During the research and development phase of co-founding Berta Medical, I designed a modular development board for a wearable ECG system. This design facilitates easy access and modularity, enabling ongoing firmware development and iterative improvements to the system's functionality. The board incorporates an ESP32 C3 Devkit microcontroller for its WiFi 6 capabilities and processing speed, alongside a 128x32 OLED display for quick debugging. It features a micro SD card module for local ECG data storage and a SparkFun AD8232 ECG module for obtaining ECG readings. To power the system, I selected an 18650 battery for its efficiency, compactness, and reliability, paired with a TP4056 USB-C charging circuit. The enclosure is 3D printed, with a laser-cut acrylic top that allows visibility of the components and indicator LEDs, as well as OLED readouts, showcasing the system's functionality in real time.