Added octoprint documentation (#448)

source/_components/binary_sensor.octoprint.markdown

@@ -0,0 +1,33 @@
+---
+layout: page
+title: "OctoPrint Binary Sensor"
+description: "Instructions how to integrate OctoPrint binary sensors within Home Assistant."
+date: 2016-05-05 08:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: octoprint.png
+ha_category: Binary Sensor
+---
+
+
+The `OctoPrint` binary sensor platform let you monitor if your 3D printer is printing or if there was a printing error.
+
+To set it up, add the following information to your `configuration.yaml` file:
+
+```yaml
+binary_sensor:
+  platform: octoprint
+  monitored_conditions:
+    - Printing
+    - Printing Error
+```
+
+Configuration variables:
+
+- **monitored_conditions** array (*Required*): States to monitor.
+  - Printing
+  - Printing Error
+
+<p class='note'>You must have the [OctoPrint component](/components/octoprint/) configured to use this sensor.</p>