Often I wear my headphones at work and listen to music. Unfortunately I sit at a corner desk and my view of the office entrance is obstructed. This leads to people standing over my shoulder with out my knowing about it. This bugs me, so one day I decided to do something about it.
Goals
While I could very well have placed a mirror on my desk or monitor I decided that it would be nice when someone walks in to receive some form of notification in the form of a balloon notification, audible tone, or a screen flash. This requires a motion sensor that can interface with my PC.
Requirements
- Inexpensive
- Simple to build
- Small
- Reliable (Not to many false positives)
Design
After doing some research I decided a PIR (Passive Infrared) sensor would be sufficient. I found this one [(Parallax PIR Rev.B)] which is widely available at your local Radio Shack.