arduino lcd touch screen code 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.

As the code is a bit longer and for better understanding I will post the source code of the program in sections with description for each section. And at the end of this article I will post the complete source 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.

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:

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.

We need three libraries for this program to work; all these three libraries were given in the ZIP file you downloaded from the above provided link. I have simply included them in the code as shown below.

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.

Now, you can enter any number and perform your calculations. It is limited to only two operand and only operator for now. But, you can tweak the code to make it have lots of option.

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 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.

Spice up your Arduino project with a beautiful large touchscreen display shield with built in microSD card connection. This TFT display is big 4"(3.97" diagonal) bright (6 white-LED backlight) and colorful (18-bit 262,000 different shades)! 480x800 pixels with individual pixel control. As a bonus, this display has a optional resistive touch panel with controller XPT2046 and capacitive touch panel with FT6336.

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 (Due/Mega 2560).

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.

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.

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 for the Arduino Uno. While the rest of the shield will function with an Arduino Mega 2560, the SPI connections on the Mega are different, so the microSD card will not work.

The last paragraph regarding the microSD card may make you think that an Arduino Uno is the best choice for the Touchscreen Display Shield.  And it you require the microSD card then it probably is a good choice.

But using an Arduino Uno with this shield does have one big disadvantage – a limited number of free I/O pins.  In fact there are only three pins left over once the card has been plugged in:

If your product is self-contained and doesn’t need many (or any) I/O pins then you’ll be fine. But if you need more pins to interface with then an Arduino Mega 2560 is a much better choice. It has a lot of additional analog and digital pins.

So if you don’t require the microSD card, or are willing to hook up a separate microSD card, then the Arduino Mega 2560 is a better choice for most applications.

As there are three devices on the shield you will need libraries for each of the ones you want to use.  TheSD Libraryis already installed in your Arduino IDE, so you will just need libraries for the display and touchscreen.

For the LCD you will have a lot of choices in libraries. Most of these shields come with a CD ROM with some sketches and libraries, so you can use the LCD libraries there. Bear in mind however that code on these CD ROMs tends to be a little dated, you may have better lick on the vendors website.

This useful resource contains code, libraries and datasheets for a wealth of LCD displays, both touchscreen and non-touchscreen. You’ll also find code for some common OLED displays as well.

I ran my touchscreen through all of the code samples I obtained from the LCD Wiki. It’s an interesting exercise, and by examining the sketch for each demo you can learn a lot about programming the display.

The first example is a very simple color “sweep” test. Navigate to theExample_01_Simple_testfolder and open the folder for your Arduino controller.  Navigate down until you find the “ino” file and load it.

This test does not make use of any of the extra libraries, it drives the LCD directly. It is only a test of the LCD display, it does not make use of the touchscreen membrane.

You’ll find this example in theExample_02_clear_screenfolder, the sameclear_Screen.inoexample is used for both the Uno and Mega so there are no separate folders.

This example does use the custom libraries, and is a very good way to learn how to use them.  You’ll note that theLCDWIKI_GUI.hlibrary is loaded, which is the graphics library for the LCD display.

Another library, LCDWIKI_KBV.h, is loaded as well. This is a hardware-specific “helper” library that provides an interface to the actual hardware for the other libraries.

When you run this example the results will be similar to the first one, a series of colors will sweep across the screen. In this case the colors are different, and they vary in speed.

A look at the loop will show how this is done. TheLCDWIKI_GUI.hlibrary has a “Fill_Screen” method that fills the screen with an RGB color. You can specify the color in both hexadecimal or decimal format, the example illustrates both ways.

The example itself is in a folder labeled “Example_03_colligate_test” and the code itself is in the colligate_test.ino file. I suspect a translation error resulted in the name!

This sketch uses a number of functions from theLCDWIKI_GUI.hlibrary, along with some custom functions to draw geometric shapes. It then displays a cycle of graphs, shapes, and patterns on the LCD display.

The result of running the sketch is the display screen fills with rows of hexadecimal values while the background alternates between blue and black and the orientation (or “aspect”) changes.  If you stand back to see the “big picture” you’ll note that the color values form “number patterns”.

In addition to the graphics and “helper” libraries that have been used in the previous examples this sketch also uses theTouchScreenlibrary to read screen interaction.  This was one of the libraries included in the original ZIP file.

