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Home · Module 4 · Build the Raspberry Pi Car

From Pi to autonomous car

Click a GPIO pin to see what it does and what you'd typically wire there for the car project.

Raspberry Pi 4 / 5 — 40-pin GPIO header

Pin detail

Click any pin on the board.

Bill of materials

  • 1× Raspberry Pi (3B+, 4, or 5) + microSD with Raspberry Pi OS
  • 1× L298N H-bridge motor driver
  • 2× DC gear motors with wheels (1:48 ratio typical)
  • 1× HC-SR04 ultrasonic sensor
  • 1× SG90 servo (optional — for sweeping the ultrasonic)
  • 1× 4×AA or 6V battery pack for motors
  • 1× USB power bank for the Pi
  • Jumper wires, breadboard, chassis

Setup steps (Session 9–10)

  1. Flash Raspberry Pi OS Lite onto microSD.
  2. SSH in. Enable GPIO library: pip install RPi.GPIO.
  3. Connect L298N power inputs to battery pack (+/−).
  4. Motor A & B leads → OUT1-2, OUT3-4 on L298N.
  5. L298N IN1-IN4 → 4 Pi GPIOs (direction).
  6. L298N ENA, ENB → 2 Pi PWM-capable GPIOs (speed).
  7. HC-SR04 VCC→5V, GND→GND, TRIG→GPIO, ECHO→GPIO via voltage divider.
  8. Common ground between Pi and motor battery — critical.

Driving the motors (your first script)

import RPi.GPIO as GPIO
import time

# Motor pins
IN1, IN2, IN3, IN4 = 5, 6, 13, 19
ENA, ENB = 12, 18

GPIO.setmode(GPIO.BCM)
for p in [IN1, IN2, IN3, IN4, ENA, ENB]:
    GPIO.setup(p, GPIO.OUT)

pwm_a = GPIO.PWM(ENA, 1000)   # 1 kHz
pwm_b = GPIO.PWM(ENB, 1000)
pwm_a.start(70); pwm_b.start(70)  # 70% duty

def forward():
    GPIO.output(IN1, True);  GPIO.output(IN2, False)
    GPIO.output(IN3, True);  GPIO.output(IN4, False)

def stop():
    for p in (IN1, IN2, IN3, IN4): GPIO.output(p, False)

forward(); time.sleep(2); stop()
GPIO.cleanup()

Once this works, move to the Autonomous Navigation simulator to see what code-driven obstacle avoidance looks like — exactly what you'll port to the car.