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ESP32 - DC Motor - Limit Switch
In this ESP32 tutorial, we are going to learn how to use ESP32 to control DC motor by limit switch and L298N driver. In detail, we are going to learn:
- How to stop DC motor when a limit switch is touched
- How to change the direction of DC motor when a limit switch is touched
- How to change the direction of DC motor when two limit switches is touched
In this tutorial on ESP32, we'll explore the process of utilizing the ESP32 to manage a DC motor using a limit switch and an L298N driver. Specifically, we'll cover the following aspects:
- Stopping the DC motor upon contact with a limit switch
- Changing the direction of the DC motor upon contact with a limit switch
- Changing the direction of the DC motor when two limit switches are activated
Hardware Used In This Tutorial
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
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Introduction to DC Motor and Limit Switch
If you do not know about DC motor and limit switch (pinout, how it works, how to program ...), learn about them in the following tutorials:
- ESP32 - Limit Switch tutorial
- ESP32 - Controls DC Motor tutorial
Wiring Diagram
This tutorial provides the ESP32 codes for two cases: One DC motor + one limit switch, One DC motor + two limit switches.
- Wiring diagram between the DC motor and a limit switch
This image is created using Fritzing. Click to enlarge image
- Wiring diagram between the DC motor and two limit switches
This image is created using Fritzing. Click to enlarge image
If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.
ESP32 Code - Stop DC Motor by a Limit Switch
The below code make a DC motor spin infinitely and stop immediately when a limit switch is touched
/*
* This ESP32 code is created by esp32io.com
*
* This ESP32 code is released in the public domain
*
* For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-dc-motor-limit-switch
*/
#include <ezButton.h>
#define ENA_PIN 19 // ESP32 pin GPIO19 connected to the IN1 pin L298N
#define IN1_PIN 18 // ESP32 pin GPIO18 connected to the IN2 pin L298N
#define IN2_PIN 17 // ESP32 pin GPIO17 connected to the EN1 pin L298N
ezButton limitSwitch(25); // create ezButton object that attach to pin GPIO25
void setup() {
Serial.begin(9600);
limitSwitch.setDebounceTime(50); // set debounce time to 50 milliseconds
// initialize digital pins as outputs.
pinMode(ENA_PIN, OUTPUT);
pinMode(IN1_PIN, OUTPUT);
pinMode(IN2_PIN, OUTPUT);
digitalWrite(ENA_PIN, HIGH); // max speed
digitalWrite(IN1_PIN, HIGH); // control motor A spins clockwise
digitalWrite(IN2_PIN, LOW); // control motor A spins clockwise
}
void loop() {
limitSwitch.loop(); // MUST call the loop() function first
if (limitSwitch.isPressed()) {
Serial.println(F("The limit switch: TOUCHED"));
digitalWrite(IN1_PIN, LOW); // stop motor
digitalWrite(IN2_PIN, LOW); // stop motor
}
}
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.
- Connect ESP32 to PC via USB cable
- Open Arduino IDE, select the right board and port
- Click to the Libraries icon on the left bar of the Arduino IDE.
- Search “ezButton”, then find the button library by ArduinoGetStarted.com
- Click Install button to install ezButton library.
- Copy the above code and open with Arduino IDE
- Click Upload button on Arduino IDE to upload code to ESP32
- If the wiring is correct, you will see the motor rotates clockwise direction.
- Touch the limit switch
- You will see the motor is stopped immediately
- The result on Serial Monitor looks like below
COM6
The limit switch: TOUCHED
The DC motor is STOPPED
The DC motor is STOPPED
The DC motor is STOPPED
The DC motor is STOPPED
Autoscroll
Clear output
9600 baud
Newline
Code Explanation
Read the line-by-line explanation in comment lines of code!
ESP32 Code - Change Direction of DC Motor by a Limit Switch
The below code make a DC motor spin infinitely and change its direction when a limit switch is touched
/*
* This ESP32 code is created by esp32io.com
*
* This ESP32 code is released in the public domain
*
* For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-dc-motor-limit-switch
*/
#include <ezButton.h>
#define DIRECTION_CCW -1
#define DIRECTION_CW 1
#define ENA_PIN 19 // ESP32 pin GPIO19 connected to the IN1 pin L298N
#define IN1_PIN 18 // ESP32 pin GPIO18 connected to the IN2 pin L298N
#define IN2_PIN 17 // ESP32 pin GPIO17 connected to the EN1 pin L298N
ezButton limitSwitch(25); // create ezButton object that attach to pin GPIO25
int direction = DIRECTION_CW;
void setup() {
Serial.begin(9600);
limitSwitch.setDebounceTime(50); // set debounce time to 50 milliseconds
// initialize digital pins as outputs.
