Minor clean-up

Expand gitignore to include the usual py developing stuff, add an
__init__ to make this a legitimate package, move GPIO initialization
into the package init, import all stuff from input and output devices in
the package to enable the access demonstrated in the example, remove a
duplicate method from LightSensor, and make motion_detected a property
(for consistency with is_active which it presumably parallels).

gpio_components/__init__.py

@@ -0,0 +1,20 @@
+from RPi import GPIO
+
+GPIO.setmode(GPIO.BCM)
+GPIO.setwarnings(False)
+
+from .input_devices import (
+    InputDeviceError,
+    InputDevice,
+    Button,
+    MotionSensor,
+    LightSensor,
+    TemperatureSensor,
+    )
+from .output_devices import (
+    OutputDevice,
+    LED,
+    Buzzer,
+    Motor,
+    )
+

gpio_components/input_devices.py

@@ -2,10 +2,6 @@ from RPi import GPIO
 from w1thermsensor import W1ThermSensor
 
 
-GPIO.setmode(GPIO.BCM)
-GPIO.setwarnings(False)
-
-
 class InputDevice(object):
     def __init__(self, pin=None):
         if pin is None:
@@ -42,8 +38,9 @@ class Button(InputDevice):
 class MotionSensor(InputDevice):
     def _is_active_with_pause(self):
         sleep(0.1)
-        return self.is_active()
+        return self.is_active
 
+    @property
     def motion_detected(self):
         n = 20
         return sum(self._is_active_with_pause() for i in range(n)) > n/2
@@ -86,11 +83,6 @@ class LightSensor(object):
         average_value = sum(values) / len(values)
         return average_value
 
-    def _get_average_light_level(self, num):
-        values = [self._get_light_level() for n in range(num)]
-        average_value = sum(values) / len(values)
-        return average_value
-
 
 class TemperatureSensor(W1ThermSensor):
     @property

gpio_components/output_devices.py

@@ -1,10 +1,6 @@
 from RPi import GPIO
 
 
-GPIO.setmode(GPIO.BCM)
-GPIO.setwarnings(False)
-
-
 class OutputDevice(object):
     def __init__(self, pin):
         self.pin = pin