This document is a mini project report submitted by three students (Rahul Vaity, Sumedh Vartak, and Rohit Vasta) for their course on mini projects. It outlines their project to build a mobile phone detector circuit. The circuit uses an antenna to detect radio frequency signals from nearby mobile phones and triggers an alarm with a blinking LED. The report includes the circuit diagram, descriptions of the components used, and the basic working principle of how it detects mobile phones. It was submitted under the guidance of their professor Shripad Kulkarni.