rgb_led.py

#! /usr/bin/python3
import time
import threading
import RPi.GPIO as GPIO

RED_PIN = 22
GREEN_PIN = 23
BLUE_PIN = 24

COLOURS = {
  "OFF":      None,
  "RED":      [RED_PIN],
  "GREEN":    [GREEN_PIN],
  "BLUE":     [BLUE_PIN],
  "CYAN":     [GREEN_PIN,  BLUE_PIN],
  "MAGENTA":  [RED_PIN,   BLUE_PIN],
  "YELLOW":   [RED_PIN,   GREEN_PIN],
  "WHITE":    [RED_PIN,   GREEN_PIN,  BLUE_PIN]
}

class RGB_LED (threading.Thread):
  def __init__(self, threadID, name):
    threading.Thread.__init__(self)
    self.threadID = threadID
    self.name = name

    # BCM pin numbering!
    GPIO.setmode(GPIO.BCM)
    GPIO.setup([RED_PIN, GREEN_PIN, BLUE_PIN], direction=GPIO.OUT, initial=GPIO.HIGH)

    self.state = 1
    self.colour_0 = "OFF"
    self.colour_1 = "OFF"
    self.colour_0_mem = None
    self.colour_1_mem = None

    self.timer = None

  def __del__(self):
    GPIO.cleanup()

  def set_static(self, colour:str=None, timeout_sec:float=None, restore_previous_on_timeout:bool=False):
    if timeout_sec:
      if self.timer:
        return

      self.timer = timeout_sec + 0.5
      if restore_previous_on_timeout:
        self.colour_0_mem = self.colour_0
        self.colour_1_mem = self.colour_1
      else:
        self.colour_0_mem = None
        self.colour_1_mem = None

    self.colour_0 = colour
    self.colour_1 = colour

    pins = COLOURS[colour]

    # All pins off (perhaps momentarily)
    GPIO.output([RED_PIN, GREEN_PIN, BLUE_PIN], GPIO.LOW)

    # Write required pins high
    if pins != None:
      GPIO.output(pins, GPIO.HIGH)

  def set_blink(self, colour_0:str=None, colour_1:str="OFF", timeout_sec:float=None, restore_previous_on_timeout:bool=False):
    if timeout_sec:
      if self.timer:
        return

      self.timer = timeout_sec + 0.5
      if restore_previous_on_timeout:
        self.colour_0_mem = self.colour_0
        self.colour_1_mem = self.colour_1
      else:
        self.colour_0_mem = None
        self.colour_1_mem = None

    self.colour_0 = colour_0
    self.colour_1 = colour_1

  def run(self):
    while True:
      if self.state == 0:
        self.state = 1
        pins = COLOURS[self.colour_1]
      else:
        self.state = 0
        pins = COLOURS[self.colour_0]

      # All pins off (perhaps momentarily)
      GPIO.output([RED_PIN, GREEN_PIN, BLUE_PIN], GPIO.LOW)

      # Write required pins high
      if pins != None:
        GPIO.output(pins, GPIO.HIGH)

      # Flash/wait period
      time.sleep(0.5)

      # Turn off the light when the timer expires
      if self.timer:
        self.timer -= 0.5

        if self.timer <= 0:
          self.timer = None
          if self.colour_0_mem:
            self.colour_0 = self.colour_0_mem;
            self.colour_0_mem = None;
          else:
            self.colour_0 = "OFF"

          if self.colour_1_mem:
            self.colour_1 = self.colour_1_mem;
            self.colour_1_mem = None;
          else:
            self.colour_1 = "OFF"

if __name__ == "__main__":
  led = RGB_LED(1, "LED")
  led.start()

  try:
    while True:
      led.set_blink("YELLOW", "BLUE")
      time.sleep(5)

      for colour in COLOURS:
        led.set_static(colour)
        time.sleep(0.5)

  except:
    GPIO.cleanup()
    exit()