Hardware & PCBs

Most FPV races are held after dark, and it is often mandatory to have LEDs on all four arms. These LEDs typically utilize the WS2812B protocol. Currently, most off the shelf solutions use a separate board to connect the LEDs, featuring a physical button to cycle through colors and patterns. Since none of these are in stock across India at the moment, I decided to design my own. I chose the ATtiny202 as my microcontroller and paired it with a TI TPS62933 buck converter to handle input voltages from 3S to 6S batteries. Initially, I designed the PCB to fit a traditional 20mm x 20mm drone racing stack, but I no longer think that is the most optimal layout. Modern racing frames compress the stack height as much as possible; adding an extra board simply isn't feasible or ideal. I plan to revisit the design once I discover a better mounting solution. That is the primary reason I haven't sent it to fabrication yet. Designing this taught me how simple most consumer electronics truly are. I was able to select components that kept the manufacturing cost for 10 units below the retail price of commercial alternatives, such as those from HGLRC. Plus, I achieved this using a much more versatile MCU like the ATtiny, rather than a generic industrial MCU with the part numbers laser-etched off.

During the 2025 WRO Future Engineers competition, we were disqualified because the data on our Raspberry Pi became corrupted and the SD card failed. Months later, I analyzed the output voltage of the 5V, 5A-rated buck converter we had been using. I discovered that the Raspberry Pi was constantly undervolting under load. We had attempted to add a capacitor before the competition to resolve the issue, but the effort proved futile. Upon reviewing the logs, I confirmed that these undervoltage events were, in fact, what caused the SD card to fail. I searched the market for a buck converter capable of providing the 5.1V required by the Raspberry Pi to prevent undervolting, but I couldn't find a suitable option. Consequently, I decided to design my own. Using the TI LM61460, I designed a buck converter in KiCAD that accepts a 3S-6S battery input and outputs a steady 5.1V at 5A continuous. Due to the small physical size of the IC, I had to incorporate extensive thermal management into the PCB layout. I had the PCB fabricated and assembled by JLCPCB, and I am very happy with the results. I stress-tested the converter at 5A for eight hours, and it performed flawlessly without any issues

engineered and fabricated a bespoke CoreXY 3D printer, all from scratch, by synthesizing Voron influenced kinematics with a custom Z-axis assembly. This triple lead screw bed system, inspired by the Bambu Lab X1C, utilizes a single motor to maintain synchronization across the build plate. The machine is powered by a BigTreeTech SKR Mini E3 V3 and a Raspberry Pi 4 running Klipper firmware. While the printer reliably sustains speeds of 500mm/s, the current performance ceiling is dictated by the hotend's maximum volumetric flow rate rather than mechanical instability. This project served as a deep dive into systems integration and the principles of kinematic constraint. I successfully optimized the design by eliminating parasitic degrees of freedom and managing tolerance stackup, ensuring all components are properly constrained to prevent unwanted deflection during high acceleration moves.