water-field.py

#!/usr/bin/env python

import argparse
import RPi.GPIO as GPIO
import time

# Parse command line arguments
parser = argparse.ArgumentParser(description="Water the field.")
parser.add_argument("--minutes", dest="minutes", help="How long to water for.")
args = parser.parse_args()

print("Watering for {} minutes".format(args.minutes))

seconds = float(args.minutes) * 60
channel = 17

GPIO.setmode(GPIO.BOARD)
GPIO.setup(channel, GPIO.OUT)
GPIO.output(channel, GPIO.HIGH)

try:
    time.sleep(seconds)
except KeyboardInterrupt:
    print("Interrupted")
finally:
    GPIO.output(channel, GPIO.LOW)
    GPIO.cleanup()