Projects | Aviel Fernando

Overview

Quest is a fully autonomous two-wheeled explorer robot standing 70cm tall. Inspired by Wall-E's aesthetic and movement, it combines mechanical engineering with advanced electronics and real-time control systems. The robot features a servo-controlled head that responds to RFID tags and environmental inputs, making it interactive and engaging in social spaces.

Every component was hand-selected for reliability and performance. The design prioritizes modularity, allowing for easy hardware upgrades and feature additions without major structural changes.

Technical Specifications

Microcontrollers

Arduino Mega 2560 – motor control, sensor I/O
Raspberry Pi 4 – vision processing, high-level logic
Serial communication @ 115200 baud

Drive System

2× DC motors (wheel drive)
L298N motor driver (5-35V, 25A)
Differential kinematics for precise steering
Rubber-treaded wheels for traction

Head & Actuators

2 - 15kg servo motors (pan/tilt head)
1 - 9g servo (antenna movement)
PCA9685 PWM driver (16-channel)
Smooth coordinated motion sequences
Laser beam for accurate - facial recognition

Sensors & I/O

MFRC522 - arduino RFID reader (13.56MHz)
Passive buzzer (sound triggers)
Optional: ultrasonic distance sensors
Party Protocol tag detection system

Power

7.4V Li-ion battery pack (2S 2500mAh)
Power distribution board with buck converter
5V logic rail, 12V servo rail
Estimated 4-6hr runtime

Dimensions

Height: 70cm (wheel to top of head)
Wheelbase: 25cm
Width: 30cm (motors + chassis)
Weight: ~4kg (with battery)

Design & Build Process

August 2026

RFID & Sound Integration

Successfully integrated MFRC522 RFID reader. Implemented Party Protocol tag detection with buzzer sound triggers. Tested multiple tag types and response sequences for engaging social interactions.

July 2026

Electronics Finalized

Component selection complete: Arduino Mega, Raspberry Pi 4, L298N motor driver, PCA9685, 15kg servos, 9g antenna servo. Designed power distribution board with buck converter for dual voltage rails (5V logic, 12V servos).

June 2026

Mechanical CAD & 3D Printing

Created full CAD models in Fusion 360. Designed chassis, head mount, wheel hubs, servo brackets. Started 3D printing core structural components. Iterative testing to ensure servo movement clearance.

May 2026

Concept & Research

Initiated Quest as a Wall-E-inspired autonomous robot. Researched differential drive kinematics, servo control systems, RFID technology. Scoped feature set and power budget for autonomous operation.

Key Features

RFID-Triggered - Modes

Responds to specific RFID tags with coordinated head movements, sounds, and light animations. Perfect for social robotics and interactive displays.

Autonomous Head Control

Pan and tilt servos enable dynamic head movements. Programmed sequences for looking around, reacting to stimuli, and engaging with people.

Real-time Motor Control

Precise motor control via PWM. Differential drive allows for smooth curves, tight turns, and accurate positioning without encoders.

Multi-layer Communication

Arduino handles low-level motor/sensor control. Raspberry Pi manages vision and high-level logic. Seamless serial communication between boards.

Efficient Power Management

Single Li-ion battery powers everything through an optimized PDB. Voltage regulation ensures stable operation across all components.

Modular Design

Servo mounts are standardized. Power and signal connectors are accessible. Easy to upgrade motors, add sensors, or modify the head.

Wiring Overview

Arduino Mega Pinout

Motor Control: Pins 5-8 (PWM) + 9-12 (direction)
RFID CS: Pin 48, SCK: 52, MOSI: 51, MISO: 50
Buzzer: Pin 13 (PWM)
PCA9685 I2C: SDA (Pin 20), SCL (Pin 21)
Raspberry Pi Serial: TX1 (Pin 18), RX1 (Pin 19)

Power Distribution

Battery → Main PDB: 7.4V in
PDB → Arduino Mega: 5V (via buck converter)
PDB → Servo Rail: Direct 7.4V (with capacitor bank)
PDB → Motors: Direct 7.4V via L298N

Quest