ESP32 Tutorial – Limit Switch

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ESP32 Tutorial - Limit Switch
Contents hide
1 Introduction
2 Hardware Components
3 Steps-by-Step Guide

Introduction

Interfacing and controlling a limit switch with an ESP32-WROOM microcontroller involves connecting the limit switch to one of the GPIO pins on the ESP32-WROOM and monitoring the switch for any changes in its state. in today’s tutorial, we are going to understand how to interface a simple limit switch with an ESP32-WROOM microcontroller.

What is a Limit Switch?

A limit switch is an electromechanical device that utilizes a mechanical actuator, such as a plunger, lever, or roller, to mechanically actuate electrical contacts. Limit switches operate based on mechanical displacement and find applications in position sensing, safety systems, and automation control.

Hardware Components

To interface a Limit Switch with ESP32, you’ll need the following hardware components to get started:

ComponentsValue / ModelQty
ESP32–1
Limit Switch–1
Breadboard–1
Jumper Wires–1
DC Power for ESP32–1

Steps-by-Step Guide

(1) Setting up Arduino IDE

Download Arduino IDE Software from its official site. Here is a step-by-step guide on “How to install Arduino IDE“.

(2) ESP32 in Arduino IDE

There’s an add-on that allows you to program the ESP32 using the Arduino IDE. Here is a step-by-step guide on “How to Install ESP32 on Arduino IDE“.

(3) Include Libraries

Before you start uploading a code, download and unzip the ezButton.h library at /Program Files(x86)/Arduino/Libraries (default). Here is a step-by-step guide on “How to Add Libraries in Arduino IDE“.

(4) Schematic

Make connections according to the circuit diagram given below.

Wiring / Connections

ESP32Limit Switch
GNDGND
GIOP17Pin 2

(5) Uploading Code

Now copy the following code and upload it to Arduino IDE Software.

Much like a button or switch, a Limit Switch also demands debouncing. This can introduce complexity into the code structure. Nonetheless, the ezButton library simplifies this by providing debouncing capabilities and leveraging internal pull-up registers, thus facilitating programming tasks.

#include <ezButton.h>

ezButton limitSwitch(17);  // create ezButton object that attach to ESP32 pin GIOP17

void setup() {
  Serial.begin(9600);
  limitSwitch.setDebounceTime(50); // set debounce time to 50 milliseconds
}

void loop() {
  limitSwitch.loop(); // MUST call the loop() function first

  if(limitSwitch.isPressed())
    Serial.println("The limit switch: UNTOUCHED -> TOUCHED");

  if(limitSwitch.isReleased())
    Serial.println("The limit switch: TOUCHED -> UNTOUCHED");

  int state = limitSwitch.getState();
  if(state == HIGH)
    Serial.println("The limit switch: UNTOUCHED");
  else
    Serial.println("The limit switch: TOUCHED");
}

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