Adds simulated sensor (#4712)

* Create sensor.simulated.markdown

* Fix seed ref

* Update sensor.simulated.markdown

* Update sensor.simulated.markdown

* Update sensor.simulated.markdown

source/_components/sensor.simulated.markdown

@@ -0,0 +1,94 @@
+---
+layout: page
+title: "Simulated sensor"
+description: "Component for simulating a numerical sensor."
+date: 2018-02-20 08:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: home-assistant.png
+ha_category: Sensor
+ha_iot_class: "Local Polling"
+ha_release: 0.65
+---
+
+This component provides a simulated sensor that generates a time-varying signal ```V(t)``` given by the [function](https://en.wikipedia.org/wiki/Sine_wave):
+
+ ```
+ V(t) = M + A sin((2 pi (t - t_0) / w) + P) + N(s)
+ ```
+
+where:
+
+- **M** = the [mean](https://en.wikipedia.org/wiki/Mean) value of the sensor
+- **A** = the [amplitude](https://en.wikipedia.org/wiki/Amplitude) of the periodic contribution
+- **t** = the time when a value is generated
+- **t_0** = the time when the sensor is started
+- **w** = the time [period](https://en.wikipedia.org/wiki/Periodic_function) in seconds for a single complete cycle of the periodic contribution
+- **P** = the [phase](https://en.wikipedia.org/wiki/Phase_(waves)) offset to add to the periodic contribution, in units of degrees
+- **N(s)** = the random [Gaussian noise](https://en.wikipedia.org/wiki/Gaussian_noise) with spread **s**
+
+A simulated sensor with default values can be added to home-assistant using the following config:
+
+```yaml
+sensor:
+  - platform: simulated
+```
+
+To give an example of simulating real world data, a simulated relative humidity sensor (in %) can be added using the following config:
+
+```yaml
+sensor:
+  - platform: simulated
+    name: 'simulated relative humidity'
+    unit: '%'
+    amplitude: 0 # Turns off the periodic contribution
+    mean: 50
+    spread: 10
+    seed: 999
+```
+
+Configuration variables:
+{% configuration %}
+name:
+  description: The name of the sensor
+  required: false
+  default: Defaults to 'simulated'
+  type: string
+unit:
+  description: The unit to apply
+  required: false
+  default: Defaults to 'value'
+  type: string
+amplitude:
+  description: The amplitude of periodic contribution
+  required: false
+  default: 1
+  type: float
+mean:
+  description: The mean level of the sensor
+  required: false
+  default: 0
+  type: float
+period:
+  description: The time in seconds for one complete oscillation of the periodic contribution
+  required: false
+  default: 0
+  type: seconds
+phase:
+  description: The phase offset (in degrees) to apply to the periodic component
+  required: false
+  default: 0
+  type: float
+seed:
+  description: The [seed](https://docs.python.org/3.6/library/random.html#random.seed) value for the random noise component
+  required: false
+  default: 999
+  type: int
+spread:
+  description: The spread is the range of the randomly distributed values about their mean. This is sometimes referred to as the Full Width at Half Maximum ([FWHM](https://en.wikipedia.org/wiki/Full_width_at_half_maximum)) of the random distribution
+  required: false
+  default: None
+  type: float
+{% endconfiguration %}