Arduino 2.4″ Touch Screen LCD Shield Tutorial

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Overview

In this tutorial, you will learn how to use and set up 2.4″ Touch LCD Shield for Arduino. First, you’ll see some general information about this shield. And after learning how to set the shield up, you’ll see 3 practical projects.

What You Will Learn

  • View text, writing and arbitrary geometric shapes with custom colors
  • View high-quality BMP colored pictures
  • create the Paint software

Arduino 2.4 Touch screen Shield Features

The role of screens in electronic projects is very important.  Screens can be of very simple types such as 7 Segment or character LCDs or more advanced models like OLEDs and TFT LCDs.

Suggested Reading: Absolute Beginner’s Guide to TFT LCD Displays by Arduino

2.4” TFT shield is one of the most widely used graphic screens. Here are its most important features:

  • 240*320 pixels resolution
  • Ability to display 262000 different colors
  • Includes a touchpad
  • 5v supply voltage

Arduino pins 2, 3, A5, and A4 are free and you can use them to connect this shield.

Required Libraries For 2.4 Touchscreen

Adafruit GFX Library

Adafruit TouchScreen Library

Adafruit TFT LCD Library

The TFTLCD library supports 932x, 7575, 9341, and HX8357D derivers.

If your LCD does not work with this library, try the Mcufriend_kbv.

Mcufriend_kbv Library

You can apply commands to this LCD using pins A0 to A5. In case of using an SD card, all  Arduino pins will be busy.

 

Note

To display stable images, we recommend you to use an adaptor instead of the USB port.

 

How to Calibrate the Touch Screen?

One of the most important features of this LCD is including a touch panel. If you are about to use the LCD, you need to know the coordinates of the point you touch. To do so, you should upload the following code on your Arduino board and open the serial monitor. Then touch your desired location and write the coordinates displayed on the serial monitor. You can use this coordination in any other project.

/*
  TFT LCD - TFT Touch Coordinate
  Based on Librery Example
  modified on 21 Feb 2019
  by Saeed Hosseini
  https://electropeak.com/learn/
*/

#include <stdint.h>
#include "TouchScreen.h"

#define YP A2  
#define XM A3 
#define YM 8   
#define XP 9   

// For better pressure precision, we need to know the resistance
// between X+ and X- Use any multimeter to read it
// For the one we're using, its 300 ohms across the X plate
TouchScreen ts = TouchScreen(XP, YP, XM, YM, 300);

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

void loop(void) {
  
  TSPoint p = ts.getPoint();
  if (p.z > ts.pressureThreshhold) {
     Serial.print("X = "); Serial.print(p.x);
     Serial.print("\tY = "); Serial.print(p.y);
     Serial.print("\tPressure = "); Serial.println(p.z);
  }
  delay(100);
}
TSPoint p = ts.getPoint(); stores the length (x), width (y) and compression (z) in the p object.

Displaying Text and Shapes on Arduino 2.4 LCD

/*
  TFT LCD - TFT Simple driving
  modified on 21 Feb 2019
  by Saeed Hosseini
  https://electropeak.com/learn/
*/

#include <Adafruit_GFX.h>
#include <Adafruit_TFTLCD.h>

#define LCD_CS A3
#define LCD_CD A2
#define LCD_WR A1
#define LCD_RD A0
#define LCD_RESET A4

#define BLACK       0x0000
#define BLUE        0x001F
#define RED         0xF800
#define GREEN       0x07E0
#define CYAN        0x07FF
#define MAGENTA     0xF81F
#define YELLOW      0xFFE0
#define WHITE       0xFFFF
#define ORANGE      0xFD20
#define GREENYELLOW 0xAFE5
#define NAVY        0x000F
#define DARKGREEN   0x03E0
#define DARKCYAN    0x03EF
#define MAROON      0x7800
#define PURPLE      0x780F
#define OLIVE       0x7BE0
#define LIGHTGREY   0xC618
#define DARKGREY    0x7BEF

Adafruit_TFTLCD tft(LCD_CS, LCD_CD, LCD_WR, LCD_RD, LCD_RESET);

void setup() {

  Serial.begin(9600);
  Serial.println(F("TFT LCD test"));

