树莓派基础实验33：TCRT5000红外循迹传感器实验

#!/usr/bin/env python
import RPi.GPIO as GPIO

TrackPin = 11
LedPin   = 12

def setup():
    GPIO.setmode(GPIO.BOARD)       # Numbers GPIOs by physical location
    GPIO.setup(LedPin, GPIO.OUT)   # Set LedPin's mode is output
    GPIO.setup(TrackPin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
    GPIO.output(LedPin, GPIO.LOW) # Set LedPin LOW to off led

def loop():
    while True:
        if GPIO.input(TrackPin) == GPIO.LOW:
            print 'White line is detected'
            GPIO.output(LedPin, GPIO.HIGH)  # led on
        else:
            print '...Black line is detected'
            GPIO.output(LedPin, GPIO.LOW) # led off

def destroy():
    GPIO.output(LedPin, GPIO.LOW)     # led off
    GPIO.cleanup()                     # Release resource

if __name__ == '__main__':     # Program start from here
    setup()
    try:
        loop()
    except KeyboardInterrupt: 
 # When 'Ctrl+C' is pressed, the child program destroy() will be  executed.
        destroy()