L298N motor driver with Arduino: pinout, wiring and code

The L298N is a dual H-bridge motor driver. It lets an Arduino set the speed and direction of two DC motors, or four wired in pairs, from their own battery. Wire ENA and ENB to PWM pins and IN1–IN4 to any digital pins, join the two boards’ grounds, and pull the ENA/ENB jumper caps off.

The Arduino decides. The L298N does the pushing. It is the one part in this car that can be destroyed by a wiring mistake, and the one whose behaviour most often gets blamed on the code.

L298N pinout

The module has three groups of connections: a screw terminal for power, two screw terminals for the motors, and a row of header pins for the Arduino.

Pin	Group	What it does
+12V	power	motor supply in, 5–35V despite the label
GND	power	ground; must also connect to the Arduino’s GND
+5V	power	5V out from the onboard regulator while the 5V-enable jumper is on
OUT1, OUT2	motor A	one motor, or one side of the car
OUT3, OUT4	motor B	the other motor or side
ENA	control	speed of motor A, from a PWM pin
IN1, IN2	control	direction of motor A
IN3, IN4	control	direction of motor B
ENB	control	speed of motor B, from a PWM pin

Two channels, A and B. This car wires the two left motors in parallel to one channel and the two right motors to the other, which is how one L298N drives four wheels.

Why an Arduino needs a motor driver

An Arduino pin can signal, but it cannot push. A pin supplies roughly 20 milliamps. One of the gear motors in this build wants a few hundred. Wire a motor straight to a pin and you do not get a slow car — you get a dead Arduino.

So the driver sits in between. The battery feeds it directly, and the Arduino only tells it which way and how hard, over six thin signal wires carrying almost no current at all.

How it works, in one paragraph

Inside each half of the board is an H-bridge: four switches arranged in a square with the motor across the middle. Close the top-left and bottom-right pair and current runs through the motor one way. Close the other diagonal and it runs the other way. That is the entire trick behind reverse, and it is why each side needs two direction pins, IN1 and IN2, rather than one.

One wayOther wayBrakeCoast

IN1 HIGH, IN2 LOW. S1 and S4 close. Current runs from the battery through the motor left to right, and it turns one way.

IN1 LOW, IN2 HIGH. The other diagonal, S2 and S3. Current crosses the motor right to left, and it turns the other way.

IN1 and IN2 the same (shown: both LOW, so S3 and S4 close). Both motor leads are tied together. The spinning motor’s own current loops back through it and stops it fast.

ENA at 0. Every switch opens. The motor is cut loose and freewheels to a stop.

IN1	IN2	Motor A
HIGH	LOW	turns one way
LOW	HIGH	turns the other way
LOW	LOW	brakes to a stop
HIGH	HIGH	brakes to a stop

That is with ENA driven. Set ENA to 0 instead and the motor is cut loose and coasts, which is what stopMotors() in the sketch below does. IN3 and IN4 do the same for motor B. Which way counts as “forward” depends only on which way round the motor leads sit in the screw terminal.

Wiring it to the Arduino

Six male-to-female jumper wires, straight across:

Arduino pin	L298N pin	What it does
5	ENA	speed, left side
6	ENB	speed, right side
9	IN4	direction
10	IN3
11	IN2
12	IN1

IN1–IN4 choose direction. ENA and ENB control speed, and they only work on Arduino pins that can do PWM — switching on and off fast enough that the motor averages it out. That is why they sit on pins 5 and 6 rather than anywhere convenient.

The two jumpers, and only one of them matters here

The board ships with small jumper caps on it, and they are not the same jumper. Confusing them is why speed control gets blamed on the sketch.

Powering it

The battery holder’s red lead goes into +12V and black into GND, screwed down. Then the same two leads go across to the Arduino as well:

Battery lead	L298N	Arduino
Red +	+12V	Vin
Black −	GND	GND

That second pair does two jobs at once. It powers the Arduino, so the car does not die the moment you unplug the USB cable. And it gives the two boards a shared ground, which is what lets the driver understand the signals from the six wires above. Without it the wiring looks perfectly correct and nothing works.

Test it: L298N Arduino code

Before the Bluetooth code goes on, prove the driver and the wiring on their own. This sketch uses the exact pins in the table above: it ramps both sides forward from slow to full speed, stops, reverses, stops, and repeats. Lift the car off the table first.

