arduino lcd touch screen tutorial free sample

In this Arduino touch screen tutorial we will learn how to use TFT LCD Touch Screen with Arduino. You can watch the following video or read the written tutorial below.

For this tutorial I composed three examples. The first example is distance measurement using ultrasonic sensor. The output from the sensor, or the distance is printed on the screen and using the touch screen we can select the units, either centimeters or inches.

The third example is a game. Actually it’s a replica of the popular Flappy Bird game for smartphones. We can play the game using the push button or even using the touch screen itself.

As an example I am using a 3.2” TFT Touch Screen in a combination with a TFT LCD Arduino Mega Shield. We need a shield because the TFT Touch screen works at 3.3V and the Arduino Mega outputs are 5 V. For the first example I have the HC-SR04 ultrasonic sensor, then for the second example an RGB LED with three resistors and a push button for the game example. Also I had to make a custom made pin header like this, by soldering pin headers and bend on of them so I could insert them in between the Arduino Board and the TFT Shield.

Here’s the circuit schematic. We will use the GND pin, the digital pins from 8 to 13, as well as the pin number 14. As the 5V pins are already used by the TFT Screen I will use the pin number 13 as VCC, by setting it right away high in the setup section of code.

I will use the UTFT and URTouch libraries made by Henning Karlsen. Here I would like to say thanks to him for the incredible work he has done. The libraries enable really easy use of the TFT Screens, and they work with many different TFT screens sizes, shields and controllers. You can download these libraries from his website, RinkyDinkElectronics.com and also find a lot of demo examples and detailed documentation of how to use them.

After we include the libraries we need to create UTFT and URTouch objects. The parameters of these objects depends on the model of the TFT Screen and Shield and these details can be also found in the documentation of the libraries.

Next we need to define the fonts that are coming with the libraries and also define some variables needed for the program. In the setup section we need to initiate the screen and the touch, define the pin modes for the connected sensor, the led and the button, and initially call the drawHomeSreen() custom function, which will draw the home screen of the program.

So now I will explain how we can make the home screen of the program. With the setBackColor() function we need to set the background color of the text, black one in our case. Then we need to set the color to white, set the big font and using the print() function, we will print the string “Arduino TFT Tutorial” at the center of the screen and 10 pixels  down the Y – Axis of the screen. Next we will set the color to red and draw the red line below the text. After that we need to set the color back to white, and print the two other strings, “by HowToMechatronics.com” using the small font and “Select Example” using the big font.

Now we need to make the buttons functional so that when we press them they would send us to the appropriate example. In the setup section we set the character ‘0’ to the currentPage variable, which will indicate that we are at the home screen. So if that’s true, and if we press on the screen this if statement would become true and using these lines here we will get the X and Y coordinates where the screen has been pressed. If that’s the area that covers the first button we will call the drawDistanceSensor() custom function which will activate the distance sensor example. Also we will set the character ‘1’ to the variable currentPage which will indicate that we are at the first example. The drawFrame() custom function is used for highlighting the button when it’s pressed. The same procedure goes for the two other buttons.

So the drawDistanceSensor() custom function needs to be called only once when the button is pressed in order to draw all the graphics of this example in similar way as we described for the home screen. However, the getDistance() custom function needs to be called repeatedly in order to print the latest results of the distance measured by the sensor.

Here’s that function which uses the ultrasonic sensor to calculate the distance and print the values with SevenSegNum font in green color, either in centimeters or inches. If you need more details how the ultrasonic sensor works you can check my particular tutorialfor that. Back in the loop section we can see what happens when we press the select unit buttons as well as the back button.

Ok next is the RGB LED Control example. If we press the second button, the drawLedControl() custom function will be called only once for drawing the graphic of that example and the setLedColor() custom function will be repeatedly called. In this function we use the touch screen to set the values of the 3 sliders from 0 to 255. With the if statements we confine the area of each slider and get the X value of the slider. So the values of the X coordinate of each slider are from 38 to 310 pixels and we need to map these values into values from 0 to 255 which will be used as a PWM signal for lighting up the LED. If you need more details how the RGB LED works you can check my particular tutorialfor that. The rest of the code in this custom function is for drawing the sliders. Back in the loop section we only have the back button which also turns off the LED when pressed.

In order the code to work and compile you will have to include an addition “.c” file in the same directory with the Arduino sketch. This file is for the third game example and it’s a bitmap of the bird. For more details how this part of the code work  you can check my particular tutorial. Here you can download that file:

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.

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.

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.

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.

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.

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.

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.

