The engineering problem
One-month hardware internship at Photon Smart: take a commercial WiFi water-leakage sensor with no available schematic, document it, and redesign it for production.
The reference device worked, but there was no schematic to build on — only the board itself. Any revision had to start by recovering the design.
Approach & contribution
Reverse-engineered the commercial device and documented its architecture: STM32 microcontroller, ESP wireless module, boost converters, and peripheral circuitry.
Redrew the design from scratch as a hierarchical KiCad 8 schematic: Power, MCU, WaterSense, Indicator, WiFi, and Memory sheets.
Improved the design with reverse-polarity protection, a more efficient microcontroller and wireless module, and better power management.
Laid out a production-ready PCB, built on Photon Smart's shared KiCad component library.
Results & boundaries
A complete, documented hierarchical schematic where there had been none.
A production-ready PCB layout delivered at the end of the internship.
Internship completion certificate from Photon Smart.
Content basis: MAZEN_CONTEXT v1.3, 9 October 2026