Note that this demo will only work on the Arduino Uno, as the microSD card uses the SPI bus and is wired to the Arduino Uno SPI port. The Arduino Mega 2560 board uses different pins for SPI.

The image needs to be in bitmap format as this format defines several bytes for each individual pixel in the image. There are four 320×480 sample images included in the code sample, you can also use your own if you (a) keep them the same size and (b) give them the same names.

Another thing you will notice is the speed at which the images draw, which is not particularly impressive. The clock speed of the Arduino has a lot to do with this, as does the method used to extract each individual pixel from the image.

This example draws some small “switches” on the display. The switches are active and respond to touch.  There are slide switches, a push button, some radio buttons and some text-based expandable menus to test with.

The Touch Pen example is actually a pretty decent little drawing application. You can draw whatever you want on the main screen area. A set of buttons allow you to set the stylus color and pen width.

While the sample code is a bit difficult to follow it’s worth the effort, as it shows you how to create a dynamic menu system. Touching the stylus color button, for example, will open a new menu to select colors.  This is a handy technique that you’ll need to know when developing your own user interfaces.

The Calibration utility lets you calibrate the resistive touchscreen.  It achieves this by placing a number of crosses on the screen. You can calibrate the screen by using the stylus to touch the center of one of the crosses as accurately as you can.

After you touch one of the cross points the sketch runs through a calibration sequence, during which time you need to continue to touch the cross point. You’ll be informed when it is finished.

After calibration, the sketch will display a number of calibration values for the resistive touchscreen. These values can be used in your future sketches to make the touchscreen more accurate.

The examples are a great way to demonstrate the capabilities of your touchscreen. But to really put your interface to work you’ll need to write your own interface code.

Writing a touchscreen interface can be challenging. I would suggest that you start by modifying one of the example codes, one that is closest to your desired interface.

For my experiment, I will be using an Arduino Mega 2560 to drive three LEDs. I used a Red, Green and Blue LED but really any colors will work – I just wanted my LED colors to match my button colors.

The digital I/O connector at the back of the Mega is still accessible even when the touchscreen display shield is installed, so I used three of those connections for the LEDs. I hooked up each LED anode through a 220-ohm dropping resistor and connected them as follows:

The sketch is based upon the telephone keypad sketch. I modified it to eliminate the other functions and just display three buttons.  Then I added code to toggle the LEDs.

TheAdafruit TFTLCD Libraryis used. It uses the previous library to provide an easy method of drawing on the LCD display.  It works with LCD displays that use driver chips like the ILI9325 and ILI9328.

TheTouchScreenlibrary comes in the code that you downloaded from the LCD Wiki or from the CD ROM included with your touchscreen shield.  As its name implies it is used to interface with the touchscreen.

We also define some “human-readable” colors to use within our code, it’s a lot simpler and more intuitive than providing RGB values.  I’ve includes all of the colors from the phone sketch I used as the basis for this code, so if you want to change button or background color you can easily do it.

Next, we define some touchscreen parameters. You can ‘fine-tune” your code here by using parameters from your own display, which you can obtain from the Calibration Sketch we ran from the sample code.  Otherwise, just use the values here and you should be fine.

Now, still in the Setup, we set up the LCD display rotation and fill the background in black. Next step is to draw our buttons. Once we are done that the Setup is finished, and our screen should be displaying the three buttons on a black background.

The loop is where we will be monitoring the screen for keypresses. If we get one, and if its position corresponds to a button location, then we need to toggle the correct LED.

We start by triggering the touchscreen, which is done by toggling pin 13 on the Arduino high. If something is touching the screen we read it and assign it to a TSPoint object named “p”.

We then need to reset the pin modes for two of the touchscreen pins back to outputs. This is done as these pins get shared with other LCD display functions and get set as inputs temporarily.

Now we check to see if the pressure on the screen was within the minimum and maximum pressure thresholds we defined earlier.  If it makes the grade then we determine where exactly the screen was pressed.

Now that we know where the screen was pressed we need to see if the pressure point corresponds to one of our buttons.  So we cycle through the button array and check to see if the pressure point was within 10 pixels of our button location.