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 CoordinateBased on Librery Examplemodified on 21 Feb 2019by Saeed Hosseinihttps://electropeak.com/learn/*/#include #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 plateTouchScreen 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);}

Displaying Text and Shapes on Arduino 2.4 LCD/*TFT LCD - TFT Simple drivingmodified on 21 Feb 2019by Saeed Hosseinihttps://electropeak.com/learn/*/#include #include #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 0x7BEFAdafruit_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_PINOUTSerial.println(F("Using Adafruit 2.4\" TFT Arduino Shield Pinout"));#elseSerial.println(F("Using Adafruit 2.4\" TFT Breakout Board Pinout"));#endifSerial.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 resultstft.drawRect(cx - i2, cy - i2, i, i, color2);}return t;}

Displaying BMP pictures/*This code is TFTLCD Library Example*/#include #include #include #include #define LCD_CS A3#define LCD_CD A2#define LCD_WR A1#define LCD_RD A0#define SD_CS 10Adafruit_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 20void bmpDraw(char *filename, int x, int y) {File bmpFile;int bmpWidth, bmpHeight; // W+H in pixelsuint8_t bmpDepth; // Bit depth (currently must be 24)uint32_t bmpImageoffset; // Start of image data in fileuint32_t rowSize; // Not always = bmpWidth; may have paddinguint8_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 sdbufferboolean goodBmp = false; // Set to true on valid header parseboolean flip = true; // BMP is stored bottom-to-topint 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 cardif ((bmpFile = SD.open(filename)) == NULL) {Serial.println(F("File not found"));return;}// Parse BMP headerif (read16(bmpFile) == 0x4D42) { // BMP signatureSerial.println(F("File size: ")); Serial.println(read32(bmpFile));(void)read32(bmpFile); // Read & ignore creator bytesbmpImageoffset = read32(bmpFile); // Start of image dataSerial.print(F("Image Offset: ")); Serial.println(bmpImageoffset, DEC);// Read DIB headerSerial.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 pixelSerial.print(F("Bit Depth: ")); Serial.println(bmpDepth);if ((bmpDepth == 24) && (read32(bmpFile) == 0)) { // 0 = uncompressedgoodBmp = 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 boundaryrowSize = (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 boundstft.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-bottompos = 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 firstif (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 formatb = sdbuffer[buffidx++];g = sdbuffer[buffidx++];r = sdbuffer[buffidx++];lcdbuffer[lcdidx++] = tft.color565(r, g, b);} // end pixel} // end scanline// Write any remaining data to LCDif (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(); // MSBreturn 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(); // MSBreturn 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 #include #include #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 940TouchScreen 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 0xFFFFAdafruit_TFTLCD tft(LCD_CS, LCD_CD, LCD_WR, LCD_RD, LCD_RESET);#define BOXSIZE 40#define PENRADIUS 3int 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 1000void 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 NotesIf 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.

Spice up your Arduino project with a beautiful large touchscreen display shield with built in microSD card connection. This TFT display is big (5" diagonal) bright (18 white-LED backlight) and colorful 800x480 pixels with individual pixel control. As a bonus, this display has a capacitive touch panel attached on screen by default.

The shield is fully assembled, tested and ready to go. No wiring, no soldering! Simply plug it in and load up our library - you"ll have it running in under 10 minutes! Works best with any classic Arduino Mega2560.

Of course, we wouldn"t just leave you with a datasheet and a "good luck!" - we"ve written a full open source graphics library at the bottom of this page that can draw pixels, lines, rectangles, circles and text. We also have a touch screen library that detects x,y and z (pressure) and example code to demonstrate all of it. The code is written for Arduino but can be easily ported to your favorite microcontroller!

If you"ve had a lot of Arduino DUEs go through your hands (or if you are just unlucky), chances are you’ve come across at least one that does not start-up properly.The symptom is simple: you power up the Arduino but it doesn’t appear to “boot”. Your code simply doesn"t start running.You might have noticed that resetting the board (by pressing the reset button) causes the board to start-up normally.The fix is simple,here is the solution.

The AZ-Delivery 2.4” TFT LCD Touch Display boasts 320x 240 pixels with 16-bit color. It has Touch capabilities, a built-in SD card drive, and plugs straight onto the top of an Arduino UNO or Mega. Amazon charges less than £11 for this device. It offers a major step up from the tiny SSD1306 128×64 monochrome display.

The TFT screen is much larger than the SSD1306 128×64 and much more colourful. The package includes an SD card reader on the underside and a stylus for accurate touch-screen control.

The underside of the board has labels on the pins. As the board is an Arduino shield, it will only fit on a UNO in one position. The SD card reader sits between USB and the power socket. It will also plug into and Arduino MEGA 2560. J1 and J2 fit into the digital pins, covering D0 to D13, while J3 and J4 fit into the analog and power pins.

I searched the Web for drivers and examples and found a great deal of praise for the TFT graphics, reports of problems with the Touch control and nothing about the SD card reader on this board.

