🤖 ALL_IN_ONE_ARDUINO_ROBOT

A Line Follower + Obstacle Avoiding Robot Car Controlled by IR Remote & Mobile App

📌 Introduction

Welcome to the Arduino All-in-One Robot project!
This multipurpose robot combines line following, obstacle avoidance, and remote/mobile control into a single platform. It can be operated using:

🎛️ IR Remote (MP3 remote with custom button mapping)
📱 Android App (built with MIT App Inventor, includes Bluetooth & voice control)

This project is perfect for students, hobbyists, and robotics enthusiasts who want to explore autonomous navigation and interactive control systems.

⚙️ Features

✅ Line Follower Mode – Follows black/white paths using IR sensors
✅ Obstacle Avoidance Mode – Detects and avoids obstacles with ultrasonic sensor
✅ Manual Control – Operated via IR remote or Android app
✅ Voice Commands – Control robot with speech recognition
✅ Speed Control – Adjustable via mobile app slider
✅ DIY Friendly – Easy to assemble with common Arduino components

🧩 Components Required

Component	Quantity
5mm Acrylic Sheet (20cm x 12cm)	1
DC Gear Motor	4
Arduino UNO	1
IR Sensor	2
L298 Motor Driver	1
HC-05 Bluetooth Module	1
IR Receiver Module	1
MP3 Player IR Remote	1
SG90 Servo Motor	1
Ultrasonic Sensor HC-SR04 + Holder	1
Robot Car Wheels	4
Jumper Wires (M-F)	As needed
On/Off Switch	1
18650 Battery Holder (2-cell)	1
18650 Li-ion Battery (3.7V)	2

🔌 Circuit Overview

Power Supply: 2 × 18650 batteries in series (7.4V)
Microcontroller: Arduino UNO
Motor Driver: L298N for left & right motors
Sensors:
- IR sensors → Line following
- Ultrasonic sensor → Distance measurement
Control Modules:
- HC-05 Bluetooth → Mobile app control
- IR Receiver → Remote control
Servo Motor: Rotates ultrasonic sensor for scanning

🎮 Control Mapping

IR Remote

▲ → Move Forward
▼ → Move Backward
▶ → Turn Right
◀ → Turn Left
1 → Manual Mode
2 → Line Follower Mode
3 → Obstacle Avoidance Mode

Mobile App (MIT App Inventor)

Buttons: Forward, Backward, Left, Right, Stop
Voice Commands: “Go Forward”, “Stop”, “Go Back”, “Turn Right”, “Turn Left”
Modes: Line Following, Obstacle Avoidance, Manual
Slider: Adjust robot speed

🎮 Command Mapping Table

App Control (MIT Block)	Data Sent (1‑Byte Number)	Arduino Code Interprets As	Robot Action
Forward (TouchDown)	`1`	`bt_ir_data == 1`	Move Forward
Backward (TouchDown)	`2`	`bt_ir_data == 2`	Move Backward
Left (TouchDown)	`3`	`bt_ir_data == 3`	Turn Left
Right (TouchDown)	`4`	`bt_ir_data == 4`	Turn Right
Stop (manual mode only) / Button Release (TouchUp)	`0`	`bt_ir_data == 0` → Stop (manual mode only)	Stop (manual mode only) Motors
Stop (manual mode only) Button (optional)	`5`	`bt_ir_data == 5`	Stop (manual mode only) Motors
Voice Left	`6`	`bt_ir_data == 6`	Short Left Turn (momentary)
Voice Right	`7`	`bt_ir_data == 7`	Short Right Turn (momentary)
Manual Mode	`8`	`mode = 0`	Switch to Manual Control
Line Follower Mode	`9`	`mode = 1`	Enable Line Following
Obstacle Avoid Mode	`10`	`mode = 2`	Enable Obstacle Avoidance
Slider (Speed Control)	`21–255`	`Speed = data`	Adjust Motor Speed (PWM)

📱 Mobile App Setup

Install the provided APK on your Android device
Or import the AIA file into MIT App Inventor to customize
Connect via Bluetooth (HC-05) → Default pairing code usually 1234 or 0000

🛠️ Arduino Setup

Install Arduino IDE
Install IRremote (the sketch uses its v3-style IrReceiver API) and Servo; SoftwareSerial is supplied by the Arduino AVR core
Select Arduino UNO board & correct COM port
Upload the provided .ino code
Power the robot and test each mode

Pinout and firmware states

The table follows AIOR.ino; confirm the physical wiring against schematic.png before connecting power.

