Raspberry Pi PIR motion sensor and camera script dies after loop

Question

I have a simple code for PIR sensor to detect a movement, which works as expected. Code:

from gpiozero import MotionSensor
import time
pir = MotionSensor(4)
while True:
 pir.wait_for_motion()
 print("You moved")
 pir.wait_for_no_motion()

Now when I want to use it with my camera, what happens is it works the first time, if a movement is presented it will take a picture and loops around, but after the second movement it crashes each time. Code:

from gpiozero import MotionSensor
from picamera import PiCamera
import time
pir = MotionSensor(4)
while True:
 pir.wait_for_motion()
 camera = PiCamera()
 camera.rotation = 180
 camera.start_preview(fullscreen=False, window = (50, 25, 640, 480))
 print("You moved")
 time.sleep(1)
 camera.capture('/home/pi/Desktop/image.jpg')
 #camera.stop_preview()
 pir.wait_for_no_motion()

And this is the dump of the error message:

pi@raspberrypi:~/Desktop $ python test.py 
You moved
mmal: mmal_vc_port_enable: failed to enable port vc.null_sink:in:0(OPQV): ENOSPC
mmal: mmal_port_enable: failed to enable connected port (vc.null_sink:in:0(OPQV))0x88c990 (ENOSPC)
mmal: mmal_connection_enable: output port couldn't be enabled
Traceback (most recent call last):
 File "test.py", line 10, in <module>
 camera = PiCamera()
 File "/usr/lib/python2.7/dist-packages/picamera/camera.py", line 433, in __init__
 self._init_preview()
 File "/usr/lib/python2.7/dist-packages/picamera/camera.py", line 513, in _init_preview
 self, self._camera.outputs[self.CAMERA_PREVIEW_PORT])
 File "/usr/lib/python2.7/dist-packages/picamera/renderers.py", line 558, in __init__
 self.renderer.inputs[0].connect(source).enable()
 File "/usr/lib/python2.7/dist-packages/picamera/mmalobj.py", line 2212, in enable
 prefix="Failed to enable connection")
 File "/usr/lib/python2.7/dist-packages/picamera/exc.py", line 184, in mmal_check
 raise PiCameraMMALError(status, prefix)
picamera.exc.PiCameraMMALError: Failed to enable connection: Out of resources

Answer 1

You should move the camera initialisation stuff outside the while loop.

from gpiozero import MotionSensor 
from picamera import PiCamera 
import time
pir = MotionSensor(4)
camera = PiCamera()
camera.rotation = 180
camera.start_preview(fullscreen=False, window = (50, 25, 640, 480))
while True:
 pir.wait_for_motion()
 print("You moved")
 time.sleep(1)
 camera.capture('/home/pi/Desktop/image.jpg')
 #camera.stop_preview() 
 pir.wait_for_no_motion()

That should solve your issue in my opinion.