ESP32 Tutorial 11/55 - Using LCD1602 LCD2004 with ESP32 -SunFounder's ESP32 IoT Learning kit

This lesson is part of: ESP32 Arduino Course based on SunFounder's ESP32 IoT Learning kit (55 Tutorials/Videos)

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ESP32 Tutorial 11/55 - Using LCD1602 LCD2004 with ESP32 -SunFounder's ESP32 IoT Learning kit

In this tutorial, we will explore how to use the LCD1602 and LCD2004 with the ESP32 microcontroller. These LCD screens allow us to display text and other information effectively, enhancing our projects with visual feedback. We will also cover how to adjust the contrast to ensure readability.

The ESP32, part of the SunFounder ESP32 IoT Learning kit, has built-in Wi-Fi and Bluetooth capabilities, making it a powerful tool for various IoT applications. By connecting the LCD to the ESP32, we can easily display messages or data outputs from our code, making our projects more interactive and user-friendly (in video at 00:30).

Hardware Explained

The main components we will use include the ESP32 microcontroller and the LCD1602 or LCD2004 display module. The ESP32 will serve as the brain of our project, processing inputs and controlling outputs, including the LCD display.

The LCD module communicates via I2C, which simplifies wiring by using only two data pins (SDA and SCL) for communication, along with power and ground connections. This setup significantly reduces the complexity of connecting multiple pins, allowing for a cleaner and more manageable circuit.

Datasheet Details

Manufacturer	SunFounder
Part number	LCD1602
Logic/IO voltage	5 V
Supply voltage	5 V
Display size	16 x 2 characters
Backlight	Yes
Interface	I2C
Dimensions	80 x 36 mm
Notes / variants	Commonly used with I2C address 0x27

SunFounder-ESP32-Lesson-11-LCD1602.mp4_snapshot_20.23.926

Ensure proper voltage supply (5 V) to prevent damage.
Use short wires to minimize interference on I2C lines.
Adjust the potentiometer for optimal contrast visibility.
Check I2C address if the display does not initialize (common addresses: 0x27, 0x3F).
Clear the display before updating messages to avoid overlap.

Wiring Instructions

To wire the LCD1602 to the ESP32, first connect the ground pin of the LCD to the ground pin on the ESP32. Then, connect the VCC pin of the LCD to the 5V output of the ESP32. For the I2C communication, connect the SDA pin of the LCD to pin 21 on the ESP32, and connect the SCL pin of the LCD to pin 22 on the ESP32. Make sure the connections are secure to avoid any communication issues.

It is important to note that while the ESP32 operates at 3.3V logic levels, the LCD1602 requires 5V for proper operation. Therefore, ensure that you are using the correct voltage supply to avoid damaging the LCD. If you are using a different LCD size, adjust the wiring accordingly based on the I2C address and specifications.

Code Examples & Walkthrough

In the code, we begin by including the necessary libraries for I2C communication and the LCD. We create an instance of the LCD using the I2C address 0x27 and specify that it has 16 columns and 2 rows.

#include  
#include 

LiquidCrystal_I2C lcd(0x27,16,2);  // set the LCD address to 0x27 for a 16 chars and 2 line display

This setup allows us to control the LCD easily. In the setup() function, we initialize the LCD and turn on the backlight, followed by printing a welcome message.

void setup()
{
  lcd.init(); // initialize the lcd 
  lcd.backlight(); // Turns on the LCD backlight.
  lcd.print("Hello, world!");   // Print a message to the LCD.
  delay(3000);
}

In the loop() function, we continuously update the display by clearing it, setting the cursor position, and printing the current count value. This demonstrates how the LCD can dynamically show changing information.

void loop()
{
  lcd.clear(); 
  lcd.setCursor(0, 0); // Sets the cursor position to the first row and first column (0, 0).
  lcd.print("COUNT: ");
  lcd.print(count); // Prints the current value of the count variable.
  delay(1000);
  count++; // Increments the counter by 1. 
}

The full code will load below the article, where you can see the complete implementation and any additional functionalities added for your project.

Demonstration / What to Expect

Once everything is connected and the code is uploaded, the LCD should display "Hello, world!" for 3 seconds before starting a counter that increments every second. You can adjust the contrast using the potentiometer to ensure that the text is easily readable (in video at 08:45).

If you encounter any issues, check the wiring connections and ensure the correct I2C address is being used. A common mistake is not matching the LCD's I2C address with what is set in the code, which can prevent the display from functioning properly.