In the end I installed several libraries (with all dependencies): Adafruit GFX, Adafruit TFTLCD, Adafruit TouchScreen, Adafruit ILI9341, MCUFRIEND_kbv and SPFD5408-master. (The last 2 are not essential but include some interesting examples). The SD library is included in the basic Arduino set.

I’ve used GFX with mono displays such as SSD1306 and soon got the TFT display working. The following script gives some idea about what it can do. I’ve included pixels, text (of varying sizes), lines, rectangles, triangles, squares, graphs, screen rotation, and text on a path. I was very impressed with the clarity, speed, brightness, and colors produced.

Normally, when setting the colour of an RGB LED you have a range of 0-255 (0-FF hex) for each RGB component which gives white = FFFFFF, red = FF000, green FF00 and blue = FF. This is 24-bit colour and takes 3 bytes.  224 gives 16,777,216 different colours. The TFT screen is a 16-bit colour device which can display 65,536 different colours – more than enough. Here the range is limited to 5 bits each for red and blue and 6 bits for green. (Our eyes are more sensitive to green so It gets the extra bit of accuracy.)

The following sketch gives an indication of the colours available by converting an array of 24-bit colour values into their 16-bit equivalent and displaying them on the screen with the data. There are not enough pixels on the screen to display all the colours at once so the last part of the sketch takes out the least significant green bit and displays half the available colours six ways.

Most Arduino users seldom use string manipulation. The documentation and a few simple examples of how to use strings are well scattered over the Web and difficult to find. The first sketch demonstrates how to create a file of 5 records/lines, each made up from an integer, a string, and a floating-point variable. The file is called datalog6.txt.

This is the part that often causes the most trouble with many owners giving up at this point. It may be because there are several different configurations of the pins used to connect to the touch layers of the screen on the many varied breakout boards and shields using this display. In this case four of the pins are used, at different times, to control both the graphics or the touch elements of the screen.

This is a resistive touch screen, rather than a capacitive one. Above the graphics, layers are two transparent resistive layers held apart by tiny dimples. One is connected at the top and bottom and the other at the sides. A potential difference is applied across them and when the stylus or a finger presses on the screen an electrical connection is made between the resistive layers.

The Analog pins are used to measure the voltages at that point on the two resistive layers, one at a time, in the same manner as we read the voltage from the wiper of a potentiometer – a potential divider. Using these values, it is possible to calculate, quite accurately, the coordinates of the point on the screen where the pressure has been applied. Calibration is often needed to improve accuracy. Adafruit suggests reading the resistance across the X plate (XP = D8 and XM = A2). On my board, I got 341 Ohms. Use this value as SENSITIVITY.

Try running the sketch to draw on the screen. The BLACK palette ‘button’ clears the screen and the others change the ‘ink’ colour. If the dot drawn is not directly under the stylus you can adjust the ‘fudge factors’ in the scaling section.

As a final example here is a sketch which shows off the Touch screen with buttons, bar graphs and colours. The buttons allow the user to adjust the RGB mix to display all the possible colours available. If you find one you particularly like it displays the hex value of the 16-bit colour.

There is a small amount of jitter as the bar graph re-draws but overall, the shield works quickly and very well. After the screen has updated and waiting for a touch the image is steady, sharp, and bright. Once you have calibrated the touch device it is very accurate as demonstrated with the small (30×30 pixel buttons) and provides excellent, colorful graphics on a usefully large display.

I was very pleased with the quality of the display and the accuracy of the Touch device. It sits neatly and securely on a UNO or a MEGA 2560. With an SD card reader included it was excellent value and I will be making good use of it in the future.

Arduino has always helped to build projects easily and make them look more attractive.  Programming an LCD screen with touch screen option might sound as a complicated task, but the Arduino libraries and shields had made it really easy. In this project we will use a 2.4” Arduino TFT LCD screen to build our own Arduino Touch Screen calculator that could perform all basic calculations like Addition, Subtraction, Division and Multiplication.

Before we actually dive into the project it is important to know, how this 2.4” TFT LCD Module works and what are the types present in it. Let us take a look at the pinouts of this 2.4” TFT LCD screen module.

As you can see there are 28 pins which will perfectly fit into any Arduino Uno / Arduino Mega Board. A small classification of these pins is given in the table below.

As you can see the pins can be classified in to four main classifications such as LCD Command Pins, LCD Data Pins, SD Card Pins and Power Pins, We need not know much about the detailed working of these pins since they will be take care by our Arduino Library.

You can also find an SD card slot at the bottom of the module shown above, which can be used to load an SD card with bmp image files, and these images can be displayed in our TFT LCD screen using the Arduino Program.

