SENSORS/ACTUATORS

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ESP32 - DC Motor

This tutorial instructs you how to use ESP32 to control DC motor using L298N Motor Driver. In detail, We will learn how to control the speed and direction of DC motor. We will learn how to control a single DC motor, and then two DC motors using a single L298N motor driver.

Hardware Used In This Tutorial

1	×	ESP-WROOM-32 Dev Module
1	×	USB Cable Type-C
1	×	L298N Motor Driver Module
1	×	5V DC Motor
1	×	5V Power Adapter for 5V DC motor
1	×	Breadboard
1	×	Jumper Wires
1	×	(Optional) DC Power Jack
1	×	(Recommended) ESP32 Screw Terminal Adapter

Or you can buy the following sensor kit:

DIYables Sensor Kit 30 types, 69 units

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Introduction to DC Motor

DC Motor Pinout

A DC Motor includes two wires: Negative(black), and Positive(red)

How DC Motor Works

The direction and speed of DC motor will be determined by how we provide power to it. The below images how the detaied relation between power and speed/direction

In the case of using PWM, there bigger duty cycle The PWM is, the bigger speed the montor spins.

How to control speed and direction of DC motor using ESP32

Firstly, The DC motor works with high voltage that can burn ESP32 ⇒ We cannot connects DC motor directly to ESP32. We need a hardware driver between DC motor and ESP32. The driver takes three responsibilities:

Protecting ESP32 from the high voltage
Receiving the signal from ESP32 to change the pole of power supply to control the motor's direction.
Amplifying the PWM signal from ESP32 (current and voltage) to control the motor's speed

There are a lot of DC motor drivers. This tutorial will use the L298N driver.

Introduction to L298N Driver

A single L298N driver can control two DC motors or a stepper motor. This tutorial uses this driver to control the DC motor.

L298N Driver Pinout

The below image shows the L298N driver's pinout.

The detailed explanation for each pin is avaialble in this Arduino - DC motor tutorial

A single L298N driver can control two DC motor independently:

The first motor (called motor A) is controlled by IN1, IN2, ENA, OUT1, OUT2 pins.
The second motor (called motor B) is controlled by IN3, IN4, ENB, OUT3, OUT4 pins.

How To Control the Speed of DC Motor via L298N Driver

It is simple to control the speed of the DC motor by generating a PWM signal to the ENA/ENB pin of L298N. We can do this by:

Connecting an ESP32's digital output pin to L298N's ENA/ENB pin
Creating a PWM signal to the ENA/ENB pin by using analogWrite() function. This PWM signal goes though L298N Driver and amplified current and voltage before going to to the DC motor

analogWrite(PIN_ENA, speed); // control motor A analogWrite(PIN_ENB, speed); // control motor B

The speed is a value between 0 and 255. If it is 255, the motor runs at maximum speed. If it is 0, the motor stops.

How To Control the Direction of DC Motor via L298N Driver

The DC motor A's direction can be controlled by IN1 and IN2 pins. The following table shows the rekation between the motor's direction and signal on IN1 and IN2 pins.

IN1 pin	IN2 pin	Direction
HIGH	LOW	DC Motor A rotates in clockwise direction
LOW	HIGH	DC Motor A rotates in anticlockwise direction
HIGH	HIGH	DC Motor A stops
LOW	LOW	DC Motor A stops

Similarly, The below table is for DC motor B

IN3 pin	IN4 pin	Direction
HIGH	LOW	DC Motor B rotates in clockwise direction
LOW	HIGH	DC Motor B rotates in anticlockwise direction
HIGH	HIGH	DC Motor B stops
LOW	LOW	DC Motor B stops

Let's learn how to program to control it. Let's take the motor A for example. The motor B is similar.

Controling the motor A dirrection to clockwise

digitalWrite(PIN_IN1, HIGH); digitalWrite(PIN_IN2, LOW);

Controlingthe motor A dirrection to anti-clockwise

digitalWrite(PIN_IN1, LOW); digitalWrite(PIN_IN2, HIGH);

※ NOTE THAT:

The DC motor's direction is opposite if the wiring between DC motor and L298N driver is in reverse order. In that case, swap OUT1 and OUT2 pins.

How To Stop DC Motor

There are two ways to stop a DC motor

Controlling the speed to 0

analogWrite(PIN_ENA, 0);

Controlling IN1 IN2 pins to the same LOW or HIGH

digitalWrite(PIN_IN1, HIGH); digitalWrite(PIN_IN2, HIGH);

digitalWrite(PIN_IN1, LOW); digitalWrite(PIN_IN2, LOW);

How to control a DC motor using L298N driver.

Wiring Diagram

There are three jumpers on the L298N module. Remove all of them before doing the wiring.

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

Let's see the below code that does the foloowing thing one by one:

ESP32 controls the DC motor's speed increasingly.
ESP32 inverts the DC motor's direction
ESP32 controls the DC motor's speed decreasingly.
ESP32 stops the DC motor

/* * 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 */ #define PIN_IN1 19 // ESP32 pin GPIO19 connected to the IN1 pin L298N #define PIN_IN2 18 // ESP32 pin GPIO18 connected to the IN2 pin L298N #define PIN_ENA 17 // ESP32 pin GPIO17 connected to the EN1 pin L298N // the setup function runs once when you press reset or power the board void setup() { // initialize digital pins as outputs. pinMode(PIN_IN1, OUTPUT); pinMode(PIN_IN2, OUTPUT); pinMode(PIN_ENA, OUTPUT); } // the loop function runs over and over again forever void loop() { digitalWrite(PIN_IN1, HIGH); // control the motor's direction in clockwise digitalWrite(PIN_IN2, LOW); // control the motor's direction in clockwise for (int speed = 0; speed <= 255; speed++) { analogWrite(PIN_ENA, speed); // speed up delay(10); } delay(2000); // rotate at maximum speed 2 seconds in clockwise direction // change direction digitalWrite(PIN_IN1, LOW); // control the motor's direction in anti-clockwise digitalWrite(PIN_IN2, HIGH); // control the motor's direction in anti-clockwise delay(2000); // rotate at maximum speed for 2 seconds in anti-clockwise direction for (int speed = 255; speed >= 0; speed--) { analogWrite(PIN_ENA, speed); // speed down delay(10); } delay(2000); // stop motor 2 second }

Quick Instructions

If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
Remove all three jumpers on the L298N module.
Copy the above code and paste it to Arduino IDE.
Compile and upload code to ESP32 board by clicking Upload button on Arduino IDE
Watch the DC motor, You will see:

DC motor is accelerated and spins at the maximum speed during 2 second
DC motor's direction is reversed
DC motor spins in the reverse direction at the maximum speed during 2 seconds
DC motor is decelerated
DC motor stop 2 second

The above process is repeated infinitely.

※ NOTE THAT:

This tutorial instructs you how to control the DC motor speed relatively. To control the absolute speed (round per second), it needs to use a PID controller and the feedback from an encoder.

How to Control two DC Motors using L298N Driver

(coming soon)

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