Example Code for Arduino-Scrolling Text and Bouncing Balls

Hardware Preparation

• DFRduino UNO R3 x1
• DFR0471 x1
• DuPont cables

Software Preparation

• Arduino IDE Click to Download Arduino IDE from Arduino®
• Libraries: Adafruit-GFX, RGB-matrix-Panel, Adafruit_BusIO
• How to install the library?

Wiring Diagram

Note: It needs an external power supply, the USB is only 5V@500mA, not enough power.

Other Preparation Work

No additional preparatory tasks beyond hardware connection and software installation.

Sample Code

/***************************************************
*
* For 32x16 RGB LED matrix.
*
* @author lg.gang
* @version  V1.0
* @date  2016-10-28
*
* GNU Lesser General Public License.
* See <http://www.gnu.org/licenses/> for details.
* All above must be included in any redistribution
* ****************************************************/

#include <Adafruit_GFX.h>   // Core graphics library
#include <RGBmatrixPanel.h> // Hardware-specific library

// Similar to F(), but for PROGMEM string pointers rather than literals
#define F2(progmem_ptr) (const __FlashStringHelper *)progmem_ptr

#define CLK 8  // MUST be on PORTB! (Use pin 11 on Mega)
#define LAT A3
#define OE  9
#define A   A0
#define B   A1
#define C   A2
// Last parameter = 'true' enables double-buffering, for flicker-free,
// buttery smooth animation.  Note that NOTHING WILL SHOW ON THE DISPLAY
// until the first call to swapBuffers().  This is normal.
RGBmatrixPanel matrix(A, B, C, CLK, LAT, OE, true);
// Double-buffered mode consumes nearly all the RAM available on the
// Arduino Uno -- only a handful of free bytes remain.  Even the
// following string needs to go in PROGMEM:

const char str[] PROGMEM = "Welcome to DFrobot 32x16 RGB LED Matrix";
int    textX   = matrix.width(),
       textMin = sizeof(str) * -12,
       hue     = 0;
int8_t ball[3][4] = {
  {  3,  0,  1,  1 }, // Initial X,Y pos & velocity for 3 bouncy balls
  { 17, 15,  1, -1 },
  { 27,  4, -1,  1 }
};
static const uint16_t PROGMEM ballcolor[3] = {
  0x0080, // Green=1
  0x0002, // Blue=1
  0x1000  // Red=1
};

void setup() {
  matrix.begin();
  matrix.setTextWrap(false); // Allow text to run off right edge
  matrix.setTextSize(2);
}

void loop() {
  byte i;

  // Clear background
  matrix.fillScreen(0);

  // Bounce three balls around
  for(i=0; i<3; i++) {
    // Draw 'ball'
    matrix.fillCircle(ball[i][0], ball[i][1], 5, pgm_read_word(&ballcolor[i]));
    // Update X, Y position
    ball[i][0] += ball[i][2];
    ball[i][1] += ball[i][3];
    // Bounce off edges
    if((ball[i][0] == 0) || (ball[i][0] == (matrix.width() - 1)))
      ball[i][2] *= -1;
    if((ball[i][1] == 0) || (ball[i][1] == (matrix.height() - 1)))
      ball[i][3] *= -1;
  }

  // Draw big scrolly text on top
  matrix.setTextColor(matrix.ColorHSV(hue, 255, 255, true));
  matrix.setCursor(textX, 1);
  matrix.print(F2(str));

  // Move text left (w/wrap), increase hue
  if((--textX) < textMin) textX = matrix.width();
  hue += 7;
  if(hue >= 1536) hue -= 1536;

  // Update display
  matrix.swapBuffers(false);
}

Result

Sample Code 2: Display: "Welcome to DFrobot 32x16 RGB LED Matrix"