#ifdef USE_ADAFRUIT_SHIELD_PINOUT
  Serial.println(F("Using Adafruit 2.4\" TFT Arduino Shield Pinout"));
#else
  Serial.println(F("Using Adafruit 2.4\" TFT Breakout Board Pinout"));
#endif
  Serial.print("TFT size is ");
  Serial.print(tft.width());
  Serial.print("x");
  Serial.println(tft.height());

  tft.reset();

  uint16_t identifier = tft.readID();

  if (identifier == 0x9325) {
    Serial.println(F("Found ILI9325 LCD driver"));
  } else if (identifier == 0x9328) {
    Serial.println(F("Found ILI9328 LCD driver"));
  } else if (identifier == 0x7575) {
    Serial.println(F("Found HX8347G LCD driver"));
  } else if (identifier == 0x9341) {
    Serial.println(F("Found ILI9341 LCD driver"));
  } else if (identifier == 0x8357) {
    Serial.println(F("Found HX8357D LCD driver"));
  } else {
    Serial.print(F("Unknown LCD driver chip: "));
    Serial.println(identifier, HEX);
    Serial.println(F("If using the Adafruit 2.4\" TFT Arduino shield, the line:"));
    Serial.println(F("  #define USE_ADAFRUIT_SHIELD_PINOUT"));
    Serial.println(F("should appear in the library header (Adafruit_TFT.h)."));
    Serial.println(F("If using the breakout board, it should NOT be #defined!"));
    Serial.println(F("Also if using the breakout, double-check that all wiring"));
    Serial.println(F("matches the tutorial."));
    return;
  }

  tft.begin(identifier);

  Serial.println(F("Benchmark                Time (microseconds)"));

  Serial.print(F("Screen fill              "));
  Serial.println(FillScreen());
  delay(500);

  tft.setTextColor(YELLOW);
  tft.setCursor(70, 180);
  tft.setTextSize(1);
  tft.println("Electropeak");
  delay(200);
  tft.fillScreen(PURPLE);
  tft.setCursor(50, 170);
  tft.setTextSize(2);
  tft.println("Electropeak");
  delay(200);
  tft.fillScreen(PURPLE);
  tft.setCursor(20, 160);
  tft.setTextSize(3);
  tft.println("Electropeak");
  delay(500);
  tft.fillScreen(PURPLE);
  for (int rotation = 0; rotation < 4; rotation++) { tft.setRotation(rotation); tft.setCursor(0, 0); tft.setTextSize(3); tft.println("Electropeak"); delay(700); } delay(500); Serial.print(F("Rectangles (filled) ")); Serial.println(testFilledRects(YELLOW, MAGENTA)); delay(500); } void loop() { } unsigned long FillScreen() { unsigned long start = micros(); tft.fillScreen(RED); delay(500); tft.fillScreen(GREEN); delay(500); tft.fillScreen(BLUE); delay(500); tft.fillScreen(WHITE); delay(500); tft.fillScreen(MAGENTA); delay(500); tft.fillScreen(PURPLE); delay(500); return micros() - start; } unsigned long testFilledRects(uint16_t color1, uint16_t color2) { unsigned long start, t = 0; int n, i, i2, cx = tft.width() / 2 - 1, cy = tft.height() / 2 - 1; tft.fillScreen(BLACK); n = min(tft.width(), tft.height()); for (i = n; i > 0; i -= 6) {
    i2    = i / 2;
    start = micros();
    tft.fillRect(cx - i2, cy - i2, i, i, color1);
    t    += micros() - start;
    // Outlines are not included in timing results
    tft.drawRect(cx - i2, cy - i2, i, i, color2);
  }

  return t;
}

For more information on code and functions please check Basic TFT LCD Commands.

Displaying BMP pictures

/*
 This code is TFTLCD Library Example
*/

#include <Adafruit_GFX.h>       
#include <Adafruit_TFTLCD.h>  
#include <SD.h>
#include <SPI.h>

#define LCD_CS A3 
#define LCD_CD A2 
#define LCD_WR A1 
#define LCD_RD A0 

#define SD_CS 10     

Adafruit_TFTLCD tft(LCD_CS, LCD_CD, LCD_WR, LCD_RD, A4);

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

  tft.reset();

  uint16_t identifier = tft.readID();

  if (identifier == 0x9325) {
    Serial.println(F("Found ILI9325 LCD driver"));
  } else if (identifier == 0x9328) {
    Serial.println(F("Found ILI9328 LCD driver"));
  } else if (identifier == 0x7575) {
    Serial.println(F("Found HX8347G LCD driver"));
  } else if (identifier == 0x9341) {
    Serial.println(F("Found ILI9341 LCD driver"));
  } else if (identifier == 0x8357) {
    Serial.println(F("Found HX8357D LCD driver"));
  } else {
    Serial.print(F("Unknown LCD driver chip: "));
    Serial.println(identifier, HEX);
    Serial.println(F("If using the Adafruit 2.4\" TFT Arduino shield, the line:"));
    Serial.println(F("  #define USE_ADAFRUIT_SHIELD_PINOUT"));
    Serial.println(F("should appear in the library header (Adafruit_TFT.h)."));
    Serial.println(F("If using the breakout board, it should NOT be #defined!"));
    Serial.println(F("Also if using the breakout, double-check that all wiring"));
    Serial.println(F("matches the tutorial."));
    return;
  }

  tft.begin(identifier);

