Project Overview
Team Tango designed and built an autonomous micromouse robot for Notre Dame Electrical Engineering Senior Design. The project was inspired by the traditional Micromouse challenge, where a small robot must explore a maze, identify walls, plan a path, and complete the maze without human control.
Our robot combines custom hardware, embedded software, sensing, motor control, and system testing into one integrated platform. The final mouse uses IR wall sensors, motor encoders, an IMU, two rear-mounted DC motors, and a custom four-layer PCB built around an ESP32-S3 microcontroller.
The project gave our team experience with circuit design, PCB layout, sensor calibration, software architecture, debugging, and the process of turning an engineering concept into a working autonomous robot.
Team Members
-
Benjamin Walsh
Hometown: Hinsdale, Illinois
Email: bwalsh7@nd.edu -
Annie Marquitz
Hometown: St. Louis, Missouri
Email: amarquit@nd.edu -
Daniel Harrison
Hometown: Louisville, Kentucky
Email: dharri23@nd.edu -
Edgar Rodriguez
Hometown: San Antonio, Texas
Email: erodri27@nd.edu
System Requirements
The main goal was to create a compact robot that could move through a maze reliably. The mouse needed to drive straight, complete accurate 90° and 180° turns, detect walls on the front and sides, and use feedback from encoders, IR sensors, and the IMU to correct its position.
- Fit within maze corridors and turn without clipping the walls.
- Detect a front wall at about 35 mm so the robot can stop and align.
- Detect side walls at about 50 mm to help stay centered in a corridor.
- Update sensor readings fast enough for a 20 ms control loop.
- Coordinate both motors independently using PWM and encoder feedback.
Hardware Design
The hardware system is centered on a custom four-layer PCB. A two-layer board would have been simpler, but it would have made routing difficult because the board needed to connect the microcontroller, motor driver, IMU, sensors, USB-C port, switches, LEDs, and supporting circuitry in a compact layout. The four-layer design gave the team more room to route signals and reduce congestion.
- Controller: ESP32-S3-WROOM-1 microcontroller.
- Power: two 3.7 V LiPo batteries in series for the motors and 3.3 V regulation for board electronics.
- Motor driver: DRV8411 dual H-bridge motor driver for the two rear-mounted DC motors.
- Sensing: IR LEDs and phototransistors with op amp signal conditioning.
- Motion feedback: motor encoders and an LSM6DSV IMU for heading correction.
- Mechanical additions: custom battery holder and 3D-printed IR sensor shrouds.
Software Design
The robot software was written in C++ using VS Code. The software handles sensor readings, motor commands, encoder tracking, IMU correction, maze mapping, and path planning. The control system uses PID-style correction to adjust motor PWM while the robot drives through maze cells.
- Uses IR wall readings for one-wall and two-wall correction.
- Uses IMU heading correction when no wall is available for sensor-based centering.
- Uses encoder feedback to estimate travel distance and support turning.
- Uses verified turns when needed and faster turns in known safe cells.
- Uses flood-fill maze solving to explore the maze and identify a faster path.
System Testing
Testing began with a practice mouse and then moved to the team’s custom board. The team tested different motor speeds, compared ToF sensors with analog IR sensors, tuned PWM and PID values, calibrated wall sensors, and adjusted movement behavior through repeated maze tests.
- 500 RPM motors were selected as a balance between speed and controllability.
- Analog IR sensors were selected because they provided fast short-range wall detection.
- Control testing focused on straight driving, turns, wall following, and speed increases.
- The final mouse successfully solved the maze in 1 minute and 38 seconds.
Project Documents
The links below provide access to Team Tango's final report and related project files.
Note: Software files may be submitted separately through Canvas if they should not be posted on the public website.