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Lesson 01: Button Module

In this lesson, you will learn how a button interacts with an LED using ESP32 Development Board. We’ll see how pressing the button lights up the LED and releasing it turns off the LED. This project is ideal for beginners as it provides a practical understanding of input and output operations on the ESP32 platform.

Required Components

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name	ITEMS IN THIS KIT	LINK
Universal Maker Sensor Kit	94	Universal Maker Sensor Kit

You can also buy them separately from the links below.

Component Introduction	Purchase Link
ESP32 & Development Board (ESP32 Board)	BUY
Button Module	-
Breadboard	BUY

Wiring

Code

Code Analysis

Initialization of Pins

The pins for the button and LED are defined and initialized. The buttonPin is set as an input to read the button’s state, and ledPin is set as an output to control the LED.

const int buttonPin = 26;  // Pin number for the button
const int ledPin = 25;     // Pin number for the LED
int buttonState = 0;  // Variable to hold the current state of the button

Setup Function

This function runs once and sets up the pin modes. pinMode(buttonPin, INPUT) configures the button pin as an input. pinMode(ledPin, OUTPUT) sets the LED pin as an output.
```
void setup() {
  pinMode(buttonPin, INPUT);  // Initialize buttonPin as an input pin
  pinMode(ledPin, OUTPUT);    // Initialize ledPin as an output pin
}
```
Main Loop Function

This is the core of the program where the button state is continuously read and the LED state is controlled. digitalRead(buttonPin) reads the button’s state. If the button is pressed (state is LOW), the LED is turned on by digitalWrite(ledPin, HIGH). If not pressed, the LED is turned off (digitalWrite(ledPin, LOW)).

The button module used in this project has an internal pull-up resistor (see its schematic diagram), causing the button to be at a low level when pressed and remain at a high level when released.
```
void loop() {
  // Read the current state of the button
  buttonState = digitalRead(buttonPin);

  // Check if the button is pressed (LOW)
  if (buttonState == LOW) {
    digitalWrite(ledPin, HIGH);  // Turn the LED on
  } else {
    digitalWrite(ledPin, LOW);  // Turn the LED off
  }
}
```