- Project Overview
- Project Status
- Hardware Architecture & Features
- Component Integration (BOM)
- Wiring Schematic (Pinout)
- Competition Setup (Pit Lane)
- System Architecture & Control Flow
- Credits & Team
- License
The LineFollower-General-Lee-Version-2 repository serves as a technical showcase and documentation portfolio for the hardware architecture of a high-speed line-following robot (velocista) developed by the RoboTec robotics club.
This project demonstrates the engineering behind a competition-grade robot, featuring a custom 16-sensor reflective array ("Hermes") and an advanced Proportional-Integral-Derivative (PID) control system. The design includes dynamic real-time tuning, high-inertia predictive braking, and multiplexed analog processing.
Note: This repository is dedicated to the hardware documentation and architectural overview. The core C++ control firmware remains proprietary and is maintained in a private repository by the RoboTec engineering team.
Competition Ready / Stable - The hardware architecture and integration described here represent the final, track-tested iteration of the robot.
The robot's hardware is engineered for extreme speed, precision, and adaptability on the track. The core control logic features dynamic PID profiles, differential predictive braking for 90-degree curves, and software optical inversion.
Below is the detailed breakdown of the physical modules driving the robot:
The fully assembled chassis houses the high-speed powertrain driven by two 3000 RPM DC motors. These are controlled by a TB6612FNG motor driver capable of handling 1.2A continuous current (3A peak). This powertrain executes the rapid acceleration and the aggressive reverse "anchor" maneuvers required for predictive braking.
The "Hermes" board is a custom frontal array of 16 analog reflective sensors designed for high-resolution line tracking. It utilizes a CD74HC4067 multiplexer to rapidly cycle through 16 channels, bypassing the Arduino Nano's pin limitations and outputting a precise analog reading for center-weighted average calculations.
To comply with official race standards, the robot interfaces with an Ingeniero Maker RF receiver. This module provides critical logic signals:
- Ready Signal: Activates "Sentinel Mode", an active low-speed self-centering routine ensuring perfect starting alignment.
- Go Signal: Officially unlocks the high-speed main PID control loop, launching the robot.
| Component | Specifications | System Role |
|---|---|---|
| Microcontroller | Arduino Nano (ATmega328P) | Core processing and PID control loop execution. |
| Sensor Array | Custom "Hermes" Board | Frontal 16-sensor array for high-resolution line tracking. |
| Multiplexer | CD74HC4067 | 16-channel analog multiplexing. |
| Motor Driver | TB6612FNG | PWM power control. |
| Powerplant | 2x DC Motors (3000 RPM) | Differential traction and high-speed propulsion. |
| Power Supply | LiPo 2S (7.4V nominal) | Main power source for motors and logic. |
| Start Module | Ingeniero Maker RF Module | RF receiver providing official Ready/Go logic signals. |
The internal integration follows this exact logic distribution:
Motors & TB6612FNG Driver
AIN1: D8 |AIN2: D7 |PWMA: D5 (Right Motor)BIN1: D9 |BIN2: D4 |PWMB: D6 (Left Motor)
"Hermes" Sensor Array (CD74HC4067)
S0: A3 |S1: A2 |S2: A1 |S3: A0COM(MUX Analog Output): A4
Start Module (Ingeniero Maker)
RDY(Ready Signal): D12GO(Start Signal): D10
To operate the robot under competition conditions, the following workflow is executed in the pit lane:
- Power Initialization: Power on the robot using the 2S LiPo battery. The system defaults to the first stored PID profile.
- Profile Selection: If the
GOsignal has not been received, the user can press the onboard button (or use theReadyinput) to cycle through the stored PID profiles. An onboard LED indicates the currently selected profile. - Sentinel Alignment: Upon receiving the
Readysignal via RF, the robot enters Sentinel Mode. It actively aligns itself with the track line at a very low speed to ensure perfect starting position. - Race Launch: Upon receiving the
GOsignal, the main high-speed PID control loop is unlocked, and the race sequence begins.
While the codebase is private, the internal control flow operates as follows:
- Data Acquisition: The Arduino rapidly iterates through the 4 control pins (S0-S3) of the CD74HC4067 multiplexer, reading the single analog output (
COM) to scan all 16 sensors on the Hermes board. - Error Calculation: A center-weighted average algorithm processes the analog values to calculate the exact positional error relative to the track line.
- PID Processing: The selected PID profile calculates the necessary correction. If a 90-degree curve is detected, the predictive braking algorithm interrupts standard PID output.
- Actuation: The calculated response is converted into independent PWM signals sent to the TB6612FNG driver, generating differential thrust in the 3000 RPM motors.
This hardware architecture and its underlying control logic are the result of dedicated engineering and testing.
- Mauricio Gómez Márquez - Software Architecture, PID Control Logic, and Firmware Optimization.
- Alexander Armando Martinez Gil - Hardware Engineering, PCB Design ("Hermes" Board), and Sensor Integration.
- RoboTec Robotics Club - Organization, testing facilities, and community support.
The hardware architecture documentation, pinouts, and visual presentations in this repository are released under the MIT License. See the LICENSE file for details.
Note: The underlying C++ control firmware remains proprietary to the organization and is not covered by this open-source license.