Photoplate

A photoplate was a photosensitive switch recessed into the wall of the cell corridor of a prison. It was placed between 1 and 1.5 meters from the floor, and when a hand or other object was waved in front of it's surface, an opening was provided in the bars of the designated cell. When activated again, the dematerialized bars would reappear forming a solid barrier once again.

Appearances

 * Splinter of the Mind's Eye