This document describes an exhaust fan with a PIR sensor that is designed to minimize energy usage by automatically turning the fan on when motion is detected. It provides details on the tools and materials used, which include an Arduino Uno, fan, LED, PIR sensor, resistor, acrylic, and jumper wires. The wiring circuit and coding are explained, with the fan turning on when motion is detected by the PIR sensor and turning off when no motion is present.