Another important thing to note is your Interface IC. There are many types of TFT modules available in the market starting from the original Adafruit TFT LCD module to cheap Chinese clones. A program which works perfectly for your Adafruit shield might not work the same for Chinese breakout boards. So, it is very important to know which types of LCD display your are holding in hand. This detail has to be obtained from the vendor. If you are having a cheap clone like mine then it is most probably using the ili9341 driver IC.You can follow this TFT LCD interfacing with Arduino tutorial to try out some basic example programs and get comfortable with the LCD screen. Also check out our other TFT LCD projects with Arduino here:

If you planning to use the touch screen function of your TFT LCD module, then you have to calibrate it to make it work properly.  A LCD screen without calibration might work unlikely, for instance you might touch at one place and the TFT might respond for a touch at some other place. These calibrations results will not be similar for all boards and hence you are left on your own to do this.

The best way to calibrate is to use the calibration example program (comes with library) or use the serial monitor to detect your error.  However for this project since the size of buttons is large calibration should not be a big problem and I will also explain how you can calibrate your screen under the programming section below.

The 2.4” TFT LCD screen is a perfect Arduino Shield. You can directly push the LCD screen on top of the Arduino Uno and it will perfectly match with the pins and slid in through. However, as matters of safety cover the Programming terminal of your Arduino UNO with a small insulation tape, just in case if the terminal comes in contact with your TFT LCD screen. The LCD assembled on UNO will look something like this below.

We are using the SPFD5408 Library to get this arduino calculator code working. This is a modified library of Adafruit and can work seamlessly with our LCD TFT Module. You can check the complete program at the end of this Article.

Now, open Arduino IDE and select Sketch -> Include Librarey -> Add .ZIP library. A browser window will open navigate to the ZIP file and click “OK”. You should notice “Library added to your Libraries” on the bottom-left corner of Arduino, if successful. A detailed guide to do the same is given in the Interfacing Tutorial.

Now, you can use the code below in your Arduino IDE and upload it to your Arduino UNO for the Touch Screen Calculator to work. Further down, I have explained the code into small segments.

As said earlier we need to calibrate the LCD screen to make it work as expected, but don’t worry the values given here are almost universal. The variables TS_MINX, TS_MINY, TS_MAXX, and TS_MAXY decide the calibration of the Screen. You can toy around them if you feel the calibration is not satisfactory.

As we know the TFT LCD screen can display a lot of colours, all these colours have to be entered in hex value. To make it more human readable we assign these values to a variable as shown below.

Okay now, we can get into the programming part. There are three sections involved in this program. One is creating a UI of a calculator with buttons and display. Then, detecting the buttons based on the users touch and finally calculating the results and display them. Let us get through them one by one.

Another challenging task is detecting the user touch. Every time the user touches somewhere we will able to how where the X and Y position of the pixel he touched. This value can be displayed on the serial monitor using the println as shown below.

Now, since we know the position of all the boxes. When a user touches anywhere we can predict where he has touched by comparing his (X,Y) values with the value for each box as shown below.

The final step is to calculate the result and display them on TFT LCD Screen. This arduino calculator can perform operation with 2 numbers only. These two numbers are named as variables “Num1” and “Num2”. The variable “Number” gives and takes value from Num1 and Num2 and also bears the result.

The working of this Arduino Touch Screen Calculator is simple. You have to upload the below given code on your Arduino and fire it up. You get the calculator displayed on your LCD screen.

You have to press the “C” to clear the value on screen each time after performing a calculation. Hope you understood the project and enjoyed building something similar. If you have any doubts feel free to post them on forums or on the comment section below. See you next time with another interesting project until then happy computing!!

In this article, you will learn how to use TFT LCDs by Arduino boards. From basic commands to professional designs and technics are all explained here.

There are several components to achieve this. LEDs,  7-segments, Character and Graphic displays, and full-color TFT LCDs. The right component for your projects depends on the amount of data to be displayed, type of user interaction, and processor capacity.

TFT LCD is a variant of a liquid-crystal display (LCD) that uses thin-film-transistor (TFT) technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven LCDs with a few segments.

In Arduino-based projects, the processor frequency is low. So it is not possible to display complex, high definition images and high-speed motions. Therefore, full-color TFT LCDs can only be used to display simple data and commands.

There are several components to achieve this. LEDs,  7-segments, Character and Graphic displays, and full-color TFT LCDs. The right component for your projects depends on the amount of data to be displayed, type of user interaction, and processor capacity.

TFT LCD is a variant of a liquid-crystal display (LCD) that uses thin-film-transistor (TFT) technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven LCDs with a few segments.

In Arduino-based projects, the processor frequency is low. So it is not possible to display complex, high definition images and high-speed motions. Therefore, full-color TFT LCDs can only be used to display simple data and commands.

