Project 1: Control two DC motors with your Arduino and the L298N controller

In this article you will learn how to control two 5V DC motors with your Arduino.

To enable the Arduino to safely control the motors, you will use the L298N motor controller module.

I will be using two geared DC motors from a toy tank that I stole from my kids (they originally stole it from me).

The DC motor controller module

Even though you could connect a small DC motor directly to the Arduino, it is not a good idea.

The Arduino can only provide a very small amount of current to external devices. Only the tiniest of motors would be satisfied with that.

In virtually all real-life applications, you should provide external power to the motor.

To do this, I am going to use a popular motor driver module that contains the L298N motor driver “bridge”. This integrated circuit (IC) can provide enough current to our motors, so we can use them in power-hungry applications. The L298N IC can't be used on its own. It requires several other components to operate properly, such as capacitors and diodes, a heatk sink etc.

Therefore, it is convenient to use a module that contains the L298N and all of the required components on a single board, like as the one in this image below.

Project parts list

1. Two 5V DC motors. 
2. An Arduino Uno.
   
3. A motor controller module with the L298N chip.
   
4. One AA-battery pack with 4 batteries.
   
5. A bunch of jumper wires.
   

Follow these instructions to make the connections and build your circuit. Refer to the annotated photograph of the L298N module above for the pin names.

Start by unplugging the Arduino from your computer so that it is not in operation.

1. Connect the first motor to motor controller module Out1 and Out2. The order does not matter.
2. Connect the first motor to motor controller module Out3 and Out4. The order does not matter.
   
3. Connect the positive wire from the battery pack to pin +12V on the module.
   
4. Connect the negative wire from the battery pack to pin GND on the module.
   
5. Connect the GND pin of the module to the GND pin of the Arduino.
   
6. Connect Arduino pin 5 to module pin In1.
   
7. Connect Arduino pin 4 to module pin In2.
   
8. Connect Arduino pin 3 to module pin In3.
   
9. Connect Arduino pin 2 to module pin In4.
   
10. Inspect the wiring and ensure they are correct.
    

And here’s what the assembled circuit looks like:

Let's look at the role of each pin in the motor controller module.

In1 and In3 control the direction of spin for motor 1 and motor 2 respectively.

In2 and In4 control the speed for each motor.

Finally, pin "GND" is for ground, and should be connected to one of Arduino’s GND pins so that both the Arduino and the module share the same ground voltage level.

Here’s the sketch for Demo 1:

//Arduino PWM Speed Control：

int E1 = 5;
int M1 = 4;
int E2 = 6;                    
int M2 = 7;                       

void setup()
{
    pinMode(M1, OUTPUT);  
    pinMode(M2, OUTPUT);
}

void loop()
{
  int value;
  for(value = 0 ; value <= 255; value+=1)
  {
    digitalWrite(M1,HIGH);  
    digitalWrite(M2,HIGH);      
    analogWrite(E1, value);   //PWM Speed Control
    analogWrite(E2, value);   //PWM Speed Control
    delay(30);
  }
}

Every time that the block in this loop runs, we first set the direction of spin for both motors by writing a HIGH value to pins M1 and M2 (Arduino pins 4 and 7 respectively),  and then we set the spin by using the PWM function analogWrite. The value we write to these pins is controlled by the “for” loop.

If you would like to learn how to use DC motors with your Arduino, consider enrolling to Arduino Step by Step Getting Serious.

We have a full section (Section 16) with 10 lectures dedicated to this topic.