pinMode(ENA_PIN, OUTPUT);
pinMode(IN1_PIN, OUTPUT);
pinMode(IN2_PIN, OUTPUT);
digitalWrite(ENA_PIN, HIGH); // max speed
digitalWrite(IN1_PIN, HIGH); // control motor A spins clockwise
digitalWrite(IN2_PIN, LOW); // control motor A spins clockwise
}
void loop() {
limitSwitch.loop(); // MUST call the loop() function first
if (limitSwitch.isPressed()) {
Serial.println(F("The limit switch: TOUCHED"));
direction *= -1; // change direction
Serial.print(F("The direction -> "));
if (direction == DIRECTION_CW) {
Serial.println(F("CLOCKWISE"));
digitalWrite(IN1_PIN, HIGH); // control motor A spins clockwise
digitalWrite(IN2_PIN, LOW); // control motor A spins clockwise
} else {
Serial.println(F("ANTI-CLOCKWISE"));
digitalWrite(IN1_PIN, LOW); // control motor A spins anti-clockwise
digitalWrite(IN2_PIN, HIGH); // control motor A spins anti-clockwise
}
}
}
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 open with Arduino IDE
- Click Upload button on Arduino IDE to upload code to ESP32
- If the wiring is correct, you will see the motor spins in the clockwise direction.
- Touch the limit switch
- You will see the DC motor's direction is changed to the anti-clockwise
- Touch the limit switch again
- You will see the DC motor's direction is changed to clockwise
- The result on Serial Monitor looks like below
COM6
The limit switch: TOUCHED
The direction -> ANTI-CLOCKWISE
The limit switch: TOUCHED
The direction -> CLOCKWISE
Autoscroll
Clear output
9600 baud
Newline
ESP32 Code - Change Direction of DC Motor by two Limit Switches
The below code make a DC motor spin infinitely and change its direction when one of two limit switches is touched
/*
* This ESP32 code is created by esp32io.com
*
* This ESP32 code is released in the public domain
*
* For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-dc-motor-limit-switch
*/
#include <ezButton.h>
#define DIRECTION_CCW -1
#define DIRECTION_CW 1
#define ENA_PIN 19 // ESP32 pin GPIO19 connected to the IN1 pin L298N
#define IN1_PIN 18 // ESP32 pin GPIO18 connected to the IN2 pin L298N
#define IN2_PIN 17 // ESP32 pin GPIO17 connected to the EN1 pin L298N
ezButton limitSwitch_1(25); // create ezButton object that attach to pin GPIO25
ezButton limitSwitch_2(26); // create ezButton object that attach to pin GPIO26
int direction = DIRECTION_CW;
int prev_direction = DIRECTION_CW;
void setup() {
Serial.begin(9600);
limitSwitch_1.setDebounceTime(50); // set debounce time to 50 milliseconds
limitSwitch_2.setDebounceTime(50); // set debounce time to 50 milliseconds
// initialize digital pins as outputs.
pinMode(ENA_PIN, OUTPUT);
pinMode(IN1_PIN, OUTPUT);
pinMode(IN2_PIN, OUTPUT);
digitalWrite(ENA_PIN, HIGH); // max speed
digitalWrite(IN1_PIN, HIGH); // control motor A spins clockwise
digitalWrite(IN2_PIN, LOW); // control motor A spins clockwise
}
void loop() {
limitSwitch_1.loop(); // MUST call the loop() function first
limitSwitch_2.loop(); // MUST call the loop() function first
if (limitSwitch_1.isPressed()) {
direction *= -1; // change direction
Serial.println(F("The limit switch 1: TOUCHED"));
}
if (limitSwitch_2.isPressed()) {
direction *= -1; // change direction
Serial.println(F("The limit switch 2: TOUCHED"));
}
if (prev_direction != direction) {
Serial.print(F("The direction -> "));
if (direction == DIRECTION_CW) {
Serial.println(F("CLOCKWISE"));
digitalWrite(IN1_PIN, HIGH); // control motor A spins clockwise
digitalWrite(IN2_PIN, LOW); // control motor A spins clockwise
} else {
Serial.println(F("ANTI-CLOCKWISE"));
digitalWrite(IN1_PIN, LOW); // control motor A spins anti-clockwise
digitalWrite(IN2_PIN, HIGH); // control motor A spins anti-clockwise
}
prev_direction = direction;
}
}
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 open with Arduino IDE
- Click Upload button on Arduino IDE to upload code to ESP32
- If the wiring is correct, you will see the motor spins in the clockwise direction.
- Touch the limit switch 1
- You will see the DC motor's direction is changed to anti-clockwise
- Touch the limit switch 2
- You will see the DC motor's direction is changed to clockwise
- The result on Serial Monitor looks like below
COM6
The limit switch 1: TOUCHED
The direction -> ANTI-CLOCKWISE
The limit switch 2: TOUCHED
The direction -> CLOCKWISE
Autoscroll
Clear output
9600 baud
Newline
Video Tutorial
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