iic i2c twi serial 2004 20x4 lcd module shield free sample

This tutorial shows how to use the I2C LCD (Liquid Crystal Display) with the ESP32 using Arduino IDE. We’ll show you how to wire the display, install the library and try sample code to write text on the LCD: static text, and scroll long messages. You can also use this guide with the ESP8266.

Additionally, it comes with a built-in potentiometer you can use to adjust the contrast between the background and the characters on the LCD. On a “regular” LCD you need to add a potentiometer to the circuit to adjust the contrast.

Before displaying text on the LCD, you need to find the LCD I2C address. With the LCD properly wired to the ESP32, upload the following I2C Scanner sketch.

After uploading the code, open the Serial Monitor at a baud rate of 115200. Press the ESP32 EN button. The I2C address should be displayed in the Serial Monitor.

Displaying static text on the LCD is very simple. All you have to do is select where you want the characters to be displayed on the screen, and then send the message to the display.

In this simple sketch we show you the most useful and important functions from the LiquidCrystal_I2C library. So, let’s take a quick look at how the code works.

The next two lines set the number of columns and rows of your LCD display. If you’re using a display with another size, you should modify those variables.

Scrolling text on the LCD is specially useful when you want to display messages longer than 16 characters. The library comes with built-in functions that allows you to scroll text. However, many people experience problems with those functions because:

In a 16×2 LCD there are 32 blocks where you can display characters. Each block is made out of 5×8 tiny pixels. You can display custom characters by defining the state of each tiny pixel. For that, you can create a byte variable to hold  the state of each pixel.

In summary, in this tutorial we’ve shown you how to use an I2C LCD display with the ESP32/ESP8266 with Arduino IDE: how to display static text, scrolling text and custom characters. This tutorial also works with the Arduino board, you just need to change the pin assignment to use the Arduino I2C pins.

LCD2004-character LCD display module is a new high-quality 4 line 20 character LCD module not only set the contrast control knob selector switch also has a backlight and IIC communication interface. For Arduino beginners, not for the cumbersome and complex LCD driver circuit connection and a headache, the real significance of this LCD module will simplify the circuit, this module directly into the Arduino Sensor Shield V5.0 sensor expansion board IIC device interface can, GM 4P sensor connection cable, programmed through the Arduino controller, you can easily identify the slogan, sensor data records

With IIC/I2C interface, it only takes two I/O port thus saving more for other usages. You can adjust the contrast by the potentiometer at its back. If you dont want the backlight, you can also unplug the jumper cap at the LCD back.

Easy to set up, and works with the standard "LiquidCrystal_I2C" library.Contrast adjustable as described.2 cons:1) Red glow always from the top right and bottom left corners. Not bright, but there.2) A long message line continues from line 0 to line 2, ie. it skips a line, then goes back to line 1, and then to line 3. Not sure if this is fault of the hardware, or the library driver.To note - if I place the cursor on a specific line, it prints the specified message there OK.See code below and video.#include #include // initialize the library with the numbers of the interface pinsLiquidCrystal_I2C lcd(0x27,20,4); // set the LCD address to 0x27 for a 20 chars and 4 line displaychar message[] = "This is some long message that will end up scrolling on Line0 only";int previous = 0;int pos = 0;void setup(){ lcd.init(); //initialize the lcd lcd.backlight(); //open the backlight // Print a message to the LCD. lcd.print(message); delay(5000); lcd.clear();}void printLine(int refreshSeconds){ //Check if the current second since restart is a mod of refresh seconds, //if it is then update the display , it must also not equal the previously //stored value to prevent duplicate refreshes if((millis()/500) % refreshSeconds == 0 && previous != (millis()/500)) { previous = (millis()/500);//Store the current time we entered for comparison on the next cycle lcd.setCursor(0, 0);//Set our draw position , set second param to 0 to use the top line char lcdTop[20];//Create a char array to store the text for the line int copySize = 20; // What is the size of our screen , this could probably be moved outside the loop but its more dynamic like this if(strlen(message) < 20) { //if the message is bigger than the current buffer use its length instead; copySize = strlen(message); } //Store the current position temporarily and invert its sign if its negative since we are going in reverse int tempPos = pos; if(tempPos < 0) { tempPos = -(tempPos); } //Build the lcd text by copying the required text out of our template message variable memcpy(&lcdTop[0],&message[tempPos],copySize); lcd.print(lcdTop);//Print it from position 0 //Increase the current position and check if the position + 20 (screen size) would be larger than the message length , if it is go in reverse by inverting the sign. pos += 1; if(pos +20 >= strlen(message)) { pos = -(pos); } }}void loop(){ printLine(1); // Original program line lcd.setCursor(0,1); lcd.print("This is Line1 msg"); delay(250); lcd.setCursor(0,2); lcd.print("This is Line2 msg"); delay(250); lcd.setCursor(0,3); lcd.print("This is Line3 msg"); delay(250); lcd.clear(); }