After choosing the right display, It’s time to choose the right controller. If you want to display characters, tests, numbers and static images and the speed of display is not important, the Atmega328 Arduino boards (such as Arduino UNO) are a proper choice. If the size of your code is big, The UNO board may not be enough. You can use Arduino Mega2560 instead. And if you want to show high resolution images and motions with high speed, you should use the ARM core Arduino boards such as Arduino DUE.

In electronics/computer hardware a display driver is usually a semiconductor integrated circuit (but may alternatively comprise a state machine made of discrete logic and other components) which provides an interface function between a microprocessor, microcontroller, ASIC or general-purpose peripheral interface and a particular type of display device, e.g. LCD, LED, OLED, ePaper, CRT, Vacuum fluorescent or Nixie.

The LCDs manufacturers use different drivers in their products. Some of them are more popular and some of them are very unknown. To run your display easily, you should use Arduino LCDs libraries and add them to your code. Otherwise running the display may be very difficult. There are many free libraries you can find on the internet but the important point about the libraries is their compatibility with the LCD’s driver. The driver of your LCD must be known by your library. In this article, we use the Adafruit GFX library and MCUFRIEND KBV library and example codes. You can download them from the following links.

You must add the library and then upload the code. If it is the first time you run an Arduino board, don’t worry. Just follow these steps:Go to www.arduino.cc/en/Main/Software and download the software of your OS. Install the IDE software as instructed.

First you should convert your image to hex code. Download the software from the following link. if you don’t want to change the settings of the software, you must invert the color of the image and make the image horizontally mirrored and rotate it 90 degrees counterclockwise. Now add it to the software and convert it. Open the exported file and copy the hex code to Arduino IDE. x and y are locations of the image. sx and sy are sizes of image. you can change the color of the image in the last input.

Upload your image and download the converted file that the UTFT libraries can process. Now copy the hex code to Arduino IDE. x and y are locations of the image. sx and sy are size of the image.

In this template, We converted a .jpg image to .c file and added to the code, wrote a string and used the fade code to display. Then we used scroll code to move the screen left. Download the .h file and add it to the folder of the Arduino sketch.

In this template, We used sin(); and cos(); functions to draw Arcs with our desired thickness and displayed number by text printing function. Then we converted an image to hex code and added them to the code and displayed the image by bitmap function. Then we used draw lines function to change the style of the image. Download the .h file and add it to the folder of the Arduino sketch.

In this template, We added a converted image to code and then used two black and white arcs to create the pointer of volumes.  Download the .h file and add it to the folder of the Arduino sketch.

In this template, We added a converted image and use the arc and print function to create this gauge.  Download the .h file and add it to folder of the Arduino sketch.

In this template, We display simple images one after each other very fast by bitmap function. So you can make your animation by this trick.  Download the .h file and add it to folder of the Arduino sketch.

In this template, We just display some images by RGBbitmap and bitmap functions. Just make a code for touchscreen and use this template.  Download the .h file and add it to folder of the Arduino sketch.

Hey guys, its Nick again, welcome to educ8s.tv a channel that is all about DIY electronics projects with Arduino, Raspberry Pi, ESP8266 and other popular boards. Today we are going to take a look at how to use the inexpensive, ILI9325 driver based, 2.8” touchscreen display designed for Arduino and at the end of this tutorial, you should be able to determine ifthis Touch Screen is a good option for your Arduino projects.

I first came across this touchscreen which offers a resolution of 320×240 pixels, and an easy to use micro SD slot among several other great features on banggood.com and decided to buy it for use in some of my projects since it was inexpensive as it only costs around $11.

As shown in the video above, we will be performing simple tasks with the display to demonstrate how it works such that, When we press a button on the screen, a message will be displayed it. This means we will learn both how to create a button on the screen such that it can be touched and how to display messages on the screen.

As demonstrated the touch screen is working fine! Finally, we can start building projects with a touch screen which are much more interesting and easier to use.

The display comes as a shield which makes the connection with Arduino extremely easy, thus all that needs to be done for this project is to plug the display into the Arduino board since we won’t be adding any other sensor or actuator.

One of the few downsides to this display is that it uses almost all of the digital and analog pins of the Arduino Uno which means when using this shield, we are left with only 2 digital pins and 1 analog pin for connections to other components that the project we are building might require.

Fortunately, this display works fine with the Arduino Mega, so when working on projects with more pin requirements and size is not really an issue, we can use the Arduino Mega instead of the Arduino Uno. Unfortunately, this display does not work with some other Arduino Uno form factor based boards like the Arduino Due or the Wemos D1 ESP8266 board due to pin compatibility and library Issues.

In order to use this Arduino Touch Screen easily, we will need three libraries. We will need a modified version of the Adafruit TFTLCD library, the familiar Adafruit GFX library, and the Touchscreen library. All these libraries can be downloaded by following the links below.

