Add ping binary sensor docs (home-assistant#2410)

source/_components/binary_sensor.ping.markdown

@@ -0,0 +1,43 @@
+---
+layout: page
+title: "Ping (ICMP) Binary sensor"
+description: "Instructions how to integrate Ping (ICMP)-based binary sensors into Home Assistant."
+date: 2017-04-11 08:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: home-assistant.png
+ha_category: Binary sensor
+ha_release: 0.43
+---
+
+
+The `ping` binary sensor platform allows you to using `ping` to send ICMP echo requests. This way you can check if a given host is online and determine the round trip times from your Home Assistant instance to that system.
+
+To use this sensor in your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+binary_sensor:
+  - platform: ping
+    host: 192.168.0.1
+```
+
+Configuration variables:
+
+- **host** (*Required*): The IP address or hostname of the system you want to track.
+- **count** (*Optional*): Number of packets to send. Defaults to 5.
+- **name** (*Optional*): Let you overwrite the name of the device. Defaults to `Ping Binary sensor`.
+
+The sensor exposes the different round trip times values measured by `ping` as attributes: 
+
+- `round trip time mdev`
+- `round trip time avg`
+- `round trip time min`
+- `round trip time max`
+
+<p class='note'>
+This sensor was only tested on a Linux-based system. 
+</p>
+