arduino uno 2.4 tft lcd display shield touch panel ili9341 free sample

ILI9341 is integrated inside the display. It drives the display and has nothing to do with touchscreen (Although the shield connects some pins of ILI9341 together with pins of the touchscreen).

ILI9341 interpretes input byte as command (if RS=0) or as data/parameter (RS=1). You have first to send a command to ILI and then write or read data/parameters. CS pin has to be LOW during the communication, WR rising from LOW to HIGH tells to ILI to read byte on data pins. To read a byte from ILI after sending a read command (e.g. 09h - Read Display Status) set RD from HIGH to LOW, so ILI9341 outputs data until RD returns HIGH.

To draw a rectangle (or just one pixel) on the screen you have to tell to ILI the area (start_column, end_column, start_row, end_row, commands 0x2Ah and 0x2Bh) you want to draw. Then command 0x2Ch. Then send in sequence for every single pixel in the area a value of the color to display. The color has 2 byte format.

The touch screen is attached on the surface of the display. It connects through 4 wires, which share arduino pins 8, 9, A2, A3 with ILI. So you can"t write to LCD display and read the touch screen in the same time.

Touch-screen devices using resistive technology, a two-dimensional membrane potentiometer provides x and y coordinates. The top layer is thin glass spaced close to a neighboring inner layer. The underside of the top layer has a transparent conductive coating; the surface of the layer beneath it has a transparent resistive coating. A finger or stylus deforms the glass to contact the underlying layer. Edges of the resistive layer have conductive contacts. Locating the contact point is done by applying a voltage to opposite edges, leaving the other two edges temporarily unconnected. The voltage of the top layer provides one coordinate. Disconnecting those two edges, and applying voltage to the other two, formerly unconnected, provides the other coordinate. Alternating rapidly between pairs of edges provides frequent position updates. An analog-to digital converter provides output data.

First we need to detect if there is a touch. So we connect both wires of one layer/membrane, e.g. X to ground (LOW from ardiuno pins set as output) and one wire from layer Y to pull-up resistor (setting corresponding arduino pin as INPUT_PULLUP). Reading the second wire of Y layer we get HIGH if there is no touch (because of pull-up) and LOW if there is a touch (because of contact with grounded X layer).

Then we need to read a position of a touch. So we set one of the X wires to HIGH (which one depends on on which side of touch screen we want to read min/max value; see variant A/B in the code) and we read analog value on Y. The value should be in the range 0-1023, but touchscreen I tested returns 110-910 (So it need to be calibrated - run ILI9341_7.ino). Then we apply LOW-HIGH on Y layer and read analog value on X.

Touchscreen I tested sometimes wrongly detects a touch, outside of the touched point. To prevent this I added some delays and the X and Y analog value is read repeatedly and touch is approved only if values do not differ (a lot).

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.

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Spice up your Arduino project with a beautiful touchscreen display shield with built in microSD card connection. This TFT display is 2.4" diagonal and colorful (18-bit 262,000 different shades)! 240x320 pixels with individual pixel control. As a bonus, this display has a optional capacitive touch panel and resistive touch panel with controller XPT2046 attached 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 (UNO/Due/Mega 2560).

This display shield has a controller built into it with RAM buffering, so that almost no work is done by the microcontroller. You can connect more sensors, buttons and LEDs.

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 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.

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:

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.

An obvious use for the SD reader is to log readings from sensors and display the results on the TFT display. Unfortunately,  the shield covers and uses most of the pins. The solution is to connect just the SD reader and power pins with jump leads which leaves plenty of pins to collect data from sensors.

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.

The second sketch reads the data we have saved in the datalog6.txt file. It splits each line/record into the 3 strings and then converts one to an Integer and the another to Floating Point. Just to prove that they are now stored as numbers it multiplies them together and displays the result.

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.

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.

The SD card reader is a bonus, and could always be used, via jump wires, to record values from sensors on the other pins. These values could then be displayed graphically on the display with a different sketch.

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.