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Arduino Code and Video: L293D DC Motor Controller (without speed control)

This tutorial covers how to use the L293D motor controller with an Arduino to control a DC motor. The L293D allows you to rotate the motor in both clockwise and counter-clockwise directions. By following this guide, you'll learn how to wire the components and program the Arduino to achieve the desired motor control.

In this project, we will utilize the L293D motor driver to control a single DC motor. The motor will be able to switch directions based on the commands given in the Arduino code. For a clearer understanding of the setup and code, it's beneficial to watch the associated video (in video at 00:00).

Hardware Explained

The L293D is an integrated circuit designed for driving motors. It can control two DC motors simultaneously or one stepper motor. The chip uses an H-bridge configuration to allow for direction control by switching the polarity of the voltage applied to the motor. This flexibility makes it an excellent choice for robotics and automation projects.

In addition to the L293D, we will be using an Arduino board to send control signals to the motor driver. The Arduino will generate the necessary logic levels to enable the motor and determine its rotation direction. The setup will also require a DC motor and a power supply compatible with the motor's voltage requirements.

Datasheet Details

• Ensure the supply voltage does not exceed 36 V.
• Use appropriate heat-sinking when operating near maximum current.
• Always connect the ground of the Arduino and the motor driver.
• Check the wiring to avoid reversed polarity connections.
• Use PWM signals to control speed if required in future projects.

Wiring Instructions

To wire the L293D motor controller to the Arduino, start by connecting the power and ground. Connect the L293D's pin 4 and pin 5 to the ground. Then, connect pin 1 (Vcc1) to the 5 V output of the Arduino. For Vcc2 (pin 8), connect it to an external power supply, ensuring it matches the motor voltage specification.

Next, connect the enable pin (pin 1) to pin 8 on the Arduino to control the motor's power. For the motor control inputs, connect pin 2 (1A) of the L293D to pin 2 on the Arduino and pin 7 (2A) to pin 7 on the Arduino. Finally, connect the motor terminals to pin 3 (1Y) and pin 6 (2Y) on the L293D.

Code Examples & Walkthrough

The following code initializes the pins and sets up the motor control. The identifiers used include P1A for the first motor control pin and EN12 for the enable pin. The setup function configures the pins as outputs.

void setup() {
  Serial.begin(9600); // setup Serial Monitor to display information
  pinMode(P1A, OUTPUT); // define pin as OUTPUT for P1A
  pinMode(P2A, OUTPUT); // define pin as OUTPUT for P2A
  pinMode(EN12, OUTPUT); // define pin as OUTPUT for 1,2EN enable
}

In the loop, the motor is commanded to rotate in both directions with delays in between. The state of the motor is printed to the serial monitor using Serial.println.

void loop() {
  Serial.println("Rotating CW");
  digitalWrite(EN12, HIGH); // Enable 1A and 2A 
  digitalWrite(P1A, HIGH); // send HIGH signal to P1A
  digitalWrite(P2A, LOW); // send LOW signal to P2A
  delay(3000); // motor runs for 3 seconds
  digitalWrite(EN12, LOW); // Disable 1A and 2A
}

This excerpt shows how to control the motor's rotation direction by changing the logic levels sent to P1A and P2A. The motor runs for 3 seconds before stopping and switching directions.

Here is how L293D half bridge drivers used:

Demonstration / What to Expect

When the setup is complete and the code is uploaded, you should observe the motor rotating in one direction for 3 seconds, stopping for 2 seconds, and then rotating in the opposite direction for another 3 seconds. The state of the motor will be printed on the serial monitor, confirming the actions (in video at 12:00).

Common pitfalls include ensuring the correct voltage is supplied to the motor and verifying that the motor connections are correct. If the motor does not respond, double-check the wiring and the power supply connections.

Video Timestamps

• 00:00 - Introduction
• 02:30 - Wiring explanation
• 05:00 - Code walkthrough
• 10:00 - Demonstration of motor control

Images

L293D breadboard pin 1

L293D_breadboard_wiring_bb

L293D as halft bridge CCW

L293D as halft bridge CW

Arduino wiring for L293D motor driver with battery

Arduino wiring for L293D motor driver

L293D breadboard pin 1

L293D_breadboard_wiring_bb

L293D as halft bridge CCW

L293D as halft bridge CW

Arduino wiring for L293D motor driver with battery

Arduino wiring for L293D motor driver