neoPixel | Technology Tutorials

In this video lesson we show how neopixels work at a fundamental level, and show how you can use the Raspberry Pi Pico State Machines to control the neoixels. Neopixels are an excellent example for showing the importance of the pico state machine. The neopixels demand precise timing and sequence of bits to operate properly, and that precision can not be achieved in python. The video explains how the State Machines can be programmed to control the neopixels.

For your convenience, the code is included below.

import rp2
from machine import Pin
import time
@rp2.asm_pio(sideset_init=rp2.PIO.OUT_HIGH,
             out_shiftdir=rp2.PIO.SHIFT_LEFT,
             autopull=True,
             pull_thresh=24)
def ws2812():
    wrap_target()
    label("bitloop")
    out(x,1).side(0)
    jmp(not_x,"do_zero").side(1)
    nop().side(1)[5-1]
    nop().side(0)[2-1]
    jmp("bitloop").side(0)
    label("do_zero")
    nop().side(1)[2-1]
    jmp("bitloop").side(0)[6-1]
    wrap()
sm=rp2.StateMachine(0,ws2812,freq=8000000,sideset_base=Pin(0))
sm.active(1)

def write_neopixel(colors):
    for color in colors:
        grb=color[1]<<16 | color[0]<<8 | color[2]
        sm.put(grb,8)
        
    
NUM_LEDS =8
myColor=[0]*NUM_LEDS
myColor=[[100,0,0],
         [0,100,0],
         [0,0,100],
         [0,100,100],
         [100,0,100],
         [100,100,0],
         [200,100,0],
         [255,255,255]]
write_neopixel(myColor)

import rp2

from machine import Pin

import time

@rp2.asm_pio(sideset_init=rp2.PIO.OUT_HIGH,

out_shiftdir=rp2.PIO.SHIFT_LEFT,

autopull=True,

pull_thresh=24)

def ws2812():

wrap_target()

label("bitloop")

out(x,1).side(0)

jmp(not_x,"do_zero").side(1)

nop().side(1)[5-1]

nop().side(0)[2-1]

jmp("bitloop").side(0)

label("do_zero")

nop().side(1)[2-1]

jmp("bitloop").side(0)[6-1]

wrap()

sm=rp2.StateMachine(0,ws2812,freq=8000000,sideset_base=Pin(0))

sm.active(1)

def write_neopixel(colors):

for color in colors:

grb=color[1]<<16 | color[0]<<8 | color[2]

sm.put(grb,8)

NUM_LEDS =8

myColor=[0]*NUM_LEDS

myColor=[[100,0,0],

[0,100,0],

[0,0,100],

[0,100,100],

[100,0,100],

[100,100,0],

[200,100,0],

[255,255,255]]

write_neopixel(myColor)

In this lesson we show how we can control the neoPixel array using an Infrared IR Remote Control on the Raspberry Pi Pico W in micropython. The video above explains things step-by-step. For your convenience, the code is included below. Enjoy!

import neopixel
from machine import Pin
import time

pixPin = 0
pixSize = 8
pix = neopixel.NeoPixel(Pin(pixPin), pixSize)

def getRGB(deg):
    m=1/60
    if deg>=0 and deg<60:
        R=1
        G=0
        B=m*deg
    if deg>=60 and deg<120:
        R=1-m*(deg-60)
        G=0
        B=1
    if deg>=120 and deg<180:
        R=0
        G=m*(deg-120)
        B=1
    if deg>=180 and deg<240:
        R=0
        G=1
        B=1-m*(deg-180)
    if deg>=240 and deg<300:
        R=m*(deg-240)
        G=1
        B=0
    if deg>=300 and deg<360:
        R=1
        G=1-m*(deg-300)
        B=0
    myColor=(int(R*255),int(G*255),int(B*255))
    return myColor

from ir_rx.print_error import print_error
from ir_rx.nec import NEC_8
import SERVO
IRdict ={69 : 'POWER', 70: 'MODE',71 : 'OFF',
         68: 'PLAY', 64 : 'BACK', 67 : 'FORWARD', 7: 'ENTER', 21: '-',
         9 : '+', 22 : 0,25 : 'LOOP', 13:'USD' ,
         12: 1, 24 : 2,94 : 3,
        8 :4, 28 : 5, 90 : 6,
        66 : 7, 82 : 8, 74 : 9}

newCommand=[]
beginRecord=False
cmdReady=False
angleString=''
newBit=""
irPin=17
cmd=0
myIR = Pin(irPin, Pin.IN)
def callback(IRbit, addr, ctrl):
    global newCommand
    global beginRecord
    global cmdReady
    global IRdict
    global cmd
    if IRbit==69:
        beginRecord=True
        newCommand=[]
        cmdReady=False
    if beginRecord==True and IRbit!=-1:
        newCommand.append(IRdict[IRbit])
    if IRbit==7:
        cmdReady=True
        cmd=newCommand[1]
        
