Add out node

hardware/sensehat/README.md

@@ -28,7 +28,8 @@ Run the following command in your Node-RED user directory (typically `~/.node-re
 
 ### Input Node
 
-This node sends readings from the various sensors on the Sense HAT, grouped into three sets; motion events, environment events and joystick events.
+This node sends readings from the various sensors on the Sense HAT, grouped into
+three sets; motion events, environment events and joystick events.
 
 #### Motion events
 
@@ -38,9 +39,9 @@ per second. The `topic` is set to `motion` and the `payload` is an object with t
 following values:
 
   - `acceleration.x/y/z` : the acceleration intensity in Gs
-  - `gyroscope.x/y/z` : the rotational intensity in radians/s
-  - `orientation.roll/pitch/yaw` : the angle of the axis in degrees
-  - `compass` : the direction of North in degrees
+  -`gyroscope.x/y/z` : the rotational intensity in radians/s
+  -`orientation.roll/pitch/yaw` : the angle of the axis in degrees
+  -`compass` : the direction of North in degrees
 
 #### Environment events
 
@@ -49,17 +50,69 @@ sensors. They are sent at a rate of approximately 1 per second.  The `topic`
 is set to `environment` and the `payload` is an object
 with the following values:
 
-  - `temperature` : degrees Celsius
-  - `humidity` : percentage of relative humidity
-  - `pressure` : Millibars
+  -`temperature` : degrees Celsius
+  -`humidity` : percentage of relative humidity
+  -`pressure` : Millibars
 
 #### Joystick events
 
 Joystick events are sent when the Sense HAT joystick is interacted with. The
 `topic` is set to `joystick` and the `payload` is an object with the following values:
 
-  - `key` : one of `UP`, `DOWN`, `LEFT`, `RIGHT`, `ENTER`
-  - `state` : the state of the key:
-    - `0` : the key has been released
-    - `1` : the key has been pressed
-    - `2` : the key is being held down
+  -`key` : one of `UP`, `DOWN`, `LEFT`, `RIGHT`, `ENTER`
+  -`state` : the state of the key:
+    -`0` : the key has been released
+    -`1` : the key has been pressed
+    -`2` : the key is being held down
+
+
+### Output Node
+
+This node sends commands to the 8x8 LED display on the Sense HAT.
+
+Commands are sent to the node in `msg.payload`. Multiple commands can
+be sent in a single message by separating them with newline (\n) characters.
+
+#### Set the colour of individual pixels
+
+Format: `<x>,<y>,<colour>`
+
+`x` and `y` must either be a value in the range 0-7, or `*` to indicate the entire row or column.
+
+`colour` must be one of:
+
+    - the well-known <a href="https://en.wikipedia.org/wiki/Web_colors" target="_new">HTML colour names</a>
+     - eg `red` or `aquamarine`,
+    - the <a href="http://cheerlights.com/cheerlights-api/">CheerLights colour names</a>,
+    - a HEX colour value - eg `#aa9900`
+    - an RGB triple - `190,255,0`
+    - or simply `off`
+
+To set the entire screen to red: `*,*,red`
+
+To set the four corners of the display to red, green (#00ff00), yellow and blue (0,0,255):
+
+`0,0,red,0,7,#00ff00,7,7,yellow,7,0,0,0,255`
+
+#### Rotate the screen
+
+Format: `R&lt;angle&gt;`
+
+`angle` must be 0, 90, 180 or 270.
+
+#### Flip the screen
+
+Format: `R&lt;axis&gt;`
+
+`axis` must be either `H` or `V` to flip on the horizontal or vertical axis respectively.
+
+#### Scroll a message
+
+If `msg.payload` is not recognised as any of the above commands, it is treated
+as a text message to be scrolled across the screen.
+
+The following message properties can be used to customise the appearance:
+
+    - `msg.colour` - the colour of the text, default: `white`
+    - `msg.background` - the colour of the background, default: `off`
+    - `msg.speed` - the scroll speed. A value in the range 1 (slower) to 5 (faster), default: `3`