An Arduino script to display messages on a MAX7219 module
Based on the 8×8 Matrix MAX7219 code available on the Arduino Playground
The MAX7219 requires 5 connections:
- 5V to VCC
- Ground to GND
- Pin 2 to DIN (data in)
- Pin 3 to CS (load)
- Pin 4 to CLK (clock)
The data pins listed above are within the first few lines of the main led_matrix_8x8.ino file if you wish to change them.
The original script was just written to output bitmaps, but had no preset ones in place, it was a raw template, essentially.
I wanted to alter this to allow for whole messages, or other fun symbols to be output to my board.
Currently, standard strings can be output with the display_string(String message) using standard letters (upper and lowercase), numbers, and some basic punctuation.
The speed at which string messages are displayed is determined by the letter_display_time variable which is the delay in milliseconds between showing each character.
For characters outside of the standard ANSI, (e.g. beer, heart, and poop) there is the display_symbol(String symbol) method, which looks up a character by name in the characters array. This allows new characters and symbols outside of ANSI to be easily added to the main array quite easily with any name.
The calls to each can be mixed together in any combination, either within the loop() to repeat a message/display, or within the setup() method to run once.
display_string("Wine smells better than ");
display_symbol("poop");Going forward, I'd like to make some of the following updates:
- Allow for messages to be scrolled in pixel columns/rows
- Add UTF8 support to the string methods so that all messages can be displayed as strings, rather than character by character for those outside of the ANSI range