• Programmed ESP32-WROOM in C using Arduino IDE; integrated MAX30102 (pulse + SpO₂), VL53L1X (height via ToF), and HX711 ADC with 4 load cells over I2C
• Designed two-layer PCB in KiCad including test lines for inter-device communication debugging
• Device sends JSON data over Wi-Fi via router; built Android companion app in Kotlin (MVVM, Retrofit)
• Full-stack ownership: hardware, firmware, PCB, mobile app