Pressure Plates

Pressure Plates are used to activate traps with wire). The plates sit partially hidden on top of blocks. it can be purchased from a Mechanic or taken from a cave underground. It first appeared in worlds that were made after the 1.1 patch. It activates when the player steps on it. They also allow you to see wire when held.

Pressure Plate is a great tool for opening and closing doors without having to click on them.