Add initial myStrom buttons docs (#2429)

* Add initial myStrom buttons docs

* Add details about feedback

source/_components/binary_sensor.mystrom.markdown

@@ -0,0 +1,70 @@
+---
+layout: page
+title: "myStrom Binary Sensor"
+description: "Instructions how to integrate myStrom buttons into Home Assistant."
+date: 2017-04-14 08:15
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: mystrom.png
+ha_category: Binary Sensor
+ha_iot_class: "Local Polling"
+ha_release: 0.43
+---
+
+
+The `mystrom` binary sensor platform allows you to use [myStrom Wifi Buttons](https://mystrom.ch/wifi-button/) with Home Assistant. The myStrom Wifi Buttons support three and the myStrom WiFi Button + four different push pattern:
+
+- `single`: Short push (approx. 1/2 seconds)
+- `double`: 2x sequential short pushes (within 2 seconds)
+- `long`: Long push (approx. 2 seconds)
+- `touch`: Touch of the button's surface (only affective for WiFi Button +)
+
+The first usage of the pattern will create the binary sensor for the pattern. If the WiFi Button is pushed one time then a binary sensor for the `single` pattern will be created. The same applies for the other patterns. With the second usage of the pattern the binary sensors become fully functional.
+
+The buttons will give you feedback with its built-in LED:
+
+- white then green: Pattern was submitted successfully
+- white then red: There is a problem with the communication
+
+To use your myStrom WiFi Button in your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+binary_sensor:
+  - platform: mystrom
+```
+
+### {% linkable_title Setup of the myStrom Buttons %}
+
+After the Wifi Buttons are connected to your Wireless network, you have three minutes to set the actions for the push patterns. The fastest way is to use `curl`. Check the [documentation](https://mystrom.ch/wp-content/uploads/REST_API_WBP.txt) of the WiFi Button for further details about implementation (`http://` is replaced by `get://` or `post://`). `action` is the name of the corresponding push pattern.
+
+```bash
+$ curl -d "[action]=get://[IP address Home Assistant]:8123/api/mystrom?single%3D[ID of the button]" http://[IP address of the button]/api/v1/device/[MAC address of the button]
+{
+  "[MAC address of the button]": {
+    "type": "button",
+    "battery": true,
+    "reachable": true,
+    "meshroot": false,
+    "charge": true,
+    "voltage": 4.292,
+    "fw_version": "2.26",
+    "single": "get://[IP address Home Assistant]:8123/api/mystrom?single=[if of the button]",
+    "double": "",
+    "long": "",
+    "touch": ""
+  }
+}
+```
+
+A complete command to set the URL for a double click could look like the example below:
+
+```bash
+$ curl -d "double=get://192.168.1.3:8123/api/mystrom?double%3DButton1" http://192.168.1.12/api/v1/device/4D5F5D5CD553
+```
+
+<p class='note'>
+The firmware version 2.26 doesn't support TLS/SSL. This means that you are only able to use the WiFi Buttons if you are using plain-text communication between Home Assistant and the clients/entities.
+</p>