🤖 Lesson 4: Obstacle Detection & Avoidance – ELEGOO Smart Robot Car V3

In this lesson, we explore an essential robotics concept: obstacle detection and avoidance using an ultrasonic sensor with the ELEGOO Smart Robot Car V3. By integrating the HC-SR04 ultrasonic module, we program the car to detect obstacles, stop, reverse, and reroute—mimicking intelligent navigation behavior commonly found in autonomous systems.

This tutorial is ideal for learners and developers seeking to understand sensor-based motion logic in embedded robotics. All necessary code is available for download below.

🧠 How It Works – Ultrasonic Sensor

The HC-SR04 ultrasonic sensor emits a sound wave and calculates the distance based on the echo time it receives. It can detect obstacles from a few centimeters up to 4 meters away. In this project, we use the sensor to trigger motor actions when an object comes too close to the front of the robot.

🧪 Demonstration Flow

The video walks through the real-time application of this logic:

• Distance is displayed via serial monitor.

• The robot stops when an obstacle is detected at close range.

• Advanced versions follow the contour of an obstacle or backtrack and redirect intelligently.

🎬 Video Chapters

• 00:00 – Start

• 01:06 – Introduction

• 03:33 – Code: Ultrasonic Distance Sensor Explained

• 07:18 – Demonstration: Measuring Distance

• 07:47 – Obstacle Avoidance and Stop

• 11:39 – Demonstration: Stop at Obstacle

• 13:00 – Code: Follow Obstacle

• 15:40 – Demonstration: Avoid and Reverse

📁 Download Section

The full Arduino code and required wiring diagrams are available below. This lesson is part of the ELEGOO Smart Robot Car series and introduces real-world robotics logic essential for autonomous driving and environmental awareness.