Load the code into your Arduino IDE and upload it to your Arduino Mega 2560. Make sure you have the correct processor-type set in your Arduino IDE, especially if you are used to working with the Uno!

This is a pretty simple demo but it does illustrate how to create a simple IDE. You can expand upon it to add more buttons, or to change the button colors or shapes. And, of course, you don’t have to light LEDs with your buttons, they can control anything that you can connect to your Arduino.

Touchscreen interfaces are used in a number of products, and now you can design your own devices using them. They can really make for an intuitive and advanced display and will give your project a very professional “look and feel” if done correctly.

This is not the only time we will look at touchscreen displays. Next time we’ll examine a capacitive touchscreen and we’ll explore the Adafruit Graphics libraries further to create some very fancy displays with controls and indicators.

Let"s learn how to use a touchscreen with the Arduino. We will examine the different types of touchscreens and will then create a simple interface using an inexpensive Arduino touchscreen shield.

For more information on how to use the Simulink Support Package for Arduino Hardware to run a Simulink model on an Arduino board, see Getting Started with Arduino Hardware.

4. Select Enable code generation for Dashboard blocks and click Launch Display Configuration Setup to launch the wizard to configure the dashboard properties.

Due to memory constraints, the appplication dashboard may not deploy on an Arduino board with less memory than the Arduino Mega 2560 board, such as an Arduino Uno or Arduino Leonardo. To ensure successful deployment of the application dashboard on your Arduino board, consider deploying a dashboard that consists of only a few dashboard elements. For example, you can remove the Display dashboard block to reduce the memory size of the application dashboard.

Arduino Due board does not support the touch screen capability of the Adafruit ILI 9341 Touch TFT display. To try this example on the Arduino Due board, use one of these solutions:

2. Use a custom display that the Arduino Due board supports. Note that you must configure this display in the Display properties section of the Configuration Parameters dialog box.

Implement the dashboard on a custom graphical display. Make sure to appropriately configure the Dashboard properties in the Configuration Parameters dialog box. Use the datasheet for the display to ensure you make the correct connections with your Arduino board.

Implement the dashboard panel on the LCD display of your choice for the Arduino Based Smart Watering of Plants example. Use the Display and Push Button blocks to implement the dashboard.

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.

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.

This post is an introduction to the Nextion display with the Arduino. We’re going to show you how to configure the display for the first time, download the needed resources, and how to integrate it with the Arduino UNO board. We’ll also make a simple graphical user interface to control the Arduino pins.

Nextion is a Human Machine Interface (HMI) solution. Nextion displays are resistive touchscreens that makes it easy to build a Graphical User Interface (GUI). It is a great solution to monitor and control processes, being mainly applied to IoT applications.

Connecting the Nextion display to the Arduino is very straightforward. You just need to make four connections: GND, RX, TX, and +5V. These pins are labeled at the back of your display, as shown in the figure below.

You can power up the Nextion display directly from the Arduino 5V pin, but it is not recommended. Working with insufficient power supply may damage the display. So, you should use an external power source. You should use a 5V/1A power adaptor with a micro USB cable. Along with your Nextion display, you’ll also receive a USB to 2 pin connector, useful to connect the power adaptor to the display.

The best way to get familiar with a new software and a new device is to make a project example. Here we’re going to create a user interface in the Nextion display to control the Arduino pins, and display data.

The user interface has two pages: one controls two LEDs connected to the Arduino pins, and the other shows data gathered from the DHT11 temperature and humidity sensor;

All components have an attribute called objname. This is the name of the component. Give good names to your components because you’ll need them later for the Arduino code. Also note that each component has one id number that is unique to that component in that page. The figure below shows the objname and id for the slider.

You should trigger an event for the touchable components (the buttons and the slider) so that the Arduino knows that a component was touched. You can trigger events when you press or when you release a component.

To do that, select one of the buttons, and in the event window, select the Touch Release Event tab, and put a tick on the Send Component ID option. Repeat this process for the other button, and the slider.

Notice that we have labels to hold the units like “ºC”, “ºF” and “%”, and empty labels that will be filled with the readings when we have our Arduino code running.

Once the GUI is ready, you need to write the Arduino code so that the Nextion can interact with the Arduino and vice-versa. Writing code to interact with the Nextion display is not straightforward for beginners, but it also isn’t as complicated as it may seem.