The Arduino family of devices is features rich and offers many capabilities. The ability to interface to external devices readily is very enticing, although the Arduino has a limited number of input/output options. Adding an external display would typically require several of the limited I/O pins. Using an I2C interface, only two connections for an LCD character display are possible with stunning professional results. We offer both a 4 x 20 LCD.

The character LCD is ideal for displaying text and numbers and special characters. LCDs incorporate a small add-on circuit (backpack) mounted on the back of the LCD module. The module features a controller chip handling I2C communications and an adjustable potentiometer for changing the intensity of the LED backlight. An I2C LCD advantage is that wiring is straightforward, requiring only two data pins to control the LCD.

A standard LCD requires over ten connections, which can be a problem if your Arduino does not have many GPIO pins available. If you happen to have an LCD without an I2C interface incorporated into the design, these can be easily

The LCD displays each character through a matrix grid of 5×8 pixels. These pixels can display standard text, numbers, or special characters and can also be programmed to display custom characters easily.

Connecting the Arduino UNO to the I2C interface of the LCD requires only four connections. The connections include two for power and two for data. The chart below shows the connections needed.

The I2C LCD interface is compatible across much of the Arduino family. The pin functions remain the same, but the labeling of those pins might be different.

Located on the back of the LCD screen is the I2C interface board, and on the interface is an adjustable potentiometer. This adjustment is made with a small screwdriver. You will adjust the potentiometer until a series of rectangles appear – this will allow you to see your programming results.

The Arduino module and editor do not know how to communicate with the I2C interface on the LCD. The parameter to enable the Arduino to send commands to the LCD are in separately downloaded LiquidCrystal_I2C library.

The LiquidCrystal_I2C is available from GitHub. When visiting the GitHub page, select the Code button and from the drop-down menu, choose Download ZIP option to save the file to a convenient location on your workstation.

Before installing LiquidCrystal_I2C, remove any other libraries that may reside in the Arduino IDE with the same LiquidCrystal_I2C name. Doing this will ensure that only the known good library is in use. LiquidCrystal_I2C works in combination with the preinstalled Wire.h library in the Arduino editor.

To install the LiquidCrystal_I2C library, use the SketchSketch > Include Library > Add .ZIP Library…from the Arduino IDE (see example). Point to the LiquidCrystal_I2C-master.zip which you previously downloaded and the Library will be installed and set up for use.

Several examples and code are included in the Library installation, which can provide some reference and programming examples. You can use these example sketches as a basis for developing your own code for the LCD display module.

The I2c address can be changed by shorting the address solder pads on the I2C module. You will need to know the actual address of the LCD before you can start using it.

Once you have the LCD connected and have determined the I2C address, you can proceed to write code to display on the screen. The code segment below is a complete sketch ready for downloading to your Arduino.

The code assumes the I2C address of the LCD screen is at 0x27 and can be adjusted on the LiquidCrystal_I2C lcd = LiquidCrystal_I2C(0x27,16,2); as required.

This function turns off any characters displayed to the LCD. The text will not be cleared from the LCD memory; rather, it is turned off. The LCD will show the screen again when display() is executed.

Scrolling text if you want to print more than 16 or 20 characters in one line then the scrolling text function is convenient. First, the substring with the maximum of characters per line is printed, moving the start column from right to left on the LCD screen. Then the first character is dropped, and the next character is displayed to the substring. This process repeats until the full string has been displayed on the screen.

The LCD driver backpack has an exciting additional feature allowing you to create custom characters (glyph) for use on the screen. Your custom characters work with both the 16×2 and 20×4 LCD units.

To aid in creating your custom characters, there are a number of useful tools available on Internet. Here is a LCD Custom Character Generator which we have used.