you can modify this project by changing the number of the led matrix if you have more than one led display ,
you can also display a store message.
Demonstration
We connect VCC and GND to Arduino in a case you have one display but if you have more than one that I highlyrecommended connecting to external power supply a power bank will do the trick, connect the DIN to digital pin 12, CLK digital pin 11, CS digital pin 10.
The HC-06 which is it a serial communication Bluetooth module it's working always as a slave so you can use your smartphone to send a message to display it
by me, I use Bluetooth Terminal app to send my messages.
Connect TX of the module to RX pin of the Arduino.
NOTE:
Do not connect the TX pin of the Arduino to RX of the Bluetooth module because it's workingin the range of 3.3v so any 5v signal will destroy the module chip, so be aware too that.
Install LedControl library :- LedControl.h
Arduino code
#include <avr/pgmspace.h> #include <LedControl.h> char b[255]; // for uart input String abc=""; const int numDevices = 1; // number of MAX7219s used const long scrollDelay = 75; // scrolling speed unsigned long bufferLong [14] = {0}; // DIN, CLK, CS, #chips LedControl lc=LedControl(12,11,10,numDevices); void setup(){ Serial.begin(9600); for (int x=0; x<numDevices; x++) { lc.shutdown(x,false); //The MAX72XX is in power-saving mode on startup lc.setIntensity(x,8); // Set the brightness to default value lc.clearDisplay(x); // and clear the display } } void loop(){ while(Serial.available()> 0) // Wait for data incoming { abc = Serial.readString(); // Put the data in a String variable Serial.println(abc.length()-2); // } for(word x=0;x≤abc.length();x++) // After reading the message now we count it how // many characters { b[x] = abc.charAt(x); // Define the character word b_ascii_value = b[x]; // Convert the character to ascii code loadBufferLong(b_ascii_value); // Display the character and move it one step delay(10); } loadBufferLong(0x20); // Character for space which is importing to separated the end loadBufferLong(0x20); // of the message from the beginning } /////////////////////////////////////////////////////////////////////////////////////////////////////////////////// const unsigned char font5x7 [] PROGMEM = { //Numeric Font Matrix (Arranged as 7x font data + 1x kerning data) B00000000, //Space (Char 0x20) B00000000, B00000000, B00000000, B00000000, B00000000, B00000000, 6, B10000000, //! B10000000, B10000000, B10000000, B00000000, B00000000, B10000000, 2, B10100000, //" B10100000, B10100000, B00000000, B00000000, B00000000, B00000000, 4, B01010000, //# B01010000, B11111000, B01010000, B11111000, B01010000, B01010000, 6, B00100000, //$ B01111000, B10100000, B01110000, B00101000, B11110000, B00100000, 6, B11000000, //% B11001000, B00010000, B00100000, B01000000, B10011000, B00011000, 6, B01100000, //& B10010000, B10100000, B01000000, B10101000, B10010000, B01101000, 6, B11000000, //' B01000000, B10000000, B00000000, B00000000, B00000000, B00000000, 3, B00100000, //( B01000000, B10000000, B10000000, B10000000, B01000000, B00100000, 4, B10000000, //) B01000000, B00100000, B00100000, B00100000, B01000000, B10000000, 4, B00000000, //* B00100000, B10101000, B01110000, B10101000, B00100000, B00000000, 6, B00000000, //+ B00100000, B00100000, B11111000, B00100000, B00100000, B00000000, 6, B00000000, //, B00000000, B00000000, B00000000, B11000000, B01000000, B10000000, 3, B00000000, //- B00000000, B11111000, B00000000, B00000000, B00000000, B00000000, 6, B00000000, //. B00000000, B00000000, B00000000, B00000000, B11000000, B11000000, 3, B00000000, /// B00001000, B00010000, B00100000, B01000000, B10000000, B00000000, 6, B01110000, //0 B10001000, B10011000, B10101000, B11001000, B10001000, B01110000, 6, B01000000, //1 B11000000, B01000000, B01000000, B01000000, B01000000, B11100000, 4, B01110000, //2 B10001000, B00001000, B00010000, B00100000, B01000000, B11111000, 6, B11111000, //3 B00010000, B00100000, B00010000, B00001000, B10001000, B01110000, 6, B00010000, //4 B00110000, B01010000, B10010000, B11111000, B00010000, B00010000, 6, B11111000, //5 B10000000, B11110000, B00001000, B00001000, B10001000, B01110000, 