Fetching data to RGB backpack

[simon_schvartzman]

Hi, I would like to know the easiest way to dynamically fetch data to the RGB backpack to be displayed on the matrix.

In other words I would like to have another Arduino sending data to the backpack.

Looking forward for help!

[Michael]

The easiest way to communicate is with a serial connection. The board has a 6-pin serial header, so just learn about Arduino serial communication and you are good to go.

[simon_schvartzman]

Thanks Michael, that’s very useful.

Regards

[simon_schvartzman]

Hi, for those who need help with this subject

CODE FOR THE UNO SENDING DATA TO THE BACKPACK

/*
 Simple sketch to demostrate how to send data from 
 an Arduino Uno to the nootropic RGB Matrix backpack
 This is the code on the Uno Side
 The program will do the following:
 - send a command (Blue Square)
 - wait 5 secs
 - send a command to clear the display (Clear)

Connections
UNO            BackPack FTDI Connector 
Pin 10 (Rx)    Pin # 2 (near the +5V terminal)
Pin 11 (Tx)    Pin # 3
Ground         Pin # 6 (right most pin near the Power Jack)     
*/

#include <SoftwareSerial.h>    // we will use a soft serial
#define Serial_baud_rate  9600 // Comm speed between the boards                                  
#define serial_Rxd          10 // Rx to be connected to Tx on the backpack                                   
#define serial_Txd          11 // Tx to be connected to Rx on the backpack

SoftwareSerial BP_serial(serial_Rxd, serial_Txd);    //Define the soft serial

String inputString = "";         // a string to hold incoming data

void setup() {
  Serial.begin (9600);        //open main Serial port
  Serial.println ("start");

  BP_serial.begin(Serial_baud_rate); // Open the serial port to connect to the backpack
}

void loop() 
{
  BP_serial.print ("Blue Square"); //Backpack will display a Blue Square
  BP_serial.print (char(10));      //line has to be terminated with line feed (/n)
  delay (7000);
  BP_serial.print ("Clear");       //Backpack will clear the matrix
  BP_serial.print (char(10));
  delay (2000);
  SerialRead ();                   //Read feedback (echo) from backpack
}

/*
 Read the Serial connection
 */
void SerialRead() 
{
  while (BP_serial.available()) 
  {
    // get the new byte:
    char inChar = (char)BP_serial.read();
    // add it to the inputString:
    inputString += inChar;
    if (inChar == '\n') // end of line received
    {
      Serial.println (inputString);
      inputString = ""; //clean up for next reading
    }
  }
}

CODE FOR THE BACKPACK

// Simple sketch (BackPack) to show how to receive commands from an Arduino Uno
// with the nootropic RGB BackPack.
// Before connecting to the Uno you can test the program by sending
// the commands using the IDE Serial Monitor. Just remember to set it up
// 
// Writen by Simon Schvartzman
// based on:

// testshapes demo for Adafruit RGBmatrixPanel library.
// Demonstrates the drawing abilities of the RGBmatrixPanel library.
// For 32x32 RGB LED matrix:
// http://www.adafruit.com/products/607

// Written by Limor Fried/Ladyada & Phil Burgess/PaintYourDragon
// for Adafruit Industries.
// BSD license, all text above must be included in any redistribution.

// Connections
// UNO            BackPack FTDI Connector 
// Pin 10 (Rx)    Pin # 2 (near the +5V terminal)
// Pin 11 (Tx)    Pin # 3
// Ground         Pin # 6 (right most pin near the Power Jack)          

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

#define CLK 8 // MUST be on PORTB! (Use pin 11 on Mega)
#define OE  9
#define LAT 10
#define A   A0
#define B   A1
#define C   A2
#define D   A3

RGBmatrixPanel matrix(A, B, C, D, CLK, LAT, OE, false);

String inputString = "";         // a string to hold incoming data
boolean stringComplete = false;  // flag to mark the string is complete

void setup() 
{
  Serial.begin (9600);
  matrix.begin();
}

void loop() 
{
  //Serial.println ("Hello World");
  // print the string when a newline arrives:
  if (stringComplete == true)
  {
    Serial.println(inputString);
    //read the command and act accordingly   
    if (inputString == "Blue Square")
    {
      BlueSquare ();
    }
    
    if (inputString == "Clear")
    {
      clearMatrix ();
    }

    // clear the string:
    inputString = "";
    stringComplete = false;
  }
  delay (5000);
  //inputString = "";
  //serialRead();
}

void BlueSquare ()
{
    //fill in a rectangle in blue
    for (int i = 10; i < 22; i = i + 1)
    {
      for (int j = 10; j < 22; j = j + 1)
      {
        matrix.drawPixel(i, j, matrix.Color333(0, 0, 7)); 
        delay (15);
      }
    }
}

void clearMatrix()
{
  // fill the screen with 'black'
  matrix.fillScreen(matrix.Color333(0, 0, 0));
}

/*
  SerialEvent occurs whenever a new data comes in the
 hardware serial RX.  This routine is run between each
 time loop() runs, so using delay inside loop can delay
 response.  Multiple bytes of data may be available.
 */

void serialEvent() {
  while (Serial.available()) {
    // get the new byte:
    char inChar = (char)Serial.read();
    if (inChar == '\n') 
    {
        // if the incoming character is a newline, set a flag
        // so the main loop can do something about it:
        stringComplete = true;
    }
    else
    {
        // add it to the inputString:
        inputString += inChar;
    }
  }
}

[mdm]

This technique is working pretty well for me! Next step is to connect to a Pi. While I plan to measure voltage first, can you tell us off the top of your head whether the serial pins are 3.3V or 5V?

[simon_schvartzman]

Definitely 5 V.

Good luck with your project.

[Author]

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