Contract software engineer, Apex Instruments
Mar 2026 – presentXD-502 emissions-testing console (shipped)
- Sole developer of the ESP32 firmware and built-in Wi-Fi web app for an EPA stack-emissions testing console, letting technicians monitor, control, calibrate and download tests from any phone or laptop.
- Added over-the-air firmware updates, seven-language support and a two-tier password lock for calibration values.
- Serialized commands from several simultaneous web users through one mutex-protected FreeRTOS queue.
- Traced a Wi-Fi fallback fault to two root causes across the ESP32 and PIC32 boards and fixed both; made CSV export to SD card and USB drive reliable in the PIC32 firmware.
Next-generation automated sampling console (in development)
- Leading a ground-up rewrite covering firmware for three boards (PIC32MZ, ESP32), a browser app and a Python hardware simulator: about 41,000 lines of C, warning-free under -Werror -Wconversion with no dynamic allocation.
- Implemented EPA Method 1–5 isokinetic calculations in C, mirrored in Python and JavaScript with parity tests against the previous-generation console.