Documentation for the emoncms sensor. (#910)

* documentation for the emoncms sensor.

* add emoncms logo

* Changed functionality and better config variable names

* remove min / default value, this is defined by home assistant itselve.
The component was wrongfully adding scan_interval to voloptuous schema
twice as it was already defined in config_velidation helper so
i should not try to redefine it either

* switch logo to their official logo

source/_components/sensor.emoncms.markdown

@@ -0,0 +1,147 @@
+---
+layout: page
+title: "Emoncms Sensor"
+description: "Instructions on how to integrate emoncms feeds as sensors into Home Assistant."
+date: 2016-09-08 00:15
+logo: emoncms.png
+sidebar: true
+comments: false
+sharing: true
+footer: true
+ha_category: Sensor
+---
+
+
+The `emoncms` sensor platform creates sensors for the feeds available in your local or cloud based version of [emoncms](https://emoncms.org).
+
+To enable this sensor, add the following lines to your `configuration.yaml`, it will list all feeds as a sensor:
+
+```yaml
+# Example configuration.yaml entry using cloud based emoncms
+sensor:
+  platform: emoncms
+  api_key: put your emoncms read api key here
+  url: https://emoncms.org
+  id: 1
+```
+
+## {% linkable_title Configuration variables %}
+
+- **api_key** (*Required*): The read api key for your emoncms user.
+- **url** (*Required*): The base url of emoncms, use "https://emoncms.org" for the cloud based version.
+- **id** (*Required*): Positive Integer identifier for the sensor. Must be unique if you specify multiple emoncms sensors.
+- **include_only_feed_id** (*optional*): Positive integer list of emoncms feed id's. Only the feeds with feed id's specified here will be displayed. Can not be specified if `exclude_feed_id` is specified.
+- **exclude_feed_id** (*optional*): Positive integer list of emoncms feed id's. All the feeds will be displayed as sensors except the ones listed here. Can not be specified if `include_only_feed_id` is specified.
+- **sensor_names** (*optional*): Dictionary of names for the sensors created that are created based on feedid. The dictionary consists of feedid:name pairs. Sensors for feeds with their feedid mentioned here will get the chosen name instead of the default name
+- **value_template** (*Optional*): Defines a [template](/topics/templating/) to alter the feed value.
+- **scan_interval** (*Optional*): Defines the update interval of the sensor in seconds.
+- **unit_of_measurement** (*Optional*): Defines the unit of measurement of for all the sensors. default is "W".
+
+## {% linkable_title Default naming scheme %}
+
+The names of the sensors created by this component, will be a combination of static text, `id` from the config and `feedid` from the emoncms feed, unless `sensor_names` is used.
+An example name would be "emoncms1_feedid_10"
+
+## {% linkable_title Examples %}
+
+In this section you find some more examples of how this sensor can be used.
+
+```yaml
+# Display only feeds with their feed id's specified in "include_only_feed_id"
+sensor:
+  - platform: emoncms
+    api_key: put your emoncms read api key here
+    url: https://emoncms.org
+    id: 1
+    unit_of_measurement: "W"
+    include_only_feed_id:
+      - 107
+      - 106
+      - 105
+```
+
+
+```yaml
+# Display all feeds except feeds with their feed id specified in "exclude_feed_id" 
+sensor:
+  - platform: emoncms
+    api_key: put your emoncms read api key here
+    url: https://emoncms.org
+    id: 1
+    unit_of_measurement: "KWH" 
+    exclude_feed_id:
+      - 107
+      - 106
+      - 105
+```
+
+
+```yaml
+# Display only feeds with their feed id's specified in "include_only_feed_id" and give the feed sensors a name using "sensor_names". You don't have to specify all feeds names in "sensor_names", the remaining sensor names will be chosen based on "id" and the emoncms feedid
+sensor:
+  - platform: emoncms
+    api_key: put your emoncms read api key here
+    url: https://emoncms.org   
+    id: 1
+    unit_of_measurement: "KW" 
+    include_only_feed_id:
+      - 5
+      - 18
+      - 29
+      - 48
+      - 61
+      - 110
+      - 116
+      - 120
+    sensor_names:
+      5: "feed 1"
+      18: "feed 2"
+      29: "feed 3"
+      48: "kwh feed"
+      61: "amp feed"
+      110: "watt feed"
+```
+
+
+```yaml
+# Use a "value_template" to add 1500 to the feed value for all specified feed id's in "include_feed_id"
+sensor:
+  - platform: emoncms
+    api_key: put your emoncms read api key here
+    url: https://emoncms.org
+    scan_interval: 15
+    id: 1
+    value_template: {% raw %}"{{ value | float + 1500 }}"{% endraw %}
+    include_only_feed_id:
+      - 107
+      - 106
+      - 105
+      - 61
+```
+
+
+```yaml
+# Display feeds from the same emoncms instance with 2 groups of feeds, diffrent scan_interval and a diffrent unit_of_measurement
+sensor:
+  - platform: emoncms
+    api_key: put your emoncms read api key here
+    url: https://emoncms.org
+    scan_interval: 30
+    id: 1
+    unit_of_measurement: "W" 
+    include_only_feed_id:
+      - 107
+      - 106
+      - 105
+  - platform: emoncms
+    api_key:  put your emoncms read api key here
+    url: https://emoncms.org
+    id: 2
+    scan_interval: 60
+    unit_of_measurement: "A" 
+    include_only_feed_id:
+      - 108
+      - 109
+      - 110
+      - 61
+```