LED Ring NeoPixel

Description

The NeoPixel ring has 3 connections: GND, +/VCC, and the signal/IN. The signal is connected to an output pin and given as parameter (in the example pin 0). The chip to decode the protocol - built into the NeoPixel ring - is WS2812. They are also available in different sizes (more or less LEDs) and different shapes (e.g. band). You have to provide the total number of LEDs as parameter.

If you need more than one ring (or other arrangements), you can put them in a row - basically connecting the next ring to the first one (you have to solder it on).

How to connect it electrically

You can "chain" them. If you only have one ring, just connect GND, VCC, and In.

How to control it in MicroPython

 1 import neopixel
 2 from machine import Pin
 3 
 4 # number of leds
 5 n=8
 6 # connected Pin
 7 p=0
 8 
 9 np = neopixel.NeoPixel(Pin(p),n)
10 
11 # sets color of the led at position 0 to (r,g,b)
12 np[0] = (255,0,0)
13 # colors the leds
14 np.write()

A small Program in MicroPython

 1 import neopixel
 2 from machine import Pin
 3 from time import sleep
 4 
 5 # number of leds
 6 n=8
 7 # connected Pin
 8 p=0
 9 
10 np = neopixel.NeoPixel(Pin(p),n)
11 
12 # colors the led at position in (r,g,b)
13 def color(position, r,g,b):
14   np[position]=(r,g,b)
15   np.write()
16 
17 # remove all colors
18 def clearAll():
19   for i in range(n):
20     color(i,0,0,0)
21 
22 # remove color from led at position
23 def clear(position):
24   color(position,0,0,0)
25 
26 
27 # the color (r,g,b) should run x times like a cycle 
28 def cycle(r,g,b,wait,x): 
29   # before setting new colors, clear the ring
30   clearAll()
31   
32   # the cycle should run x times
33   for j in range(x):
34     for i in range(n):
35       # clear the previous led
36       if(i==0):
37         clear(n-1)
38       else:
39         clear(i-1)
40       
41       # color the current led
42       color(i,r,g,b)
43       
44       # wait, color is displayed this time
45       sleep(wait)
46 
47 
48 cycle(0,255,255,0.5,4)

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