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Fadecandy + Neopixels: Fade around 0—10 flickering
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Fadecandy + Neopixels: Fade around 0—10 flickering

by Hansipete on Wed Apr 27, 2016 2:59 pm

Hi there,

for a LED project that reacts to a person approaching I'd like to have a smooth transition from OFF to the lowest brightness. The output color needs be white and so I started the project off Neopixel RGBW strips. I realised soon that the W staircasing from Off to 1 is too large. So I switched over to FadeCandy and Neopixel RGB strip, hoping that dithering will solve that issue automagically.

It seems that dithering is working, but heavily perceptible to the human eye. The specs mention something around 400fps, but it looks more like 20fps.

I followed the Adafruit FadeCandy Guide, have my server running on OSX with no special configuration file. Tested with 5 LEDs only. Python code to drive looks like this:
Code: Select all | TOGGLE FULL SIZE
#!/usr/bin/env python
import opc, time
from itertools import cycle

numLEDs = 5
client = opc.Client('localhost:7890')

black = [ (0,0,0) ] * numLEDs
white = [ (1,1,1) ] * numLEDs

# Fade to white
client.put_pixels(black)
client.put_pixels(black)
time.sleep(0.5)

d = 0.50
m = 10
it = cycle(range(0, m) + range(m, 0, -1))

try:
   while True:
      for v in it:
         client.put_pixels([ (v,v,v) ] * numLEDs)
         print v
         time.sleep(d)
except:
   client.put_pixels(black)
   client.put_pixels(black)


Is this standard behaviour? Or do I miss something essential? I think so... :-) Any hint in the right direction is appreciated. Thank youu!

Have a good day,
Hansipete

Hansipete
 
Posts: 36
Joined: Tue Aug 12, 2014 10:39 am

Re: Fadecandy + Neopixels: Fade around 0—10 flickering

by gwolf on Sun Jan 07, 2018 12:51 pm

Hi Hansipete :-)

I see the same fade issue on low brightness, while working on an adaptive NeoPixel RGBW lamp. Did you find a solution for fade in that is both smooth and flicker free?

Best from Berlin,
Gabriel

gwolf
 
Posts: 1
Joined: Sun Jan 07, 2018 12:37 pm

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