Smart mirrors are displays that are built into mirrors and can show information like news, weather, calendars and more. They detect when a person is in front of the mirror and display a user interface. This document describes how to build a smart mirror using components like a two-way mirror, monitor, Raspberry Pi, sensors and speakers for around $392. It also discusses marketing the mirror by highlighting its ability to be customized, take selfies, and be controlled through gestures and voice commands.