Darren Liu


Electrical Engineering · University of Waterloo

RTOS

Raspberry Pi RTOS

Bare-metal real-time OS for the CM4 - preemptive scheduler and IRQ context switching in C and ARM assembly

Bootloader

Raspberry Pi Bootloader

Bare-metal bootloader for the CM4 - UART firmware updates (DFU) and eMMC image loading

RISC-V CPU

5-Stage Pipelined RISC-V CPU

Full RV32I pipeline with forwarding, stalling, and branch flushing in Verilog

PCB Project

My PCB Projects

Seven custom boards - flight controllers, sensor interfaces, and motor drivers

CM4 Board

Custom Hardware + Firmware Interface for RPi 4

Full hardware + software stack for a Raspberry Pi 4 robotics application

Drone V2

Mini Drone V2

Second iteration of my custom quadcopter - redesigned PCB, tighter firmware, improved stability

Swerve Drivetrain

Differential Swerve Drivetrain

Fully functional swerve drive with independent wheel steering and drive control

Mini Drone

Custom Mini Drone

Scratch-built quadcopter with custom PCB, firmware, and 3D-printed frame

FRC 2024

FIRST Robotics Competition 2024

Hardware and software contributions to the 2024 FRC season

Drive Module

Differential Swerve Drive Module

Prototype wheel module rotating on two axes with PID-controlled motor pair

FRC 2023

FIRST Robotics Competition 2023

Hardware and software contributions to the 2023 FRC season

Smart Bin

Smart Trash Bin

Autonomous waste sorter using OpenCV classification and sensor-triggered actuation