text: # Let's Shake Hands!
  # 2018-07-24
  # Copyright (c) Cen XIN
  
  import serial
  
  ser = serial.Serial('/dev/ttyS0', 9600, timeout=1)
  
  ser.write('a'.encode('utf-8'))
  
  try:
      while 1:
          response = ser.readline()
          answer = response.decode('utf-8')
          if answer == 'b':
              print(answer)
              ser.write('b'.encode('utf-8'))
              print('Arduino Online')
              break
          else:
              print(answer)
  
  except KeyboardInterrupt:
      ser.close()
  