  Serial.print(F("Initializing SD card..."));
  if (!SD.begin(SD_CS)) {
    Serial.println(F("failed!"));
    return;
  }
  Serial.println(F("OK!"));

  bmpDraw("pic1.bmp", 0, 0);
  delay(1000);
  bmpDraw("pic2.bmp", 0, 0);
  delay(1000);
  bmpDraw("pic3.bmp", 0, 0);
  delay(1000);
}

void loop()
{

}

#define BUFFPIXEL 20

void bmpDraw(char *filename, int x, int y) {

  File     bmpFile;
  int      bmpWidth, bmpHeight;   // W+H in pixels
  uint8_t  bmpDepth;              // Bit depth (currently must be 24)
  uint32_t bmpImageoffset;        // Start of image data in file
  uint32_t rowSize;               // Not always = bmpWidth; may have padding
  uint8_t  sdbuffer[3 * BUFFPIXEL]; // pixel in buffer (R+G+B per pixel)
  uint16_t lcdbuffer[BUFFPIXEL];  // pixel out buffer (16-bit per pixel)
  uint8_t  buffidx = sizeof(sdbuffer); // Current position in sdbuffer
  boolean  goodBmp = false;       // Set to true on valid header parse
  boolean  flip    = true;        // BMP is stored bottom-to-top
  int      w, h, row, col;
  uint8_t  r, g, b;
  uint32_t pos = 0, startTime = millis();
  uint8_t  lcdidx = 0;
  boolean  first = true;

  if ((x >= tft.width()) || (y >= tft.height())) return;

  Serial.println();
  Serial.print(F("Loading image '"));
  Serial.print(filename);
  Serial.println('\'');
  // Open requested file on SD card
  if ((bmpFile = SD.open(filename)) == NULL) {
    Serial.println(F("File not found"));
    return;
  }

  // Parse BMP header
  if (read16(bmpFile) == 0x4D42) { // BMP signature
    Serial.println(F("File size: ")); Serial.println(read32(bmpFile));
    (void)read32(bmpFile); // Read & ignore creator bytes
    bmpImageoffset = read32(bmpFile); // Start of image data
    Serial.print(F("Image Offset: ")); Serial.println(bmpImageoffset, DEC);
    // Read DIB header
    Serial.print(F("Header size: ")); Serial.println(read32(bmpFile));
    bmpWidth  = read32(bmpFile);
    bmpHeight = read32(bmpFile);
    if (read16(bmpFile) == 1) { // # planes -- must be '1'
      bmpDepth = read16(bmpFile); // bits per pixel
      Serial.print(F("Bit Depth: ")); Serial.println(bmpDepth);
      if ((bmpDepth == 24) && (read32(bmpFile) == 0)) { // 0 = uncompressed

        goodBmp = true; // Supported BMP format -- proceed!
        Serial.print(F("Image size: "));
        Serial.print(bmpWidth);
        Serial.print('x');
        Serial.println(bmpHeight);

        // BMP rows are padded (if needed) to 4-byte boundary
        rowSize = (bmpWidth * 3 + 3) & ~3;

        // If bmpHeight is negative, image is in top-down order.
        // This is not canon but has been observed in the wild.
        if (bmpHeight < 0) { bmpHeight = -bmpHeight; flip = false; } // Crop area to be loaded w = bmpWidth; h = bmpHeight; if ((x + w - 1) >= tft.width())  w = tft.width()  - x;
        if ((y + h - 1) >= tft.height()) h = tft.height() - y;

        // Set TFT address window to clipped image bounds
        tft.setAddrWindow(x, y, x + w - 1, y + h - 1);

        for (row = 0; row < h; row++) { // For each scanline...
          // Seek to start of scan line.  It might seem labor-
          // intensive to be doing this on every line, but this
          // method covers a lot of gritty details like cropping
          // and scanline padding.  Also, the seek only takes
          // place if the file position actually needs to change
          // (avoids a lot of cluster math in SD library).
          if (flip) // Bitmap is stored bottom-to-top order (normal BMP)
            pos = bmpImageoffset + (bmpHeight - 1 - row) * rowSize;
          else     // Bitmap is stored top-to-bottom
            pos = bmpImageoffset + row * rowSize;
          if (bmpFile.position() != pos) { // Need seek?
            bmpFile.seek(pos);
            buffidx = sizeof(sdbuffer); // Force buffer reload
          }

          for (col = 0; col < w; col++) { // For each column... // Time to read more pixel data? if (buffidx >= sizeof(sdbuffer)) { // Indeed
              // Push LCD buffer to the display first
              if (lcdidx > 0) {
                tft.pushColors(lcdbuffer, lcdidx, first);
                lcdidx = 0;
                first  = false;
              }
              bmpFile.read(sdbuffer, sizeof(sdbuffer));
              buffidx = 0; // Set index to beginning
            }

