This document describes the components, working, circuit, source code, and scope of an obstacle avoidance robot powered by an Arduino. The main components are a chassis, Arduino UNO microcontroller, DC motor, motor driver, ultrasonic sensor, and servo motor. The robot uses the ultrasonic sensor to calculate distances and detects obstacles. It then controls the DC motor and servo motor using the motor driver and Arduino to avoid obstacles and navigate autonomously. The source code contains functions for movement, distance calculation, and sensor control. Potential applications discussed for further development include using it as a firefighting, mining, driverless vehicle, or cleaning robot.

1. Obstacle
Avoidance Robot
Powered by Arduino

2. CircuitComponents Working Source Code Scope

3. Components

4. Components /
1. Chassis 2. Arduino UNO 3. DC Motor
4. Motor Driver 6. Servo Motor5. Ultrasonic Sensor

5. Components /
1. Chassis
• Good quality robotic chassis for DIY
projects
• Laser cut super smooth double layer
acrylic chassis
• Contains Ultrasonic Sensor and Servo
Motor holder

6. Components /
2. Arduino UNO
Microcontroller ATmega328P
Operating Voltage 5V
Input Voltage 7-12V (recommended)
6-20V (limit)
Digital I/O Pins 14
PWM Digital I/O Pins 6
Analog Input Pins 6
SRAM 2 KB (ATmega328P)
EEPROM 1 KB (ATmega328P)
BUILTIN LED 13
Dimension 68.6 mm X 53.4 mm
Weight 25g

7. Components /
2. Arduino UNO
Open Source Hardware: Schematics
• Arduino Uno is open-source hardware! You
can build your own board
Programming
• The UNO is the best board to get started with
electronics and coding
• The Arduino Uno can be programmed with
the Arduino Software IDE
Power
• The Arduino Uno board can be powered via
the USB connection or with an external
power supply from 6 to 20 volts. The power
source is selected automatically

8. Components /
3. DC Motor
Voltage 3-6V DC
Reduction Ratio 1:48
Maximum torque 800k.cm
Material Plastic
Weight 2.4 ounces
Load Current 70mA (250mA MAX)
No-load Speed 1:48 (3V)

9. Components /
4. L298N Motor Driver
Driver Dual H Bridge Motor Driver IC
Operating
Voltage
7 to 35V
Peak Current 2A
Max Power
Consumption
20W (When the temperature
T = 75 °C
Weight 33g

10. Components /
5. HC-SR04 Ultrasonic Sensor
Operating Voltage 5V
Theoretical Measuring
Distance
2cm to 450cm
Practical Measuring
Distance
2cm to 80cm
Measuring Angle
Covered
<15°
Operating Current <15mA
Operating Frequency 40Hz

11. Components /
6. SG90 Micro Servo Motor
Operating Voltage 5V
Torque 2.5kg/cm
Operating Speed 0.1s/60°
Gear Type Plastic
Rotation 0°-240°
Weight 9g

12. Working

13. Working /
1. Calculating the Distance
• Ultrasonic signals travel at the speed of sound
• At 20°C the speed of sound is 343 m/s
• Time measured by HC-SR04 is for return trip
• Divide time in half to calculate distance
𝐷 = (Δt/2) × 𝑐
Δt = Time Delay
C = Speed of Sound
D = Distance Measured

14. Working /
2. Controlling the Speed and Direction of DC Motor
Motor A Enable:
• 5Volts = Enabled
• Ground = Disabled
• PWM = Speed Control
Motor A:
• Input 1: 5 Volts = Forward
• Input 2: Ground = Forward
Motor A:
• Input 1: Ground = Reversed
• Input 2: 5 Volts = Reversed
*Motor B Inputs work the same way
Pulse Width Modulation (PWM)

15. Working /
3. Using Servo Motor to Rotate Ultrasonic Sensor
• SG90 Micro Servos use DC motors
• Potentiometer is used as feedback sensor
• Internal controller board monitors and adjust position
• Position controlled using Pulse Width Modulation (PWM)
Torque
• Amount of force servo can apply to a lever
• Measured in kilogram centimetres (kg-cm)
• Rated Torque: 2.5 kg-cm

16. Circuit

17. Circuit /
Obstacle Avoidance Robot Schematic

18. Source
Code

19. Source Code </> /
Move Forward Function

20. Source Code </> /
Move Backward Function

21. Source Code </> /
Turn Right Function

22. Source Code </> /
Turn Left Function

23. Source Code </> /
Move Stop Function
Distance Calculator Function

24. Source Code </> /
Look Right Function
Look Left Function

25. Source Code </> /
Pin Declaration

26. Source Code </> /
Arduino Setup Code

27. Source Code </> /
Arduino Loop Code

28. Scope

29. Scope /
Further Improvements and Future Scope
1. Adding a Camera
• If interfaced with a camera, robot can be driven beyond line of sight
• Range becomes practically unlimited as network have a large range
2. Use as a fire fighter robot
• Addition of temperature sensor, water tank required
• Required some changes in programming
• It can work as an autonomous fire extinguisher
3. Obstacle detection for a Mining Vehicle
4. Driverless vehicles running along beams
5. Obstacle detecting system for a motor vehicle
6. Autonomous cleaning robot

30. Thank You