This post explains the technical background of the security camera system, shown in the following movie. The post will answer the questions: How to detect a thief, how to take a photo, how to get notifications on your phone, and whether the system would work in reality.
In order to detect a thief I made use of an acceleration sensor that I placed at the apartment’s door. The sensor listens for significant changes in the measured x-acceleration. This technique was so precise, that even the slightest knock triggered the motion detection.