In this tutorial, we’ll explore how to work with digital inputs and outputs on the ESP32 using the Arduino IDE. Specifically, you’ll learn how to read the state of a push button and control an LED accordingly.
Why This Tutorial Matters
Understanding how to handle digital inputs and outputs is a fundamental skill for building interactive projects with the ESP32. Whether you're a beginner or looking to brush up on your skills, this guide provides a practical starting point.
Components Needed
To get started, ensure you have the following components:
- ESP32 Board
- 5mm LED
- 330 Ohm Resistor
- Pushbutton
- 10k Ohm Resistor
- Breadboard
- Jumper Wires
Tip: Before proceeding, check out the ESP32 LED Blink Tutorial to familiarize yourself with the basics of the ESP32.
Circuit Assembly
1. Connecting the LED:
- Connect the anode (long leg) of the LED to GPIO 16 on the ESP32.
- Connect the cathode (short leg) to one end of the 330 Ohm resistor.
- Connect the other end of the resistor to the GND (ground) pin on the ESP32.
2. Connecting the Pushbutton:
- Connect one leg of the pushbutton to GPIO 4 on the ESP32.
- The opposite leg of the pushbutton connects to a 10k Ohm pull-down resistor, which is also connected to GND.
- Connect the same leg of the pushbutton (shared with the resistor) to the 3.3V power rail.
Pro Tip: Double-check the connections to ensure the LED and pushbutton are wired correctly. Mistakes in circuit assembly are the most common cause of issues.
Schematic Diagram
Below is the schematic diagram for your circuit:
ESP32 Program Code
Once your circuit is set up, upload the following code to your ESP32 using the Arduino IDE:
// set pin numbers
const int buttonPin = 4; // the number of the pushbutton pin
const int ledPin = 16; // the number of the LED pin
// variable for storing the pushbutton status
int buttonState = 0;
void setup() {
Serial.begin(115200);
// initialize the pushbutton pin as an input
pinMode(buttonPin, INPUT);
// initialize the LED pin as an output
pinMode(ledPin, OUTPUT);
}
void loop() {
// read the state of the pushbutton value
buttonState = digitalRead(buttonPin);
Serial.println(buttonState);
// check if the pushbutton is pressed.
// if it is, the buttonState is HIGH
if (buttonState == HIGH) {
// turn LED off
digitalWrite(ledPin, LOW);
} else {
// turn LED on
digitalWrite(ledPin, HIGH);
}
}Note: The LED is turned on when the button is not pressed due to the pull-down resistor configuration. Pressing the button sends a HIGH signal to GPIO 4, turning the LED off.
Testing Your Project
Once the code is uploaded, it's time to test your setup:
- Press the pushbutton: The LED should turn off.
- Release the pushbutton: The LED should turn on.
If the circuit doesn’t behave as expected:
- Double-check your connections, especially the resistor values.
- Ensure your ESP32 is receiving power and the code was successfully uploaded.
Troubleshooting Tip
If you encounter errors while uploading the code to the ESP32, refer to the How to Solve ESP32 Error in Arduino IDE guide for detailed solutions.
Summary
In this tutorial, you learned how to:
- Connect and configure a pushbutton and an LED to the ESP32.
- Read digital inputs and control digital outputs using the Arduino IDE.
This foundational knowledge unlocks endless possibilities for creating interactive projects. You can now integrate more sensors and actuators, enabling your ESP32 to interact with the environment and perform complex tasks.
What's Next? Experiment by adding more LEDs or buttons to create more intricate control systems!
