Objective: To replace expensive camera tracking systems (e.g., Hawk-Eye) by automatically detecting whether a ball is “in” or “out” on a tennis or badminton court in ambiguous situations near the lines. Principle: Two infrared transmitters are deployed on either side of the court boundary line. Each laser module is symmetrical with a transmitter and a receiver. If a ball crosses the beam: if it crosses the beam outside the line, the system detects “Out”; if it crosses the beam inside the line, the system detects “In.” I think I will optimize the whole thing with, most likely, lenses on the IR LED and a tube that reduces interference from ambient light. The other components are: an ESP32 S3 Supermini, and then I can potentially add a 0.96" OLED screen, a solar panel to be energy self-sufficient coupled with a battery, and add a score management and display system with perhaps a centralized interface such as a television connected to all my small modules. I can also add connectivity thanks to the integrated Bluetooth and Wi-Fi on the ESP32 S3 and a small visible laser to align the modules with each other.