Introduction: Billboard Bot
I've been experimenting with a MAX7219 LED matrix display on Raspberry Pi and Arduino and decided to combine a message board with a line-following car to build a billboard bot. This project is just a proof-of-concept and more complex scenarios could be derived from it. For now, it just follows a line until it sees a stop sign denoted by a thick perpendicular black line and delivers a pre-programmed message.
Above photo shows an ultrasonic sensor mounted on the bumper but that is not needed/used on this use case.
This Instructable is a remix of:
1) Line-following robot (I'm the author of this Instructure)
Step 1: Parts
For this project, you'll need:
1) Line-following car similar to https://www.instructables.com/id/Yet-Another-Line-F...
2) Max7219 4 in 1 module. You could buy four 8x8 LED matrix modules and interconnect them together but I think buying 4 in 1 module is better.
Step 2: Putting Them Together
I used cardboard and glue gun to build a stand for the LED module as shown on the video.
Connect the 5 wires from the LED module to the Arduino pins. (The line-following car is already consuming most of the digital ports so I'm using analog ports as digital output instead.)
LED module-> Arduino
VCC->5V
GND->GND
DIN->A0;
CLK->A2
CS->A1
Step 3: Coding
Attached is the Arduino code I used to produce the video.
To change the scrolltext, simply change the line #17 to whatever you want to display.
const unsigned char scrollText[] PROGMEM = {" Happy New Year! \0"};
That's it. Happy New Year!