🏎️ 8-Channel Fast Line Follower Robot

A high-speed, competition-ready line follower built with an Arduino Nano, N20 motors, and an 8-channel TCRT5000 sensor array multiplexed for fast map pattern recognition.

(Built and programmed to compete in fast line-follower robotics competitions, capable of handling complex track patterns, sharp turns, and intersections).

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📂 Repository Structure

Fast-Line-Follower-Nano-8CH/
│
├── 💻 Firmware/               # Arduino Source Code
│   └── Fast_Line_Follower.ino # Main control logic and PID loop
│
├── 🔌 Hardware/               # Electronics and Design Files
│   └── schematics/            # Wiring diagrams and pinouts
│
├── 🖼️ Assets/                 # Images of the robot and competition maps
│
└── 📄 README.md               # This documentation file

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🛒 Bill of Materials (Hardware)

To replicate this competition build, you will need:

• Arduino Nano (The main brain, compact and lightweight)
• 8-Channel TCRT5000 Sensor Array (Infrared sensors for high-resolution line detection)
• Multiplexer (MUX) (Used to efficiently read the 8 sensors without exhausting the Nano's pins)
• 2x N20 Micro Gear Motors (High RPM, low weight for maximum speed)
• MP1485 Buck Converter (Highly efficient step-down converter to provide stable 5V logic power from a LiPo battery)
• Motor Driver (e.g., TB6612FNG or MX1508 for driving the N20 motors)
• 2S LiPo Battery (7.4V for high discharge rate)

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🧠 System Architecture & Wiring

Power Management (MP1485)

In high-speed robots, voltage drops from sudden motor acceleration can reset the microcontroller. The MP1485 Buck Converter steps down the 7.4V LiPo battery to a rock-solid 5V to power the Nano, MUX, and Sensors, while the Motor Driver receives the raw 7.4V directly.

Hardware Schematic Diagram

                                [ 2S LiPo Battery 7.4V ]
                                          |
                   +----------------------+--------------------+
                   |                                           |
            [ Motor Driver ]                          [ MP1485 Buck ]
             |          |                                   | (5V)
        [ N20 Left ] [ N20 Right ]                          |
                                                            v
                                                     [ Arduino Nano ]
                                                            |
                                                   [ Multiplexer (MUX) ]
                                                            |
                                        [ 8-Channel TCRT5000 Sensor Array ]

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💻 Software Logic & Map Pattern Recognition

To achieve high speeds, basic "if/else" left-right logic is not enough. This code is optimized to read all 8 sensors rapidly and recognize complex track patterns commonly found in competitions.

1. The 8-Channel Advantage

With 8 sensors, the robot has a wide field of view:

• Inner Sensors (S3, S4, S5, S6): Used for precise PD (Proportional-Derivative) line centering.
• Outer Sensors (S1, S2, S7, S8): Used exclusively for detecting extreme track features.

2. Map Pattern Handling

The code includes dedicated logic blocks to handle every track anomaly without losing speed:

Track Feature	Sensor Trigger Pattern	Robot Action
Straight Line	0 0 0 1 1 0 0 0	Maximum Speed, PD active.
Slight Curve	0 0 1 1 0 0 0 0	Adjust motor PWM via PD (Proportional steering).
90° Sharp Turn	1 1 1 1 0 0 0 0	Hard brake inner wheel, max power outer wheel.
T-Junction / Cross	1 1 1 1 1 1 1 1	Competition specific: Usually ignore and drive straight, or turn based on pre-programmed maze rules.
Dashed Lines	0 0 0 0 0 0 0 0	Memory state: Continue driving at last known motor speeds until the line reappears.

(0 = White/Background, 1 = Black/Line)

🚀 Getting Started & Tuning

1. Wiring: Connect the Nano, MUX, Motor Driver, and MP1485 according to the schematic. Make sure the MP1485 is tuned to exactly 5.0V BEFORE connecting it to the Nano!
2. Sensor Calibration: TCRT5000 sensors are sensitive to ambient light. Calibrate the thresholds in the code based on the competition floor and lighting conditions.
3. Upload Firmware: Open the .ino file and flash it to the Arduino Nano.
4. PD Tuning (Crucial): (Note: This project uses a PD controller, skipping the Ki term to prevent integral windup at high speeds).
   • Set Kp and Kd to 0.
   • Increase Kp until the robot is able to follow the line but oscillates (wobbles side-to-side).
   • Increase Kd gradually to dampen the wobble and make the robot lock smoothly onto the straight lines and curves.

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🚧 Future Improvements

• Upgrade to a 32-bit microcontroller (like STM32 or ESP32) for faster PD loop calculation times.
• Implement a cooling fan for the motor driver for endurance races.
• Add a start/stop module using an IR remote to comply with strict competition rules.

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🤝 Let's Connect

If you want to discuss line follower algorithms or embedded systems, feel free to reach out!