// L298N test: the same pins as the Troniction car.
#define enA 5   // speed, left side  (PWM)
#define enB 6   // speed, right side (PWM)
#define in1 12
#define in2 11
#define in3 10
#define in4 9

void forward() {
  digitalWrite(in1, LOW);  digitalWrite(in2, HIGH);
  digitalWrite(in3, HIGH); digitalWrite(in4, LOW);
}

void backward() {
  digitalWrite(in1, HIGH); digitalWrite(in2, LOW);
  digitalWrite(in3, LOW);  digitalWrite(in4, HIGH);
}

void stopMotors() {
  analogWrite(enA, 0);
  analogWrite(enB, 0);
}

void setSpeed(int speed) {   // 0 to 255
  analogWrite(enA, speed);
  analogWrite(enB, speed);
}

void setup() {
  pinMode(enA, OUTPUT); pinMode(enB, OUTPUT);
  pinMode(in1, OUTPUT); pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT); pinMode(in4, OUTPUT);
  stopMotors();
}

void loop() {
  forward();
  for (int s = 100; s <= 255; s += 5) {   // slow to full speed
    setSpeed(s);
    delay(60);
  }
  delay(1000);
  stopMotors();
  delay(1000);

  backward();
  setSpeed(180);
  delay(2000);
  stopMotors();
  delay(2000);
}

If the ramp at the start does nothing visible and the car goes straight to full speed, the ENA/ENB caps are still on. If one side runs backwards, swap that side’s two leads in its OUT terminal. The full car sketch, with Bluetooth, is step 3 of the build guide.

When it does not work

What you see	Most likely cause
Nothing moves; the red power LED is on	No shared ground between the L298N and the Arduino, or ENA/ENB not connected to pins 5 and 6
Nothing moves; no LED	No power reaching +12V/GND: check the battery switch, the cells, and that the screws are clamping bare wire, not insulation
Motors only ever run at full speed	The ENA/ENB jumper caps are still on
One side runs backwards	That side’s motor leads are swapped in its OUT terminal
Motors hum but do not turn	Speed value too low for the motors to start, or the battery is low; remember the driver takes about 2V first
The Arduino resets when the motors start	The battery sags under load and the Uno browns out; charge the cells
The chip gets hot	Normal in use; this is a lossy driver and the heatsink is there for it

L298N voltage drop: the 2V it takes

An H-bridge is not free. The L298N drops roughly 2V across it, so the motors never see the full pack voltage — with the 7.4V pack in this build they get about 5.4V, which lands neatly inside the TT motors’ 3–6V rating.

That is the real reason this car uses a two-cell pack rather than three. Three 18650s would be 11.1V; take 2V off and the motors would still see around 9V, against a 6V rating. The chassis and gear motors page has the same arithmetic from the motor’s side.

An honest note about the battery

Two 18650 cells are 7.4V nominal, 8.4V fully charged. The Uno’s recommended Vin range is 7–12V, so this car spends its life at the very bottom of that range. It works — the reference car has run this way for years — but it means the Arduino browns out well before the cells are actually flat. If the car starts behaving strangely, charge it before you start debugging it.

Which one to buy

Get the screw-terminal version, around $8. That is the part that keeps this build solder-free: the motor leads and the battery leads land in the terminal block and are tightened with a small Phillips screwdriver. Boards sold without that block need an iron, and there is no soldering anywhere else in this car.

L298N specifications

For the module as it is sold, for reference rather than reading. These are the sellers’ figures, not ST’s: the L298 chip itself is rated to 46V and 4A in total, and the module’s lower 35V ceiling comes from the two 35V capacitors on the board.

Spec	Value
Logic voltage	5V
Drive voltage	5V – 35V
Logic current	0 – 36mA
Drive current	2A max per bridge
Max power	25W
Size / weight	43 × 43 × 27mm, 30g

Download the L298 datasheet if you want STMicroelectronics’ own document, or read the datasheet explained. It covers the chip only; the red module around it has no official datasheet.

Where this fits

Three parts decide how this car behaves: the Arduino Uno makes the decisions, the L298N does the pushing, and the HC-06 listens to your phone. What it pushes is on the chassis and gear motors page, and what powers it on 18650 cells. The wiring itself is step 2 of the build guide; every part has a page, and the whole build is free to read.

Every part of the car