A broken CD or DVD or other type of optical disc is a serious problem and one that will likely lead to loss of information stored on this media. A broken optical disc refers to a disc that has split into two or more pieces or perhaps a disc simply missing one piece.
A motion detector is a device that detects moving objects, particularly people. A motion detector is often integrated as a component of a system that automatically performs a task or alerts a user of motion in an area.
Particle detector. In experimental and applied particle physics, nuclear physics, and nuclear engineering, a particle detector, also known as a radiation detector, is a device used to detect, track, and/or identify ionising particles, such as those produced by nuclear decay, cosmic radiation, or reactions in a particle accelerator.