Neopixel display and visualization node for node-red

This package provides animated visualizations for a squared neopixel matrix to be used as a display. It is developed to be used with the node-red-node-pi-neopixel package.

Dependencies

The package was tested on a Raspberry Pi Zero W and Node-Red v1.1.3.

• node-red-node-pi-neopixel

Support

If you find any bugs or want to request a feature, please open an issue.

Supported visualization and functionality

This library supports rectangular LED Matrices (Neopixel or WS2812), multiple Matrices can be connected in row to increase the width of the display.

Configuration

The neopixel display node consumes a message with payload and produces a message that will be handled by an rpi neopixel node. The payload type depends on what visualization is used.

• Node configuration
• Bar chart
• Line / Progress bar
• Text

Node configuration

A simple visualization could be configured like following:

The configured options for Visualization type, Background color and Foreground color can be overwritten in the message. Available options are:

Option	Message property	Available values
Visualization type	visualizationType	bars, line, text
Background color	backgroundColor	color *
Foreground color	foregroundColor	color *

* A color is represented as an array in RGB format. Example: [255, 0, 0] for red, [0, 255, 0] for green.

Example overwriting visualization options with a function node

return {
    visualizationType: 'bars',
    payload: [0, 1, 2, 3, 4, 5, 6, 7],
    backgroundColor: [255, 0, 0],
    foregroundColor: [0, 255, 0],
};

Bar chart

A bar chart requires an array of integer numbers as the payload. Each value of the array represents the height of the bar at the corresponding position.

Payload type: number[]

Example:

return {
    payload: [0, 1, 2, 3, 4, 5, 6, 7],
};

Line / Progress bar

A progress bar will fill the display vertically and display a horizontal bar of the given length in dots.

Payload type: number

Example:

return {
    payload: 6,
};

Text

The text will be displayed in a single line and there are currently several limitations. Only english characters are supported and each character takes 3 columns and 5 rows with one column between characters. A single 8x8 matrix can display 2 characters. Connecting 3 x 8x8 panels in a row increases the maximum displayed characters to 6.

Payload type: string

Additional options:

• offset: [number, number]: offset in x, y coordinates starting at top left corner of the display

return {
    payload: "OK",
    offset: [1, 1],
};