L298N motor driver for an Arduino car

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.

Why the car needs one at all

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 the board needs four control pins per side rather than one.

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.

The 2V it takes for itself

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.

The numbers

From the manufacturer’s datasheet, for reference rather than reading:

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 L298N datasheet if you want the manufacturer’s own document.

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