This talk delves into the technical aspects of the Tanmatsu hardware design, the latest creation by the badge team, set to be released alongside the availability of ESP32-P4 chips. It will also form the foundation for the WHY2025 badge. Topics include an exploration of the PCB's high-level design, cost considerations for producing 4000 units, challenges and insights from working with pre-release chip prototypes, and a discussion on the practical aspects of MIPI DSI/SCI interfaces, including LVDS and impedance. The session will share both the hurdles and triumphs encountered during the design process.