How to Handle Digital Inputs and Outputs with the ESP32 in Arduino IDE

 In this tutorial, we’ll cover how to handle digital inputs and outputs with the ESP32 using the Arduino IDE. Specifically, we’ll show you how to read the state of a pushbutton and use that to control an LED. This is a fundamental skill when working with embedded systems and forms the foundation for more complex IoT projects.

Before diving into this tutorial, we recommend reviewing the basics of the ESP32 LED blink tutorial if you haven't already.

Components Needed

To build this simple project, you'll need the following components:

• ESP32 Board
• 5mm LED
• 330 Ohm Resistor
• Pushbutton
• 10k Ohm Resistor (for pull-down)
• Breadboard
• Jumper Wires

Circuit Assembly

Follow these steps to set up your circuit:

1. Connect the LED:

• Attach the anode (long leg) of the LED to GPIO 16 of the ESP32.
• Connect the cathode (short leg) of the LED to one end of the 330 Ohm resistor.
• Connect the other end of the 330 Ohm resistor to the ground (GND) pin on the ESP32.

2. Connect the Pushbutton:

• One leg of the pushbutton goes to GPIO 4 on the ESP32.
• The opposite leg of the pushbutton connects to a 10k Ohm pull-down resistor that is connected to ground (GND).
• The same leg of the pushbutton that connects to the resistor also connects to the 3.3V power rail.

Schematic Diagram

Here’s the circuit diagram that illustrates how to wire the components together:

[Insert ESP32 push button and LED circuit diagram]

ESP32 Program Code

Once your circuit is assembled, you can upload the following code to your ESP32 using the Arduino IDE:

 
 // Set pin numbers
const int buttonPin = 4; // Pin number for the pushbutton
const int ledPin = 16;   // Pin number for the LED

// Variable for storing the pushbutton state
int buttonState = 0;

void setup() {
  Serial.begin(115200);  // Initialize serial communication
  pinMode(buttonPin, INPUT);   // Set pushbutton pin as input
  pinMode(ledPin, OUTPUT);     // Set LED pin as output
}

void loop() {
  // Read the state of the pushbutton
  buttonState = digitalRead(buttonPin);
  Serial.println(buttonState);

  // Check if the pushbutton is pressed
  // If pressed, the buttonState will be HIGH
  if (buttonState == HIGH) {
    // Turn LED off
    digitalWrite(ledPin, LOW);
  } else {
    // Turn LED on
    digitalWrite(ledPin, HIGH);
  }
}

Testing Your Project

After uploading the code, you can test your circuit:

• When the pushbutton is pressed, the LED should turn off.
• When the pushbutton is released, the LED should turn on.

If you're experiencing any issues with uploading code to the ESP32, check out our guide on solving common ESP32 errors in the Arduino IDE here.

Summary

In this tutorial, you learned how to handle digital inputs and outputs with the ESP32 using the Arduino IDE. Specifically, we demonstrated how to read the state of a pushbutton and control an LED based on that input. This foundational knowledge can be applied to more advanced projects such as building IoT devices, automation systems, and more.

For more detailed guides, tutorials, and project ideas, check out our other useful resources:

• LED Blink Tutorial with Arduino Nano: LED Blink Arduino Nano Tutorial
• ESP32 PWM with Example for Dimming LED: ESP32 PWM Dimming LED Tutorial
• How to Detect Sound Levels with Arduino: Arduino Sound Level Detection

By following these tutorials, you can expand your knowledge of ESP32 and IoT development. Whether you're building simple LED-based projects or more complex systems, the ESP32 offers a versatile platform to bring your ideas to life.