50ms). Sometimes it's the first in the chain (left eye), and sometimes it's the second/last in the chain (right). It happens every few minutes.

My first guess was that the pin I was using (25) was being used for something else and occasionally getting stray signals on that pin, so I switched it to pin 33, but that hasn't fixed it. My best guess now is that it's getting electrical noise that's flipping a bit that being bit-banged in, but I'm not sure what would be causing it.

Cold solder joint? The fact that the pixels are being held in place by silly putty? (it's surprisingly useful for prototyping), or maybe the wifi signal is being picked up by the wires (though it doesn't appear to be associated with/triggered by wifi traffic).

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adafruit_support_bill
 
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Re: Single neopixel in chain flashes brightly sporadically

Post by adafruit_support_bill »

Sounds like maybe a marginal connection, or possibly some external interference.

How much wire between processor and first pixel? Between the two pixels? Any nearby sources of potential interference?

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pneumatic
 
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Re: Single neopixel in chain flashes brightly sporadically

Post by pneumatic »

about 6 inches (15cm) of wire from the TinyPico to the first pixel (mostly coiled up and stuffed into the head), and maybe 2 inches (5cm) between the pixels. The only sources of interference I can think of are the bluetooth and wifi antennas on the TinyPico itself.

I needed, I can dig the pixels out of the head and show the wiring.

Thanks for the help,
-- Mitch

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adafruit_support_bill
 
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Re: Single neopixel in chain flashes brightly sporadically

Post by adafruit_support_bill »

Doesn't sound like length would be an issue. Although the 'coiled up and stuffed' aspect could be a factor. If you stretch things out on the bench does the problem persist?

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