UTRA Hacks 2026 Autonomous Robot

Arduino Uno + PlatformIO project for an autonomous robot that navigates the Winter-Olympics style course, drops boxes, follows paths, aligns to target center via color, shoots the ball, and returns.

Overview

• Motors: 2x DC with L298N driver
• Servos: claw (pick/drop), shooter (launch)
• Sensors: 2x IR line sensors, HC-SR04 ultrasonic, TCS3200 color sensor
• Control: modular drivers and a simple state machine in src/main.cpp

Pin Assignments (see include/pins.hpp)

• Motor (L298N):
  • ENA 5, IN1 7, IN2 8 (Left)
  • ENB 6, IN3 11, IN4 12 (Right)
• Servos: Claw 9, Shooter 10
• IR sensors: Left A0, Right A1
• Ultrasonic: TRIG A2, ECHO A3
• TCS3200: S0 2, S1 3, S2 4, S3 13, OUT A4
• Cal button (optional): A5 (INPUT_PULLUP)

Build & Upload

cd "/Users/ericx/Documents/PlatformIO/Projects/UTRA Hacks 2026"
platformio run
platformio run -t upload

• Open Serial Monitor at 115200 baud.

Serial Commands

• h: show help
• ir: print IR analog values (Left/Right)
• d: print ultrasonic distance (cm)
• m f / m s / m l: motors forward/stop/slow
• c o / c c: claw open/close
• shoot: fire shooter
• rgb: raw TCS3200 pulses (lower = brighter)
• rgbn: normalized 0..255 RGB and classification
• Tunables at runtime:
  • set bs <int>: base speed
  • set tg <int>: turn gain
  • set ib <int>: IR black level
  • set iw <int>: IR white level
  • set rmin|rmax|gmin|gmax|bmin|bmax <int>: color calibration ranges

Color Calibration (TCS3200)

This project aligns to the calibration scheme using pulse widths:

• Raw pulses: rgb prints R, G, B pulse widths (lower = brighter)
• Normalized values: rgbn maps pulse ranges to 0..255 (255 = bright) via Config::R_MIN/R_MAX, G_MIN/G_MAX, B_MIN/B_MAX.
• Update ranges live using set rmin/rmax/... commands.
• Initial ranges set in include/config.hpp:
  • R: 44–72, G: 51–121, B: 67–71

Tuning (see include/config.hpp)

• Speeds: BASE_SPEED, SLOW_SPEED, TURN_GAIN
• IR thresholds: IR_BLACK_LEVEL, IR_WHITE_LEVEL
• Ultrasonic stop distance: OBSTACLE_STOP_CM
• Shooter/claw positions: SHOOT_*, CLAW_*

Behavior Summary

• Search for box (line follow + ultrasonic stop)
• Pick box (claw close) → drive to blue zone → drop box
• Choose green path → detect rings → sweep to black center
• Shoot ball → back off → return along line

File Structure

• platformio.ini: PlatformIO environment
• include/pins.hpp: pin assignments
• include/config.hpp: tunable parameters + color calibration ranges
• src/main.cpp: drivers, state machine, Serial interface
• lib/: optional libraries
• test/: PlatformIO tests (empty by default)

Safety & Notes

• Secure all wiring; avoid shorts and strain on servo cables.
• Verify motor polarity and servo angles before full-speed tests.
• Ramp approach: prefer SLOW_SPEED for alignment; increase only after stable.