IR = NEC_8(myIR, callback)  # Instantiate receiver
try:
    while True:
        if cmd==0:
            for i in range(0,8):
                pix[i]=[0,0,0]
            pix.write()
        if cmd==1:
            pix.fill([255,0,0])
            pix.write()
        if cmd==2:
            pix.fill([0,255,0])
            pix.write()
        if cmd==3:
            pix.fill([0,0,255])
            pix.write() 
        if cmd==4:
            for i in range(0,360,1):
                for j in range(0,8,1):
                    deg=i+(j)*45
                    if deg>=360:
                        deg=deg-360
                    color=getRGB(deg)
                    pix[j]=color
                    if cmd!=4:
                        break
                if cmd!=4:
                    break
                pix.write()
                time.sleep(.01)
        if cmd==5:
            for i in range(0,360,1):
                color=getRGB(i)
                pix.fill(color)
                pix.write()
                time.sleep(.01)
                if cmd!=5:
                    break
        if cmd==6:
            for i in range(1,8,1):
                pix.fill([255,0,0])
                pix[i]=[0,0,255]
                #pix[7-i]=green
                pix.write()
                time.sleep(.1)
                if cmd!=6:
                    break
            for i in range(6,-1,-1):
                pix.fill([255,0,0])
                pix[i]=[0,0,255]
                #pix[7-i]=green
                pix.write()
                time.sleep(.1)
                if cmd!=6:
                    break

except KeyboardInterrupt:
    IR.close()
    for i in range(0,8):
        pix[i]=[0,0,0]
        pix.write()
    print("Program Terminated")

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import neopixel

from machine import Pin

import time

pixPin = 0

pixSize = 8

pix = neopixel.NeoPixel(Pin(pixPin), pixSize)

def getRGB(deg):

m=1/60

if deg>=0 and deg<60:

R=1

G=0

B=m*deg

if deg>=60 and deg<120:

R=1-m*(deg-60)

G=0

B=1

if deg>=120 and deg<180:

R=0

G=m*(deg-120)

B=1

if deg>=180 and deg<240:

R=0

G=1

B=1-m*(deg-180)

if deg>=240 and deg<300:

R=m*(deg-240)

G=1

B=0

if deg>=300 and deg<360:

R=1

G=1-m*(deg-300)

B=0

myColor=(int(R*255),int(G*255),int(B*255))

return myColor

from ir_rx.print_error import print_error

from ir_rx.nec import NEC_8

import SERVO

IRdict ={69 : 'POWER', 70: 'MODE',71 : 'OFF',

68: 'PLAY', 64 : 'BACK', 67 : 'FORWARD', 7: 'ENTER', 21: '-',

9 : '+', 22 : 0,25 : 'LOOP', 13:'USD' ,

12: 1, 24 : 2,94 : 3,

8 :4, 28 : 5, 90 : 6,

66 : 7, 82 : 8, 74 : 9}

newCommand=[]

beginRecord=False

cmdReady=False

angleString=''

newBit=""

irPin=17

cmd=0

myIR = Pin(irPin, Pin.IN)

def callback(IRbit, addr, ctrl):

global newCommand

global beginRecord

global cmdReady

global IRdict

global cmd

if IRbit==69:

beginRecord=True

newCommand=[]

cmdReady=False

if beginRecord==True and IRbit!=-1:

newCommand.append(IRdict[IRbit])

if IRbit==7:

cmdReady=True

cmd=newCommand[1]

IR = NEC_8(myIR, callback) # Instantiate receiver

try:

while True:

if cmd==0:

for i in range(0,8):

pix[i]=[0,0,0]

pix.write()

if cmd==1:

pix.fill([255,0,0])

pix.write()

if cmd==2:

pix.fill([0,255,0])

pix.write()

if cmd==3:

pix.fill([0,0,255])

pix.write()

if cmd==4:

for i in range(0,360,1):

for j in range(0,8,1):

deg=i+(j)*45

if deg>=360:

deg=deg-360

color=getRGB(deg)

pix[j]=color

if cmd!=4:

break

if cmd!=4:

break

pix.write()

time.sleep(.01)

if cmd==5:

for i in range(0,360,1):

color=getRGB(i)

pix.fill(color)

pix.write()

time.sleep(.01)

if cmd!=5:

break

if cmd==6:

for i in range(1,8,1):

pix.fill([255,0,0])

pix[i]=[0,0,255]

#pix[7-i]=green

pix.write()

time.sleep(.1)

if cmd!=6:

break

for i in range(6,-1,-1):

pix.fill([255,0,0])

pix[i]=[0,0,255]

#pix[7-i]=green

pix.write()

time.sleep(.1)

if cmd!=6:

break

except KeyboardInterrupt:

IR.close()

for i in range(0,8):

pix[i]=[0,0,0]

pix.write()

print("Program Terminated")

Technology Tutorials

Tag Archives: neoPixel

Controlling NeoPixel Array on PIO State Machine on Raspberry Pi Pico

Control NeoPixel Array With Infrared IR Remote Control on Raspberry Pi Pico in MicroPython

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