            // Convert pixel from BMP to TFT format
            b = sdbuffer[buffidx++];
            g = sdbuffer[buffidx++];
            r = sdbuffer[buffidx++];
            lcdbuffer[lcdidx++] = tft.color565(r, g, b);
          } // end pixel
        } // end scanline
        // Write any remaining data to LCD
        if (lcdidx > 0) {
          tft.pushColors(lcdbuffer, lcdidx, first);
        }
        Serial.print(F("Loaded in "));
        Serial.print(millis() - startTime);
        Serial.println(" ms");
      } // end goodBmp
    }
  }

  bmpFile.close();
  if (!goodBmp) Serial.println(F("BMP format not recognized."));
}

// These read 16- and 32-bit types from the SD card file.
// BMP data is stored little-endian, Arduino is little-endian too.
// May need to reverse subscript order if porting elsewhere.

uint16_t read16(File f) {
  uint16_t result;
  ((uint8_t *)&result)[0] = f.read(); // LSB
  ((uint8_t *)&result)[1] = f.read(); // MSB
  return result;
}

uint32_t read32(File f) {
  uint32_t result;
  ((uint8_t *)&result)[0] = f.read(); // LSB
  ((uint8_t *)&result)[1] = f.read();
  ((uint8_t *)&result)[2] = f.read();
  ((uint8_t *)&result)[3] = f.read(); // MSB
  return result;
}

To display pictures on this LCD you should save the picture in 24bit BMP colored format and size of 240*320. Then move them to SD card and put the SD card in the LCD shield. we use the following function to display pictures. This function has 3 arguments; the first one stands for the pictures name, and the second and third arguments are for length and width coordinates of the top left corner of the picture.

bmpdraw(“filename.bmp”,x,y);

Create A Paint App w/ Arduino 2.4 Touchscreen

/*
 This code is TFTLCD Library Example
*/

#include <Adafruit_GFX.h>        
#include <Adafruit_TFTLCD.h>  
#include <TouchScreen.h>

#if defined(__SAM3X8E__)
    #undef __FlashStringHelper::F(string_literal)
    #define F(string_literal) string_literal
#endif

#define YP A3  
#define XM A2  
#define YM 9   
#define XP 8   

#define TS_MINX 150
#define TS_MINY 120
#define TS_MAXX 920
#define TS_MAXY 940

TouchScreen ts = TouchScreen(XP, YP, XM, YM, 300);

#define LCD_CS A3
#define LCD_CD A2
#define LCD_WR A1
#define LCD_RD A0
#define LCD_RESET A4

#define  BLACK   0x0000
#define BLUE    0x001F
#define RED     0xF800
#define GREEN   0x07E0
#define CYAN    0x07FF
#define MAGENTA 0xF81F
#define YELLOW  0xFFE0
#define WHITE   0xFFFF

Adafruit_TFTLCD tft(LCD_CS, LCD_CD, LCD_WR, LCD_RD, LCD_RESET);

#define BOXSIZE 40
#define PENRADIUS 3
int oldcolor, currentcolor;

void setup(void) {
  Serial.begin(9600);
  Serial.println(F("Paint!"));
  
  tft.reset();
  
  uint16_t identifier = tft.readID();

  if(identifier == 0x9325) {
    Serial.println(F("Found ILI9325 LCD driver"));
  } else if(identifier == 0x9328) {
    Serial.println(F("Found ILI9328 LCD driver"));
  } else if(identifier == 0x7575) {
    Serial.println(F("Found HX8347G LCD driver"));
  } else if(identifier == 0x9341) {
    Serial.println(F("Found ILI9341 LCD driver"));
  } else if(identifier == 0x8357) {
    Serial.println(F("Found HX8357D LCD driver"));
  } else {
    Serial.print(F("Unknown LCD driver chip: "));
    Serial.println(identifier, HEX);
    Serial.println(F("If using the Adafruit 2.4\" TFT Arduino shield, the line:"));
    Serial.println(F("  #define USE_ADAFRUIT_SHIELD_PINOUT"));
    Serial.println(F("should appear in the library header (Adafruit_TFT.h)."));
    Serial.println(F("If using the breakout board, it should NOT be #defined!"));
    Serial.println(F("Also if using the breakout, double-check that all wiring"));
    Serial.println(F("matches the tutorial."));
    return;
  }

