Controlling Two DC Motors With L293D IC

Controlling Two DC Motors With L293D IC

What is a Motor Driver?

A motor driver helps to control the speed of the motor with a small current which is amplified to a higher current signal. Motor driver inputs as low current signal and gives higher current. There are many motor driver ICs, L293D, L298N are most popular. These driver helps to control two DC motors.

Why do Motor Drivers need?

In automation system, DC motors are frequently used in robotics to control movement. Microprocessors or microcontrollers help to control those motors. Microprocessors or microcontrollers require a small amount of current and operate at low voltage, whereas motor needs higher current and voltage. Again, current is not supplied from the controllers. So, it needs external power supply to control the motors. And there needs a motor driver to control high and low voltages of those motors.

L293D motor driver

Now let’s talk about L293D motor driver. It is a Dual H-Bridge Motor driver. It receives signals from the controller and transmits to the motor to motors. There are two voltage pins in the IC where one is used to draw current for the working of the motor driver and another one is used to apply voltage to the motors. The L293D switches it output signal according to the input received from the controller.

It is an easy way to double the current capacity by using two ICs connected in parallel. There is some shield found on the market for these. In general, two ICs put in parallel so voltage remains the same but current doubles. L293D ICs are rated at about 600 mA and 1.2 A for a certain time. After parallel connection, it will handle 1.2A continuously and 2.4A for certain time.

The L293D is a 16 pin IC, with eight pins on both sides. Two motors can be controlled. There are 2 INPUT pins, 2 OUTPUT pins and 1 ENABLE pin for each motor. L293D consist of two H-bridge. H-bridge is the well-known process to control a low current rated motor.

H-bridge is a circuit which allows the voltage to be flown in either direction. In above diagram, the arrow on the left points to the higher potential side of the input voltage of the circuit. Now if the switches S1 & S4 are kept in a closed position while the switches S2 & S3 are kept in an open position meaning that the circuit gets shorted across the switches S1 & S4. This creates a path for the current to flow, starting from the V input to switch S1 to the motor, then to switch S4 and then the exiting from the circuit. This flow of the current would make the motor turn in one direction. One can get it to turn the motor in the opposite direction by simply changing the terminals.

To control two DC
motors, it may use L293D motor driver with Arduino microcontroller. Here, Arduino is used as microcontroller. The main equipment list is given below-

• L293D Motor Driver.
• Arduino UNO.
• DC motors.
• Bread Board.
• 9V Battery.
• Jumper Wires.
• Wheels

Connect the circuit according to the diagram. Add wheels if needed. We can use enable pins to control the rotating speed of the motor. Otherwise, enable pins need to connect to the 5volt. So, motors will get maximum power and rotate at its top speed on that voltage. All ground pins should be connected to a common point, but it is not mandatory. All symmetric diagrams are given below.

Now connect the Arduino
wire with it and upload the given code. The motors will start running according to the code’s direction.