Connection	Arduino Uno pin
HC-05 TX → Uno software RX	D2
Uno software TX → HC-05 RX	D3 (use a suitable logic-level divider)
L298N right enable / IN1 / IN2	D10 / D9 / D8
L298N left enable / IN3 / IN4	D5 / D7 / D6
Right / left line sensor	A0 / A1
HC-SR04 echo / trigger	A2 / A3
Scanning servo signal	A4
IR receiver signal	A5

Bluetooth and USB diagnostic serial both use 9600 baud. Motor power must use the driver supply; connect controller, sensor and driver grounds together.

There are three firmware states. Voice turns (6 and 7) are actions within manual control.

stateDiagram-v2
    [*] --> Manual
    Manual --> LineFollower: byte 9
    Manual --> ObstacleAvoid: byte 10
    LineFollower --> Manual: byte 8
    LineFollower --> ObstacleAvoid: byte 10
    ObstacleAvoid --> Manual: byte 8
    ObstacleAvoid --> LineFollower: byte 9

The IR button labels vary by remote. The firmware maps raw 0xFF30CF to manual, 0xFF18E7 to line following and 0xFF7A85 to obstacle avoidance. Use the serial output to check your remote's codes; the app's byte table above is the firmware contract.

Limitations before a moving test

The servo helper now normalizes the step sign. The descending 140 → 0 startup/scan calls previously increased the angle instead of completing.
Turns and scanning use blocking delays. Bytes 0/5 stop the motors only in manual mode. Autonomous modes ignore those stop bytes; send byte 8 to return to manual and stop once input polling resumes. There is no independent emergency-stop or lost-connection timeout.
A missing ultrasonic echo returns 400 cm. Obstacle mode treats that as clear space and can drive forward; it cannot distinguish a disconnected sensor from an out-of-range obstacle.
On a classic ATmega328P Uno, the Servo library uses Timer1, which conflicts with PWM on D9/D10. The right motor enable is D10. This requires a reviewed wiring/timer change before relying on independent motor speed control; this update does not change the pinout.
Selecting line-following or obstacle mode sets its default speed again while the mode-select command remains the last command. Slider behavior therefore needs a device check in each mode.

For initial checks, lift the wheels clear of the surface and keep motor power easy to disconnect. The host regression check verifies the servo angle sequence only:

# Python 3 and g++ required; no Arduino board connected.
python3 -m unittest discover -s tests -v

Firmware upload, motor polarity, sensor thresholds, IR decoding and timing still require the physical build. The configured scan is 70 → 140 → 0 → 70, rather than a full 180-degree sweep.

🧪 Hardware Testing

Calibrate IR sensors for black/white surface detection
Test IR remote buttons for movement & mode switching
Verify Bluetooth connection with mobile app
Test voice commands and speed control

📷 Demo & Media

Robot Car Build

🎥 Full Demo on YouTube

📚 Learning Outcomes

Understanding of autonomous navigation
Integration of sensors, actuators, and wireless modules
Hands-on experience with Arduino programming
Exposure to MIT App Inventor mobile app development

✅ Conclusion

The sketch, App Inventor source, APK, schematic and build photos are included. Use the pinout and limitations above when adapting the build; the photos and demo are separate from the host regression check.

📜 License

This project is licensed under the Apache License 2.0 – see the LICENSE file for details.

Name		Name	Last commit message	Last commit date
docs		docs
tests		tests
.gitattributes		.gitattributes
.gitignore		.gitignore
AIOR.aia		AIOR.aia
AIOR.apk		AIOR.apk
AIOR.ino		AIOR.ino
LICENSE		LICENSE
README.md		README.md
schematic.png		schematic.png

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🤖 ALL_IN_ONE_ARDUINO_ROBOT

📌 Introduction

⚙️ Features

🧩 Components Required

🔌 Circuit Overview