This book won't open if it doesn't like the look of your face

The Cover That Judges You:

My aim was to create a book cover that is human and approachable-hi-tech. If you approach the book, the face recognition system picks up your face and starts scanning it for signs of “judgement”. If you’re over excited or your face shows a skeptical expression, the book will stay locked. But if your expression is neutral (no judgement) the system will send an audio-pulse to the Arduino and the book will unlock itself.

Via.