John F

Robotics Simulation & Autonomy Engineer

AUTIS INGENIEROS • Freelance

Jul 2026 - Aug 2026 • 1 mo

Developed high-fidelity 3D robotics simulation environments and autonomous navigation stacks inside ROS 2 (Humble/Jazzy), Gazebo (Fortress/Harmonic), and Webots. Converted complex mechanical 3D CAD models from SolidWorks and Fusion 360 into fully functional, URDF and Xacro kinematic descriptions with verified inertial matrices, visual collision meshes, continuous joint limits, and transmission tags. Programmed custom ROS 2 Python and C++ nodes for sensor data publishing, wheel odometry calculation, differential drive kinematics, and custom coordinate transform trees (TF2). Configured 2D and 3D SLAM mapping packages (SLAM Toolbox, Cartographer) to process real-time simulated LiDAR point clouds and build high-resolution occupancy grid maps. Integrated the Nav2 autonomous navigation framework, configuring global/local costmaps, inflation layers, DWB local planners, and behavior trees for dynamic obstacle avoidance, waypoint tracking, and autonomous path planning. Created streamlined launch configurations and simulation world environments for rapid robotic testing and algorithm evaluation.

Embedded Systems & Firmware Programmer

RidgeRun • Freelance

Jul 2026 - Aug 2026 • 1 mo

Developed modular, memory-efficient C and C++ firmware for Arduino (Uno, Nano, Mega) and ESP32 microcontroller platforms across automation, robotics, and IoT projects. Programmed low-level communication drivers and hardware abstractions for peripheral communication protocols, including I2C, SPI, UART, and PWM channels. Interfaced diverse hardware components such as IMU sensors (MPU6050), ultrasonic distance transceivers, infrared obstacle arrays, rotary encoders, OLED displays (SSD1306), and motor drivers (L298N, TB6612FNG). Built, verified, and debugged electronic circuit schematics using interactive simulation tools like Wokwi and Tinkercad, generating shareable live simulation links and detailed wiring PDF diagrams for fast hardware validation. Implemented non-blocking event-driven architectures utilizing millis() state machines on Arduino and FreeRTOS task scheduling with queues and semaphores on dual-core ESP32 chips. Handled real-time sensor polling, Wi-Fi telemetry reporting via HTTP/MQTT protocols, and closed-loop PID control loops for precise DC motor speed regulation and servo positioning.

Backend Game Systems & Data Architect

Family Devs • Freelance

Apr 2026 - Aug 2026 • 4 mos

Architected and deployed secure, enterprise-grade backend data persistence frameworks for multiplayer Roblox roleplay and economy games. Implemented bulletproof data-saving pipelines using ProfileService and DataStore2, incorporating automated session locking, retry mechanisms, and transaction journaling to permanently eliminate data rollback bugs, inventory loss, and item duplication exploits during unexpected server crashes. Scripted deep, modular game systems, including multi-account ATM banking loops, dynamic salary distributions, job progression ladders, and property ownership frameworks featuring serializable furniture placement grids with collision checking. Built comprehensive character customization suites supporting layered 3D clothing, accessory attachment sockets, and color palette presets that serialize seamlessly into the player's profile data. Structured authoritative server-side validation layers that check player distance, inventory space, cooldown timers, and currency balances before committing changes to master datastores, establishing exploit-free server stability for concurrent player environments.