With the Libraries installed, we can test the display by trying out the examples which came with the libraries. Two favorite examples are the graphicstext example and the tftbmp example whose demonstration can be seen in the tutorial video.

To explore the Touchscreen functionality of the display, I have developed a sample code, which you can extend for use in any of your projects. it can be downloaded via the download link below.

To use the touchscreen functionality of this display, there is a need for the display to be calibrated. To do this after uploading the code, Open the Serial Monitor and click (touch) on the top left corner of the display and write down the X and Y values displayed on the serial monitor. Then we edit the code to reflect those values. The X value goes to the TS_MAXX variable and the Y value goes to the TS_MAXY variable. We follow the same procedure for the other two variables. We click on the bottom right corner of the display and we enter the values we get in the TS_MINX and TS_MINY variables. With this done our display is now calibrated and ready for use.

Next, we declare the colors to be used with their hexadecimal values after which we create an object of the Adafruit TFTLCD library class indicating the variables used to represent the pins to which the screen is connected on the Arduino.

We start the function by initializing the serial monitor and the LCD, after which we set the orientation of the LCD and fill the screen with a black color to serve as the background.

Next, we draw a white frame on the display then set the cursor to the desired location, change the text color to white, and print the “Hello” text on the screen. By following the same procedure, we display the red YouTube text as well.

With the setup function all done, we move to the loop function, the algorithm in operation for the loop section is simple, each time the user clicks on the screen, we convert the point coordinates of the touch point into pixels using the Map function. After conversion, If that point is inside the red rectangle area, it means that the user has pressed the button, so we disable the button by setting this variable to false and we clear the screen so as to display the “thank you for subscribing” message on the screen.

That’s it for today’s tutorial guys, thanks for reading/watching. If you get stuck at any point while building this project, feel free to reach out to me via the comment section, I will be glad to answer whatever questions you might have. Don’t forget to share, like and subscribe on youtube. Thanks!

In this guide we’re going to show you how you can use the 1.8 TFT display with the Arduino. You’ll learn how to wire the display, write text, draw shapes and display images on the screen.

The 1.8 TFT is a colorful display with 128 x 160 color pixels. The display can load images from an SD card – it has an SD card slot at the back. The following figure shows the screen front and back view.

This module uses SPI communication – see the wiring below . To control the display we’ll use the TFT library, which is already included with Arduino IDE 1.0.5 and later.

The TFT display communicates with the Arduino via SPI communication, so you need to include the SPI library on your code. We also use the TFT library to write and draw on the display.

In which “Hello, World!” is the text you want to display and the (x, y) coordinate is the location where you want to start display text on the screen.

The 1.8 TFT display can load images from the SD card. To read from the SD card you use the SD library, already included in the Arduino IDE software. Follow the next steps to display an image on the display:

In this guide we’ve shown you how to use the 1.8 TFT display with the Arduino: display text, draw shapes and display images. You can easily add a nice visual interface to your projects using this display.

In this tutorial, I’ll explain how to set up an LCD on an Arduino and show you all the different ways you can program it. I’ll show you how to print text, scroll text, make custom characters, blink text, and position text. They’re great for any project that outputs data, and they can make your project a lot more interesting and interactive.

The display I’m using is a 16×2 LCD display that I bought for about $5. You may be wondering why it’s called a 16×2 LCD. The part 16×2 means that the LCD has 2 lines, and can display 16 characters per line. Therefore, a 16×2 LCD screen can display up to 32 characters at once. It is possible to display more than 32 characters with scrolling though.

The code in this article is written for LCD’s that use the standard Hitachi HD44780 driver. If your LCD has 16 pins, then it probably has the Hitachi HD44780 driver. These displays can be wired in either 4 bit mode or 8 bit mode. Wiring the LCD in 4 bit mode is usually preferred since it uses four less wires than 8 bit mode. In practice, there isn’t a noticeable difference in performance between the two modes. In this tutorial, I’ll connect the LCD in 4 bit mode.

BONUS: I made a quick start guide for this tutorial that you can download and go back to later if you can’t set this up right now. It covers all of the steps, diagrams, and code you need to get started.

The 3-in-1 Smart Car and IOT Learning Kit from SunFounder has everything you need to learn how to master the Arduino. It includes all of the parts, wiring diagrams, code, and step-by-step instructions for 58 different robotics and internet of things projects that are super fun to build!

Here’s a diagram of the pins on the LCD I’m using. The connections from each pin to the Arduino will be the same, but your pins might be arranged differently on the LCD. Be sure to check the datasheet or look for labels on your particular LCD:

Also, you might need to solder a 16 pin header to your LCD before connecting it to a breadboard. Follow the diagram below to wire the LCD to your Arduino:

All of the code below uses the LiquidCrystal library that comes pre-installed with the Arduino IDE. A library is a set of functions that can be easily added to a program in an abbreviated format.

