🤖 Robot Line Follower

6 TCRT5000 Sensors + PID Control — Arduino Uno R3

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📋 Overview

An autonomous line-following robot built on Arduino Uno R3. Uses 6 IR sensors (TCRT5000) for precise line detection and a PID controller for smooth, high-speed path tracking. Suitable for robotics competitions and educational projects.

Features

Feature	Description
6‑Sensor Array	Wide detection range, handles sharp turns & zigzags
PID Tracking	Configurable Kp/Ki/Kd for track-specific tuning
Auto‑Calibration	~5‑second calibration on every startup
Line‑Lost Recovery	Progressive search: head toward last known side → reverse → spin
Intersection Detection	All sensors black → go straight automatically
Serial Debug	Real‑time position, error, and sensor status output

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🧰 Hardware

Component	Quantity	Notes
Arduino Uno R3	1	Or any ATmega328P board
TCRT5000 IR Sensor	6	Reflective optical sensor
L298N Motor Driver	1	Dual H‑bridge
DC Motor (w/ wheel)	2	3‑6V, ~100 RPM
Caster Ball	1	Free‑rotating front support
Li‑Po / Li‑Ion Battery	1	7.4V recommended
Acrylic / ABS Chassis	1	Custom or generic line‑follower chassis

Wiring

   TCRT5000 Array         Arduino Uno            L298N
  ┌────────────────┐     ┌───────────┐      ┌────────────┐
  │ Sensor 0 (left)│────▶│ A0        │      │            │
  │ Sensor 1       │────▶│ A1        │      │  ENA ▶ 5   │
  │ Sensor 2       │────▶│ A2        │      │  IN1 ▶ 8   │
  │ Sensor 3       │────▶│ A3        │      │  IN2 ▶ 9   │
  │ Sensor 4       │────▶│ A4        │      │  IN3 ▶ 10  │
  │ Sensor 5 (right)│───▶│ A5        │      │  IN4 ▶ 11  │
  └────────────────┘     │           │      │  ENB ▶ 6   │
                         │           │      └────────────┘
                         └───────────┘

(See spesifikasi.txt for full detail.)

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🚀 Getting Started

1. Install Arduino IDE

Download from arduino.cc.

2. Open the sketch

File → Open → ard/code/line_follower.ino

3. Upload

1. Connect your Arduino via USB.
2. Select board: Tools → Board → Arduino Uno.
3. Select port: Tools → Port → /dev/ttyUSB0 (Linux) or COM3 (Windows).
4. Click → (Upload).

4. Run

Place the robot on a black line on a white surface and power it on. The robot calibrates for 5 seconds, then starts tracking automatically.

⚠️ Calibration note: During calibration, move the robot so each sensor sees both the black line and the white surface. This ensures proper threshold detection.

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⚙️ Tuning

PID Constants

Default values (good starting point for 18‑25 mm black line on white):

Parameter	Default	Range	Effect
KP	25	10–100	Reactivity to line deviation
KI	0	0–50	Steady‑state error correction
KD	15	0–50	Dampens oscillation

Tuning tip: If the robot oscillates → lower KP or raise KD. If it's sluggish → raise KP. Most tracks only need KP + KD.

Speed

Constant	Default	Notes
SPEED_BASE	150	Normal tracking speed
SPEED_MAX	200	Upper speed limit
SPEED_TURN	120	Line‑search speed
SPEED_SLOW	80	Precision turns

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📁 Repository Structure

robot_line_follower/
├── ard/
│   ├── Gambar_Lintasan.png        # Track illustration
│   └── code/
│       ├── line_follower.ino      # Main Arduino sketch
│       └── spesifikasi.txt        # Detailed hardware spec
├── LICENSE                        # MIT License
├── .gitignore
└── README.md

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🛠️ Common Issues

Symptom	Likely Fix
Robot doesn't follow line	Re‑calibrate: ensure sensors see black & white during startup
Oscillates wildly	Lower KP or raise KD
Loses line on sharp turns	Raise SPEED_SLOW, check sensor alignment
Motors don't move	Verify L298N power (5‑12V input), check ENA/ENB jumpers
Erratic sensor readings	Reduce ambient IR light; add heat‑shrink to sensor housings

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📄 License

MIT — see LICENSE for details.