ESP32 - Button - Relay

This tutorial instructs you how to use ESP32 to control LED based on the pressing state of button. In detail:

We also have another tutorial: ESP32 - Button Toggles Relay, which toggle relay's state between ON and OFF when the button is pressed.

We can extend this tutorial to use button to control a led strip, siren, light bulb, or motor... by connnecting them to the relay.

Hardware Used In This Tutorial

1×ESP-WROOM-32 Dev Module
1×Micro USB Cable
1×Warning Light Bright Waterproof
1×12V Power Adapter
1×Jumper Wires
1×(Optional) 5V Power Adapter
1×(Optional) DC Power Jack
1×(Optional) ESP32 Screw Terminal Adapter

One of the following breadboard:

1×Full-sized 830-Point Breadboard
1×Half-sized 400-point Breadboard
1×Mini-sized 170-point Breadboard
1×All-sized Breadboard Kit
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Introduction to Relay and Button

We have specific tutorials about relay and button. Each tutorial contains detailed information and step-by-step instructions about hardware pinout, working principle, wiring connection to ESP32, ESP32 code... Learn more about them at the following links:

Wiring Diagram between ESP32, Relay and Button

ESP32 Button Relay Wiring Diagram

This image is created using Fritzing. Click to enlarge image

ESP32 Code

/* * This ESP32 code is created by * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit */ #define BUTTON_PIN 22 // ESP32 pin GIOP22 connected to button's pin #define RELAY_PIN 27 // ESP32 pin GIOP27 connected to relay's pin void setup() { Serial.begin(9600); // initialize serial pinMode(BUTTON_PIN, INPUT_PULLUP); // set ESP32 pin to input pull-up mode pinMode(RELAY_PIN, OUTPUT); // set ESP32 pin to output mode } void loop() { int buttonState = digitalRead(BUTTON_PIN); // read new state if (buttonState == LOW) { Serial.println("The button is being pressed"); digitalWrite(RELAY_PIN, HIGH); // turn on } else if (buttonState == HIGH) { Serial.println("The button is unpressed"); digitalWrite(RELAY_PIN, LOW); // turn off } }

Quick Instructions

  • If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
  • Do the wiring as above image.
  • Connect the ESP32 board to your PC via a micro USB cable
  • Open Arduino IDE on your PC.
  • Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
  • Copy the above code and paste it to Arduino IDE.
  • Compile and upload code to ESP32 board by clicking Upload button on Arduino IDE
Arduino IDE Upload Code
  • Press and keep pressing the button several seconds
  • See the change on the relay's state

Line-by-line Code Explanation

The above ESP32 code contains line-by-line explanation. Please read the comments in the code!

Video Tutorial

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