mirror of
https://github.com/node-red/node-red-nodes.git
synced 2023-10-10 13:36:58 +02:00
131 lines
3.9 KiB
Markdown
131 lines
3.9 KiB
Markdown
node-red-node-pi-sense-hat
|
|
==========================
|
|
|
|
A <a href="http://nodered.org" target="_new">Node-RED</a> node to interact with
|
|
a Raspberry Pi Sense HAT.
|
|
|
|
## Pre-requisites
|
|
|
|
The Sense HAT python drivers need to be installed manually:
|
|
|
|
```
|
|
sudo apt-get update
|
|
sudo apt-get install sense-hat
|
|
sudo pip-3.2 install pillow
|
|
```
|
|
|
|
See the <a href="http://pythonhosted.org/sense-hat/" target="_new">driver documentation</a>
|
|
for more information.
|
|
|
|
|
|
## Install
|
|
|
|
Run the following command in your Node-RED user directory (typically `~/.node-red`):
|
|
|
|
npm install node-red-node-pi-sense-hat
|
|
|
|
## Usage
|
|
|
|
### 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.
|
|
|
|
#### Motion events
|
|
|
|
Motion events include readings from the accelerometer, gyroscope and magnetometer,
|
|
as well as the current compass heading. They are sent at a rate of approximately 10
|
|
per second. The `topic` is set to `motion` and the `payload` is an object with the
|
|
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
|
|
|
|
#### Environment events
|
|
|
|
Environment events include readings from the temperature, humidity and pressure
|
|
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
|
|
|
|
#### 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
|
|
|
|
|
|
### 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 from 0 to 7, a `*` to indicate the entire row
|
|
or column, or a range such as `3-6`.
|
|
|
|
`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`
|
|
|
|
To set a 3-pixel wide column to purple: `4-6,*,purple`
|
|
|
|
|
|
#### Rotate the screen
|
|
|
|
Format: `R<angle>`
|
|
|
|
`angle` must be 0, 90, 180 or 270.
|
|
|
|
#### Flip the screen
|
|
|
|
Format: `R<axis>`
|
|
|
|
`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.
|
|
|
|
If the text is a single character, it will be displayed without scrolling. To
|
|
scroll a single character, append a blank space after it - `"A "`.</p>
|
|
|
|
The following message properties can be used to customise the appearance:
|
|
|
|
- `msg.color` - 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`
|
|
|
|
#### Set the screen brightness
|
|
|
|
Format: `D<level>`
|
|
|
|
`level` must be 0 (low) or 1 (high).
|