树莓派+RGB彩灯实现跑马灯

RGB彩灯跟普通的LED不同，它可以根据RGB的色值自定义颜色，从而轻松的实现跑马灯的效果，我们选用HW-478 3色全彩LED smd模块来实现。

一、硬件接线
RGB彩灯硬件接线比较简单，负极接GND，R/G/B分别接树莓派定义的针脚即可。

二、软件实现：

import RPi.GPIO
import time

R,G,B = 18,15,14

RPi.GPIO.setmode(RPi.GPIO.BCM)

RPi.GPIO.setup(R,RPi.GPIO.OUT)
RPi.GPIO.setup(G,RPi.GPIO.OUT)
RPi.GPIO.setup(B,RPi.GPIO.OUT)

pwmR = RPi.GPIO.PWM(R,50)
pwmG = RPi.GPIO.PWM(G,50)
pwmB = RPi.GPIO.PWM(B,50)

pwmR.start(0)
pwmG.start(0)
pwmB.start(0)

t = 1
#no light on 
pwmR.ChangeDutyCycle(0)
pwmG.ChangeDutyCycle(0)
pwmB.ChangeDutyCycle(0)
time.sleep(t)

try:
    while(True):
        pwmR.ChangeDutyCycle(100)
        pwmG.ChangeDutyCycle(0)
        pwmB.ChangeDutyCycle(0)
        time.sleep(t)
        
        pwmR.ChangeDutyCycle(0)
        pwmG.ChangeDutyCycle(100)
        pwmB.ChangeDutyCycle(0)
        time.sleep(t)
        
        pwmR.ChangeDutyCycle(0)
        pwmG.ChangeDutyCycle(0)
        pwmB.ChangeDutyCycle(100)
        time.sleep(t)
        
        pwmR.ChangeDutyCycle(100)
        pwmG.ChangeDutyCycle(100)
        pwmB.ChangeDutyCycle(0)
        time.sleep(t)
        
        pwmR.ChangeDutyCycle(100)
        pwmG.ChangeDutyCycle(0)
        pwmB.ChangeDutyCycle(100)
        time.sleep(t)
        
        pwmR.ChangeDutyCycle(0)
        pwmG.ChangeDutyCycle(100)
        pwmB.ChangeDutyCycle(100)
        time.sleep(t)
        
        pwmR.ChangeDutyCycle(100)
        pwmG.ChangeDutyCycle(100)
        pwmB.ChangeDutyCycle(100)
        time.sleep(t)
        
        pwmR.ChangeDutyCycle(0)
        pwmG.ChangeDutyCycle(0)
        pwmB.ChangeDutyCycle(0)
        time.sleep(t)
        
except keyboardInterrupt:
    pass

pwmR.stop()
pwmG.stop()
pwmB.stop()

RPi.GPIO.cleanup()
        

参考资料：
https://shumeipai.nxez.com/2014/11/13/rpi-gpio-module-pwm-basic-function.html