6, B00110000, //6 B01000000, B10000000, B11110000, B10001000, B10001000, B01110000, 6, B11111000, //7 B10001000, B00001000, B00010000, B00100000, B00100000, B00100000, 6, B01110000, //8 B10001000, B10001000, B01110000, B10001000, B10001000, B01110000, 6, B01110000, //9 B10001000, B10001000, B01111000, B00001000, B00010000, B01100000, 6, B00000000, //: B11000000, B11000000, B00000000, B11000000, B11000000, B00000000, 3, B00000000, //; B11000000, B11000000, B00000000, B11000000, B01000000, B10000000, 3, B00010000, //< B00100000, B01000000, B10000000, B01000000, B00100000, B00010000, 5, B00000000, //= B00000000, B11111000, B00000000, B11111000, B00000000, B00000000, 6, B10000000, //> B01000000, B00100000, B00010000, B00100000, B01000000, B10000000, 5, B01110000, //? B10001000, B00001000, B00010000, B00100000, B00000000, B00100000, 6, B01110000, //@ B10001000, B00001000, B01101000, B10101000, B10101000, B01110000, 6, B01110000, //A B10001000, B10001000, B10001000, B11111000, B10001000, B10001000, 6, B11110000, //B B10001000, B10001000, B11110000, B10001000, B10001000, B11110000, 6, B01110000, //C B10001000, B10000000, B10000000, B10000000, B10001000, B01110000, 6, B11100000, //D B10010000, B10001000, B10001000, B10001000, B10010000, B11100000, 6, B11111000, //E B10000000, B10000000, B11110000, B10000000, B10000000, B11111000, 6, B11111000, //F B10000000, B10000000, B11110000, B10000000, B10000000, B10000000, 6, B01110000, //G B10001000, B10000000, B10111000, B10001000, B10001000, B01111000, 6, B10001000, //H B10001000, B10001000, B11111000, B10001000, B10001000, B10001000, 6, B11100000, //I B01000000, B01000000, B01000000, B01000000, B01000000, B11100000, 4, B00111000, //J B00010000, B00010000, B00010000, B00010000, B10010000, B01100000, 6, B10001000, //K B10010000, B10100000, B11000000, B10100000, B10010000, B10001000, 6, B10000000, //L B10000000, B10000000, B10000000, B10000000, B10000000, B11111000, 6, B10001000, //M B11011000, B10101000, B10101000, B10001000, B10001000, B10001000, 6, B10001000, //N B10001000, B11001000, B10101000, B10011000, B10001000, B10001000, 6, B01110000, //O B10001000, B10001000, B10001000, B10001000, B10001000, B01110000, 6, B11110000, //P B10001000, B10001000, B11110000, B10000000, B10000000, B10000000, 6, B01110000, //Q B10001000, B10001000, B10001000, B10101000, B10010000, B01101000, 6, B11110000, //R B10001000, B10001000, B11110000, B10100000, B10010000, B10001000, 6, B01111000, //S B10000000, B10000000, B01110000, B00001000, B00001000, B11110000, 6, B11111000, //T B00100000, B00100000, B00100000, B00100000, B00100000, B00100000, 6, B10001000, //U B10001000, B10001000, B10001000, B10001000, B10001000, B01110000, 6, B10001000, //V B10001000, B10001000, B10001000, B10001000, B01010000, B00100000, 6, B10001000, //W B10001000, B10001000, B10101000, B10101000, B10101000, B01010000, 6, B10001000, //X B10001000, B01010000, B00100000, B01010000, B10001000, B10001000, 6, B10001000, //Y B10001000, B10001000, B01010000, B00100000, B00100000, B00100000, 6, B11111000, //Z B00001000, B00010000, B00100000, B01000000, B10000000, B11111000, 6, B11100000, //[ B10000000, B10000000, B10000000, B10000000, B10000000, B11100000, 4, B00000000, //(Backward Slash) B10000000, B01000000, B00100000, B00010000, B00001000, B00000000, 6, B11100000, //] B00100000, B00100000, B00100000, B00100000, B00100000, B11100000, 4, B00100000, //^ B01010000, B10001000, B00000000, B00000000, B00000000, B00000000, 6, B00000000, //_ B00000000, B00000000, B00000000, B00000000, B00000000, B11111000, 6, B10000000, //` B01000000, B00100000, B00000000, B00000000, B00000000, B00000000, 4, B00000000, //a B00000000, B01110000, B00001000, B01111000, B10001000, B01111000, 6, B10000000, //b B10000000, B10110000, B11001000, B10001000, B10001000, B11110000, 6, B00000000, //c B00000000, B01110000, B10001000, B10000000, B10001000, B01110000, 6, B00001000, //d B00001000, B01101000, B10011000, B10001000, B10001000, B01111000, 6, B00000000, //e B00000000, B01110000, B10001000, B11111000, B10000000, B01110000, 6, B00110000, //f B01001000, B01000000, B11100000, B01000000, B01000000, B01000000, 6, B00000000, //g