add rpi_gpio sensor page

source/components/sensor.rpi_gpio.markdown

@@ -0,0 +1,34 @@
+---
+layout: page
+title: "Raspberry PI GPIO sensor support"
+description: "Instructions how to integrate the GPIO sensor capability of a Raspberry PI into Home Assistant."
+date: 2015-08-30 19:00
+sidebar: false
+comments: false
+sharing: true
+footer: true
+---
+
+<img src='/images/supported_brands/raspberry-pi.png' class='brand pull-right' />
+The rpi_gpio sensor platform allows you to read sensor values of the GPIOs of your [Raspberry Pi](https://www.raspberrypi.org/).
+
+To use your Raspberry Pi's GPIO in your installation, add the following to your `configuration.yaml` file:
+
+```
+# Example configuration.yaml entry
+sensor:
+  platform: rpi_gpio
+  pull_mode: "UP"
+  value_high: "Active"
+  value_low: "Inactive"
+  ports:
+    11: PIR Office
+    12: PIR Bedroom
+```
+
+For more details about the GPIO layout, visit the Wikipedia [article](https://en.wikipedia.org/wiki/Raspberry_Pi#GPIO_connector) about the Raspberry Pi.
+
+<p class='note warning'>
+As this requires access to the GPIO, you will need to run Home Assistant as root.
+</p>
+