Alert Arduino via serial port when an event happens on the host computer.

ardu_alert.py

"""
ardu_alert.py

Alert Arduino via serial port when an event happens on the host computer.

Author: Mahesh Venkitachalam
Website: electronut.in

"""

import sys, serial
import time
import argparse

# main() function
def main():

  print 'starting ardu_alert...'

  # create parser
  parser = argparse.ArgumentParser(description="ardu_alert...")
  # add expected arguments
  parser.add_argument('--port', dest='strPort', required=True)

  # parse args
  args = parser.parse_args()
  
  # open serial port
  ser = serial.Serial(args.strPort, 9600)

  # loop 
  while True:
      try:
          strData = ""
          # read 
          try:
              # open file
              f = open('status.txt')
              # read line, strip whitespace, convert to upper case
              val = f.readline().strip().upper()
              # prepare serial data
              if val == 'OK':
                  strData = "1"
              else:
                  strData = "0"
              # close file
              f.close()
          except:
              print 'Could not open status.txt'
              
          # send data to Arduino
          ser.write(strData)
          ser.flush()

          # wait for 2 seconds
          time.sleep(2)
          
      except KeyboardInterrupt:
          print 'Exiting!'
          # turn off leds
          ser.write("2")
          # close serial
          ser.flush()
          ser.close()
          break


# call main
if __name__ == '__main__':
  main()