B01111000, B10001000, B10001000, B01111000, B00001000, B01110000, 6, B10000000, //h B10000000, B10110000, B11001000, B10001000, B10001000, B10001000, 6, B01000000, //i B00000000, B11000000, B01000000, B01000000, B01000000, B11100000, 4, B00010000, //j B00000000, B00110000, B00010000, B00010000, B10010000, B01100000, 5, B10000000, //k B10000000, B10010000, B10100000, B11000000, B10100000, B10010000, 5, B11000000, //l B01000000, B01000000, B01000000, B01000000, B01000000, B11100000, 4, B00000000, //m B00000000, B11010000, B10101000, B10101000, B10001000, B10001000, 6, B00000000, //n B00000000, B10110000, B11001000, B10001000, B10001000, B10001000, 6, B00000000, //o B00000000, B01110000, B10001000, B10001000, B10001000, B01110000, 6, B00000000, //p B00000000, B11110000, B10001000, B11110000, B10000000, B10000000, 6, B00000000, //q B00000000, B01101000, B10011000, B01111000, B00001000, B00001000, 6, B00000000, //r B00000000, B10110000, B11001000, B10000000, B10000000, B10000000, 6, B00000000, //s B00000000, B01110000, B10000000, B01110000, B00001000, B11110000, 6, B01000000, //t B01000000, B11100000, B01000000, B01000000, B01001000, B00110000, 6, B00000000, //u B00000000, B10001000, B10001000, B10001000, B10011000, B01101000, 6, B00000000, //v B00000000, B10001000, B10001000, B10001000, B01010000, B00100000, 6, B00000000, //w B00000000, B10001000, B10101000, B10101000, B10101000, B01010000, 6, B00000000, //x B00000000, B10001000, B01010000, B00100000, B01010000, B10001000, 6, B00000000, //y B00000000, B10001000, B10001000, B01111000, B00001000, B01110000, 6, B00000000, //z B00000000, B11111000, B00010000, B00100000, B01000000, B11111000, 6, B00100000, //{ B01000000, B01000000, B10000000, B01000000, B01000000, B00100000, 4, B10000000, //| B10000000, B10000000, B10000000, B10000000, B10000000, B10000000, 2, B10000000, //} B01000000, B01000000, B00100000, B01000000, B01000000, B10000000, 4, B00000000, //~ B00000000, B00000000, B01101000, B10010000, B00000000, B00000000, 6, B01100000, // (Char 0x7F) B10010000, B10010000, B01100000, B00000000, B00000000, B00000000, 5 }; void scrollFont() { for (int counter=0x20;counter<0x80;counter++){ loadBufferLong(counter); delay(500); } } // Scroll Message void scrollMessage( unsigned char * messageString) { int counter = 0; int myChar=0; do { // read back a char myChar = pgm_read_byte_near(messageString + counter); if (myChar != 0){ loadBufferLong(myChar); } counter++; } while (myChar != 0); } // Load character into scroll buffer void loadBufferLong(int ascii){ if (ascii => 0x20 && ascii <=0x7f){ for (int a=0;a<7;a++){ // Loop 7 times for a 5x7 font unsigned long c = pgm_read_byte_near(font5x7 + ((ascii - 0x20) * 8) + a); // Index into character table to get row data unsigned long x = bufferLong [a*2]; // Load current scroll buffer x = x | c; // OR the new character onto end of current bufferLong [a*2] = x; // Store in buffer } byte count = pgm_read_byte_near(font5x7 +((ascii - 0x20) * 8) + 7); // Index into character table for kerning data for (byte x=0; x<count;x++){ rotateBufferLong(); printBufferLong(); delay(scrollDelay); } } } // Rotate the buffer void rotateBufferLong(){ for (int a=0;a<7;a++){ // Loop 7 times for a 5x7 font unsigned long x = bufferLong [a*2]; // Get low buffer entry byte b = bitRead(x,31); // Copy high order bit that gets lost in rotation x = x<<1; // Rotate left one bit bufferLong [a*2] = x; // Store new low buffer x = bufferLong [a*2+1]; // Get high buffer entry x = x<<1; // Rotate left one bit bitWrite(x,0,b); // Store saved bit bufferLong [a*2+1] = x; // Store new high buffer } } // Display Buffer on LED matrix void printBufferLong(){ for (int a=0;a<7;a++){ // Loop 7 times for a 5x7 font unsigned long x = bufferLong [a*2+1]; // Get high buffer entry byte y = x; // Mask off first character lc.setRow(3,a,y); // Send row to relevent MAX7219 chip x = bufferLong [a*2]; // Get low buffer entry y = (x>>24); // Mask off second character lc.setRow(2,a,y); // Send row to relevent MAX7219 chip y = (x>>16); // Mask off third character lc.setRow(1,a,y); // Send row to relevent MAX7219 chip y = (x>>8); // Mask off forth character lc.setRow(0,a,y); // Send row to relevent MAX7219 chip } }