In order to use a library, it needs be included in the program. Line 1 in the code below does this with the command #include . When you include a library in a program, all of the code in the library gets uploaded to the Arduino along with the code for your program.

Now we’re ready to get into the programming! I’ll go over more interesting things you can do in a moment, but for now lets just run a simple test program. This program will print “hello, world!” to the screen. Enter this code into the Arduino IDE and upload it to the board:

There are 19 different functions in the LiquidCrystal library available for us to use. These functions do things like change the position of the text, move text across the screen, or make the display turn on or off. What follows is a short description of each function, and how to use it in a program.

TheLiquidCrystal() function sets the pins the Arduino uses to connect to the LCD. You can use any of the Arduino’s digital pins to control the LCD. Just put the Arduino pin numbers inside the parentheses in this order:

This function sets the dimensions of the LCD. It needs to be placed before any other LiquidCrystal function in the void setup() section of the program. The number of rows and columns are specified as lcd.begin(columns, rows). For a 16×2 LCD, you would use lcd.begin(16, 2), and for a 20×4 LCD you would use lcd.begin(20, 4).

This function clears any text or data already displayed on the LCD. If you use lcd.clear() with lcd.print() and the delay() function in the void loop() section, you can make a simple blinking text program:

This function places the cursor in the upper left hand corner of the screen, and prints any subsequent text from that position. For example, this code replaces the first three letters of “hello world!” with X’s:

Similar, but more useful than lcd.home() is lcd.setCursor(). This function places the cursor (and any printed text) at any position on the screen. It can be used in the void setup() or void loop() section of your program.

The cursor position is defined with lcd.setCursor(column, row). The column and row coordinates start from zero (0-15 and 0-1 respectively). For example, using lcd.setCursor(2, 1) in the void setup() section of the “hello, world!” program above prints “hello, world!” to the lower line and shifts it to the right two spaces:

You can use this function to write different types of data to the LCD, for example the reading from a temperature sensor, or the coordinates from a GPS module. You can also use it to print custom characters that you create yourself (more on this below). Use lcd.write() in the void setup() or void loop() section of your program.

The function lcd.noCursor() turns the cursor off. lcd.cursor() and lcd.noCursor() can be used together in the void loop() section to make a blinking cursor similar to what you see in many text input fields:

Cursors can be placed anywhere on the screen with the lcd.setCursor() function. This code places a blinking cursor directly below the exclamation point in “hello, world!”:

This function creates a block style cursor that blinks on and off at approximately 500 milliseconds per cycle. Use it in the void loop() section. The function lcd.noBlink() disables the blinking block cursor.

This function turns on any text or cursors that have been printed to the LCD screen. The function lcd.noDisplay() turns off any text or cursors printed to the LCD, without clearing it from the LCD’s memory.

This function takes anything printed to the LCD and moves it to the left. It should be used in the void loop() section with a delay command following it. The function will move the text 40 spaces to the left before it loops back to the first character. This code moves the “hello, world!” text to the left, at a rate of one second per character:

Like the lcd.scrollDisplay() functions, the text can be up to 40 characters in length before repeating. At first glance, this function seems less useful than the lcd.scrollDisplay() functions, but it can be very useful for creating animations with custom characters.

lcd.noAutoscroll() turns the lcd.autoscroll() function off. Use this function before or after lcd.autoscroll() in the void loop() section to create sequences of scrolling text or animations.

This function sets the direction that text is printed to the screen. The default mode is from left to right using the command lcd.leftToRight(), but you may find some cases where it’s useful to output text in the reverse direction:

This code prints the “hello, world!” text as “!dlrow ,olleh”. Unless you specify the placement of the cursor with lcd.setCursor(), the text will print from the (0, 1) position and only the first character of the string will be visible.

This command allows you to create your own custom characters. Each character of a 16×2 LCD has a 5 pixel width and an 8 pixel height. Up to 8 different custom characters can be defined in a single program. To design your own characters, you’ll need to make a binary matrix of your custom character from an LCD character generator or map it yourself. This code creates a degree symbol (°):

Touchscreen displays are everywhere! Phones, tablets, self-serve kiosks, bank machines and thousands of other devices we interact with make use of touchscreen displays to provide an intuitive user interface.

Today we will learn how touchscreens work, and how to use a common inexpensive resistive touchscreen shield for the Arduino.  Future videos and articles will cover capacitive touchscreens, as well as a touchscreen HAT for the Raspberry Pi.

Although touchscreens seem to be everywhere these days we tend to forget that just a few decades ago these devices were just science fiction for most of us. For many people, the touchscreen concept was introduced 30 years ago in the television seriesStar Trek: The Next Generation.

