- Discrete LEDs
- Dot/Bar LEDs
- Matrix LEDs
- 7-Seg LEDs
- Serial -- Software
- Serial -- Hardware
- RS-232 via the MAX3232
- I2C -- EEPROM
- I2C -- DS1307 Real Time Clock
- 1-Wire -- DS18B20, Powered, Single-Drop
- 1-Wire -- DS18B20, Powered, Multi-Drop
- 1-Wire -- DS18B20, Parasitic, Multi-Drop
- TI Link Protocol -- Calculator Demo
- Infrared Communication
- MIDI -- Output Demo
- MIDI -- Input Demo
- MIDI to Analog Synth
8X8 LED Matrix -- via MAX7219
In many ways, this really is the golden age of DIY electronics. Every day, new and wondrous parts become available which would have staggered me 55 years ago (when I built my first project with a CK722 transistor). And the prices for our avocation just keep dropping and dropping, primarily because of what Marco Polo started. This project is a potent example of that.
Here we have an amazingly beautiful 8X8 LED matrix LED, coupled with the powerful MAX7219 decoder chip, on a PCB, with connector pins thrown in, all for less than three dollars! You might have to wait several weeks as it winds its way from China, but the wait is worth it. I bought the unit I use by means of Amazon. There are a number of suppliers of this module there; here's a representative one:
Now apart from the laughable price, here's the cool part. With this module you can get 256 different gorgeous characters, and with only three port lines required. The MAX7219 handles most of the row/column messiness, while the character data I've provided with this project takes care of the rest. The circuit layout is a snap:
And there are special effects, too! Things like fading, blinking, sliding characters in all four directions, marquee effects and more. Again, the PMP unit I've written relieves you of the drudgery. This demo project goes through all of the options to give you a feel for what's possible.
You might also note that the character data I've come up with handles virtually all diacritical marks and accents used in languages other than English.
Three bucks, including shipping!
Click to get the source code.
Click to get the schematic PDF.
Next Project: 7-Segment Display -- Direct Drive