  tft.begin(identifier);

  tft.fillScreen(BLACK);

  tft.fillRect(0, 0, BOXSIZE, BOXSIZE, RED);
  tft.fillRect(BOXSIZE, 0, BOXSIZE, BOXSIZE, YELLOW);
  tft.fillRect(BOXSIZE*2, 0, BOXSIZE, BOXSIZE, GREEN);
  tft.fillRect(BOXSIZE*3, 0, BOXSIZE, BOXSIZE, CYAN);
  tft.fillRect(BOXSIZE*4, 0, BOXSIZE, BOXSIZE, BLUE);
  tft.fillRect(BOXSIZE*5, 0, BOXSIZE, BOXSIZE, MAGENTA);
 
  tft.drawRect(0, 0, BOXSIZE, BOXSIZE, WHITE);
  currentcolor = RED;
 
  pinMode(13, OUTPUT);
}

#define MINPRESSURE 10
#define MAXPRESSURE 1000

void loop()
{
  digitalWrite(13, HIGH);
  TSPoint p = ts.getPoint();
  digitalWrite(13, LOW);


  pinMode(XM, OUTPUT);
  pinMode(YP, OUTPUT);

  if (p.z > MINPRESSURE && p.z < MAXPRESSURE) {

    
    if (p.y < (TS_MINY-5)) {
      Serial.println("erase");

      tft.fillRect(0, BOXSIZE, tft.width(), tft.height()-BOXSIZE, BLACK);
    }

    p.x = map(p.x, TS_MINX, TS_MAXX, tft.width(), 0);
    p.y = map(p.y, TS_MINY, TS_MAXY, tft.height(), 0);

    if (p.y < BOXSIZE) {
       oldcolor = currentcolor;

       if (p.x < BOXSIZE) { 
         currentcolor = RED; 
         tft.drawRect(0, 0, BOXSIZE, BOXSIZE, WHITE);
       } else if (p.x < BOXSIZE*2) {
         currentcolor = YELLOW;
         tft.drawRect(BOXSIZE, 0, BOXSIZE, BOXSIZE, WHITE);
       } else if (p.x < BOXSIZE*3) {
         currentcolor = GREEN;
         tft.drawRect(BOXSIZE*2, 0, BOXSIZE, BOXSIZE, WHITE);
       } else if (p.x < BOXSIZE*4) {
         currentcolor = CYAN;
         tft.drawRect(BOXSIZE*3, 0, BOXSIZE, BOXSIZE, WHITE);
       } else if (p.x < BOXSIZE*5) {
         currentcolor = BLUE;
         tft.drawRect(BOXSIZE*4, 0, BOXSIZE, BOXSIZE, WHITE);
       } else if (p.x < BOXSIZE*6) { currentcolor = MAGENTA; tft.drawRect(BOXSIZE*5, 0, BOXSIZE, BOXSIZE, WHITE); } if (oldcolor != currentcolor) { if (oldcolor == RED) tft.fillRect(0, 0, BOXSIZE, BOXSIZE, RED); if (oldcolor == YELLOW) tft.fillRect(BOXSIZE, 0, BOXSIZE, BOXSIZE, YELLOW); if (oldcolor == GREEN) tft.fillRect(BOXSIZE*2, 0, BOXSIZE, BOXSIZE, GREEN); if (oldcolor == CYAN) tft.fillRect(BOXSIZE*3, 0, BOXSIZE, BOXSIZE, CYAN); if (oldcolor == BLUE) tft.fillRect(BOXSIZE*4, 0, BOXSIZE, BOXSIZE, BLUE); if (oldcolor == MAGENTA) tft.fillRect(BOXSIZE*5, 0, BOXSIZE, BOXSIZE, MAGENTA); } } if (((p.y-PENRADIUS) > BOXSIZE) && ((p.y+PENRADIUS) < tft.height())) {
      tft.fillCircle(p.x, p.y, PENRADIUS, currentcolor);
    }
  }
}

Final Notes

  • If you want to display pictures without using an SD card, you can convert it to code and then display it. You can display even several photos sequentially without delay to create an animation. (Check this) But be aware that in this case, Arduino UNO may not be suitable (because of low processor speed). We recommend using the Arduino Mega or Arduino DUE.
  • When purchasing this LCD, make sure that drivers are supported by the libraries listed.

Buy 2.4 TFT LCD Display Shield

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