S、RotationSensor

import time
import RPi.GPIO as GPIO
 
 
GPIO.setmode(GPIO.BOARD)
 
SIA = 3
SIB= 5
SW = 7
 
GPIO.setup(SW,GPIO.IN)
GPIO.setup(SIA,GPIO.IN)
GPIO.setup(SIB,GPIO.IN)
flag = 0
resetflag = 0
globalCount = 0
while 1:
        lastSib = GPIO.input(SIB)
        while not GPIO.input(SW):
                resetflag = 1
        while not GPIO.input(SIA):
                currentSib = GPIO.input(SIB)
                flag =1
        if resetflag:
                        globalCount = 0
                        resetflag = 0
                        print('Count reset')
                        continue
        if flag:
                if lastSib == 0 and currentSib == 1:
                        print('right rotate')
                        globalCount += 1
                if lastSib == 1 and currentSib ==0:
                        print('left rotate')
                        globalCount -=1
                flag =0
                print('current = %s' % globalCount)