https://github.com/andrewn/pixel-matrix

Write to an LED Matrix connect to a Pi or Arduino via MQTT
https://github.com/andrewn/pixel-matrix

arduino johnny-five ledmatrix matrix mqtt pixel raspberry-pi

Last synced: 26 days ago
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Write to an LED Matrix connect to a Pi or Arduino via MQTT

• Host: GitHub
• URL: https://github.com/andrewn/pixel-matrix
• Owner: andrewn
• License: mit
• Created: 2015-10-25T18:00:33.000Z (about 9 years ago)
• Default Branch: master
• Last Pushed: 2015-10-28T17:25:01.000Z (about 9 years ago)
• Last Synced: 2024-05-02T05:54:09.805Z (6 months ago)
• Topics: arduino, johnny-five, ledmatrix, matrix, mqtt, pixel, raspberry-pi
• Language: JavaScript
• Homepage:
• Size: 145 KB
• Stars: 2
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
pixel-matrix

===

1. Connect an LED matrix to your Arduino/Genuino

2. `npm install`

3. Run `TOPIC= npm start`

4. Watch as your matrix dances

## Deets

### Connect an LED matrix to your Arduino

I used one of [these cheap ones from eBay](http://www.ebay.co.uk/itm/141777360808). It has an MAX7219 chip and works over SPI.

I kind of followed [these Johnny Five instructions](http://johnny-five.io/examples/led-matrix/) but with different pins on the Uno.

|  Matrix | Uno   |

|---------|-------|

|  VCC    |  5V   |

|  GND    |  GND  |

|  DIN    |  11   |

|  CS     |  10   |

|  CLK    |  11   |

### Connect an LED matrix to your Pi

[Pin diagram here](http://pi.gadgetoid.com/pinout/spi) and [here](https://github.com/nebrius/raspi-io/wiki/Pin-Information).

|  Matrix | Fn           | Pin num | Name     |

|---------|--------------|---------|----------|

|  VCC    |  5V          | 4       | 5v power |

|  GND    |  GND         | 6       | Ground   |

|  DIN    |  SPI1 MOSI   | 38      | GPIO20   |

|  CS     |  SPI1 CE2    | 36      | GPIO16   |

|  CLK    |  SPI1 SCLK   | 40      | GPIO21   |

### Pick a topic and run it

The node process listens on the MQTT topic specified by the `TOPIC` environment variable. It falls back to the random `andrewn/game-of-life/state` topic if none is given.

[http://gameoflife.surge.sh]() is publishing to this topic.

On a Pi, you also need to:

    npm install raspi-io

And add the `PLATFORM=pi` flag to `npm start` like this:

     sudo TOPIC= PLATFORM=pi npm start

You can autorun on boot:

     sudo cp pixel-matrix.service /etc/systemd/system/

     sudo systemctl enable pixel-matrix

### Data format

Your topic must supply a JSON-encode multi-dimensional array representing each pixel in the matrix.

For example, this will draw a heart:

    image = JSON.stringify(

      [

        "01100110",

        "10011001",

        "10000001",

        "10000001",

        "01000010",

        "00100100",

        "00011000",

        "00000000"

      ]

    );