Sesame: Lock Your Mac Wirelessly

Keeping your computer unlocked when you go away is not smart. Unfortunately, many of us forget to lock our computers. Sesame can help. This wireless gizmo locks your computer automatically when you are far enough. When you come back, the Mac Sesame app will sense the key and unlocks your screen. All you have to do is carry the key in your pocket. You can auto-mute and auto-pause iTunes while leaving your Mac.

This is a Bluetooth 4.0 device, so it will run for a while. The device sets you back $39.99.