A good way to learn how to write code for the Arduino to interact with the Nextion display is to go to the examples folder in the Nextion library folder and explore. You should be able to copy and paste code to make the Arduino do what you want.

The first thing you should do is to take note of your components in the GUI that will interact with the Arduino and take note of their ID, names and page. Here’s a table of all the components the code will interact to (your components may have a different ID depending on the order you’ve added them to the GUI).

In this post we’ve introduced you to the Nextion display. We’ve also created a simple application user interface in the Nextion display to control the Arduino pins. The application built is just an example for you to understand how to interface different components with the Arduino – we hope you’ve found the instructions as well as the example provided useful.

An excellent new compatible library is available which can render TrueType fonts on a TFT screen (or into a sprite). This has been developed by takkaO and is available here. I have been reluctant to support yet another font format but this is an amazing library which is very easy to use. It provides access to compact font files, with fully scaleable anti-aliased glyphs. Left, middle and right justified text can also be printed to the screen. I have added TFT_eSPI specific examples to the OpenFontRender library and tested on RP2040 and ESP32 processors, however the ESP8266 does not have sufficient RAM. Here is a demo screen where a single 12kbyte font file binary was used to render fully anti-aliased glyphs of gradually increasing size on a 320x480 TFT screen:

For ESP32 ONLY, the TFT configuration (user setup) can now be included inside an Arduino IDE sketch providing the instructions in the example Generic->Sketch_with_tft_setup are followed. See ReadMe tab in that sketch for the instructions. If the setup is not in the sketch then the library settings will be used. This means that "per project" configurations are possible without modifying the library setup files. Please note that ALL the other examples in the library will use the library settings unless they are adapted and the "tft_setup.h" header file included. Note: there are issues with this approach, #2007 proposes an alternative method.

Support has been added in v2.4.70 for the RP2040 with 16 bit parallel displays. This has been tested and the screen update performance is very good (4ms to clear 320 x 480 screen with HC8357C). The use of the RP2040 PIO makes it easy to change the write cycle timing for different displays. DMA with 16 bit transfers is also supported.

Users of PowerPoint experienced with running macros may be interested in the pptm sketch generator here, this converts graphics and tables drawn in PowerPoint slides into an Arduino sketch that renders the graphics on a 480x320 TFT. This is based on VB macros created by Kris Kasprzak here.

The RP2040 8 bit parallel interface uses the PIO. The PIO now manages the "setWindow" and "block fill" actions, releasing the processor for other tasks when areas of the screen are being filled with a colour. The PIO can optionally be used for SPI interface displays if #define RP2040_PIO_SPI is put in the setup file. Touch screens and pixel read operations are not supported when the PIO interface is used.

The library now supports the Raspberry Pi Pico with both the official Arduino board package and the one provided by Earle Philhower. The setup file "Setup60_RP2040_ILI9341.h" has been used for tests with an ILI9341 display. At the moment only SPI interface displays have been tested. SPI port 0 is the default but SPI port 1 can be specifed in the setup file if those SPI pins are used.

An Arduino IDE compatible graphics and fonts library for 32 bit processors. The library is targeted at 32 bit processors, it has been performance optimised for STM32, ESP8266 and ESP32 types. The library can be loaded using the Arduino IDE"s Library Manager. Direct Memory Access (DMA) can be used with the ESP32, RP2040 and STM32 processors with SPI interface displays to improve rendering performance. DMA with a parallel interface is only supported with the RP2040.

For other processors the generic only SPI interface displays are supported and slower non-optimised standard Arduino SPI functions are used by the library.

The library supports some TFT displays designed for the Raspberry Pi (RPi) that are based on a ILI9486 or ST7796 driver chip with a 480 x 320 pixel screen. The ILI9486 RPi display must be of the Waveshare design and use a 16 bit serial interface based on the 74HC04, 74HC4040 and 2 x 74HC4094 logic chips. Note that due to design variations between these displays not all RPi displays will work with this library, so purchasing a RPi display of these types solely for use with this library is not recommended.

Some displays permit the internal TFT screen RAM to be read, a few of the examples use this feature. The TFT_Screen_Capture example allows full screens to be captured and sent to a PC, this is handy to create program documentation.

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