Eric A Johnson, a researcher at the Royal Radar Establishment in Malvern UK is credited for describing and then prototyping the first practical touchscreen. HIs device was a capacitive touchscreen, and it’s first commercial use was on air traffic control screens. However, the touchscreens used then were not transparent, instead, they were mounted on the frame of the CRT display.

In 1972, a group at the University of Illinois filed for a patent on an optical touchscreen. This device used a 16×16 array of LEDs and phototransistors, mounted on a frame around a CRT display. Placing your finger, or another solid object, on the screen would break two of the light beams, this was used to determine the position and respond accordingly.

The first transparent touchscreen was developed atCERNin 1973. CERN is also home to the Large Hadron Collider, and this is where Tim Berners-Lee invented the World Wide Web.

The first resistive touchscreen was developed by American inventor George Samuel Hurst in 1975, although the first practical version was not produced until 1982.

In 1982 theUniversity of Toronto’sInput Research Group developed the first multi-touch touchscreen, a screen that could interpret more than one touch at the same time.  The original device used a video camera behind a frosted piece of glass. Three years later the same group developed a multi-touch tablet that used a capacitive touchscreen instead.

The first commercial product to use a touchscreen was a point-of-sale terminal developed by Atari and displayed at the 1986 COMDEX expo in Las Vegas. The next year Casio launched theCasio PB-1000 pocket computerwith a touchscreen consisting of a simple 4×4 matrix.

LG created the world’s first capacitive touchscreen phone, theLG Pradaused a capacitive touchscreen and was released in early 2007. A few weeks later Apple released its first iPhone.

Most early touchscreen devices were resistive, as this technology is generally less expensive than capacitive screens. However, nowadays capacitive screens are more common, being used in the majority of smartphones and tablets.

Although they were invented after capacitive touchscreens, resistive touchscreens are probably the most common type used by hobbyists. The reason for that is the price and performance, resistive touchscreens are cheaper than capacitive ones and they are generally more accurate.

A resistive touchscreen consists of two thin layers of material, separated by a tiny gap.  Spacers are used to maintain the gap and keep the two sheets apart.

In operation, the resistance between the two sheets is measured at different points. Pressing down upon the tip sheet will change that resistance, and by comparing the measurement points it can be determined where the screen was pressed.  Essentially, it creates a pair of voltage dividers.

In a 4-Wire Analog touchscreen, there are two electrodes or “busbars” on each of the conductive layers.  On one layer these electrodes are mounted on the two X-axis sides, the other layer has them on the two y-axes.

This is the most inexpensive method of designing a resistive touchscreen. The touchscreen display that we will be working with today uses this arrangement.

In a 5-Wire Analog touchscreen, there are four wires, one connected to a circular electrode on each corner of the bottom layer. A fifth wire is connected to a “sensing wire”, which is embedded in the top layer.

Touching any point on the screen causes current to flow to each of the bottom electrodes, measuring all four electrode currents determines the position that the screen was touched.

This 8-Wire Analog touchscreen uses an arrangement of electrodes identical to the 4-Wire variety. The difference is that there are two wires connected to each electrode, one to each end.

Capacitive touchscreens are actually older technology than resistive displays.  They are commonly used in phones and tablets, so you’re probably familiar with them.

The capacitive touchscreen makes use of the conductivity of the human body. The touchscreen itself consists of a glass plate that has been treated with a conductive material.

The surface capacitive touchscreen is the most inexpensive design, so it is widely used. It consists of four electrodes placed at each corner of the touchscreen, which maintain a level voltage over the entire conductive layer.

When your finger comes in contact with any part of the screen, current flows between those electrodes and your finger. Sensors positioned under the screen sense the change in voltage and the location of that change.

This is a more advanced touchscreen technique. In a projected capacitive touchscreen transparent electrodes are placed along the protective glass coating and are arranged in a matrix.

One line of electrodes (vertical) maintain a constant level of current. Another line (horizontal) are triggered when your finger touches the screen and initiates current flow in that area of the screen.  The electrostatic field created where the two lines intersect determine where it was touched.

The module we will be experimenting with today is a very common Arduino Shield, which is rebranded by many manufacturers. You can easily find these on Amazon, eBay or at your local electronics shop.

You can also just use the shield as an LCD display and ignore the two other components, however, if you intend on doing that it would be cheaper just to buy an LCD display without any touchscreen features.

You do need to be looking directly at the display for best color accuracy, as most of these inexpensive LCD displays suffer from distortion and “parallax error” when viewed from the side. But as the most common application for a device like this is as a User Interface (UI) this shouldn’t be a problem.

This shield uses a 4-wire analog resistive touchscreen, as described earlier.  Two of the wires (one X and one Y) are connected to a couple of the analog inputs on the Arduino. The analog inputs are required as the voltage levels need to be measured to determine the position of the object touching the screen.

You should note that the microSD card uses the SPI interface and is wired