### Project 11 LCD

**1. Description**

Arduino I2C 1602 LCD is a commonly-used auxiliary device for MCU development board to connect with external sensors and modules. It features a 16-bit wide character, 2-line LCD screen and adjustable brightness. This programable module is convenient for data editing, display and management . Besides, it can display not only characters and figures but sensors value, like temperature, humidity or pressure value. 

As a result of its usability, the display is wildly applied in many fields, including smart home products, industrial monitoring systems, robot control systems and automotive electronics systems.

**2.  Working Principle**

![](./media/A44.png)

It is the same as IIC communication principle. Underlying functions have been packaged in libraries so that you can recall them directly. If you are interested in these, you may have a further look of underlying driving principles. 

**3. Wiring Diagram**

![](./media/A45.png)

**4.Test Code**

```
/*
  keyestudio ESP32 Inventor Learning Kit 
  Project 11 LCD
  http://www.keyestudio.com
*/
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2); // set the LCD address to 0x27 for a 16 chars and 2 line display

void setup()
{
    lcd.init(); // initialize the lcd
    // Print a message to the LCD.
    lcd.backlight();		//Turn on the LCD backlight 
    lcd.setCursor(2,0);		//Set the display position 
    lcd.print("Hello,world!");		//LCD displays "Hello, world!"
    lcd.setCursor(2,1);	
    lcd.print("keyestudio!");		//LCD displays "keyestudio!"
}

void loop()
{
}
```

**5. Test Result**

After connecting the wiring and uploading code, turn on the LCD,  "Hello, world!" and "keyestudio!" will be displayed on the LCD. 

![](./media/A46.png)

If the characters are unclear, please fix the backlight potentiometer by the small slotted screwdriver(Please use appropriate force to adjust. Connect an external power supply if necessary.

![](./media/A47.png)

![](./media/A48.png)