title: Python-taking a picture with raspberry pi camera
body: <p>I have written this code to take a picture when it detects motion however when I run the code it prints 'picture taken' but does not save the picture.
  I know my camera works as I tested it in LX terminal with the raspistill command. I have also tried changing the path for the file to be saved.
  If you can see where i have been going wrong an answer would be greatly appreciated.
  Thanks</p>
  
  <pre><code>import RPi.GPIO as GPIO
  import time
  import picamera
  
  
  
  GPIO.setmode(GPIO.BCM)
  GPIO.setup(4, GPIO.IN, GPIO.PUD_DOWN)
  
  cam = picamera.PiCamera()
  time.sleep(1)
  if GPIO.input(4):
      cam.capture('/home/pi/Eaglecam/surveillance.jpg')
  print('picture taken')
  </code></pre>