ObsidiPlates

Overview
ObsidiPlates is a mod, by Myrathi, providing pressure plates that can only be activated by either players or NPCs, depending on what they're made of.

Originally created as a surprise for Jadedcat, it implements (using original code) a concept she missed from Better Than Wolves (which is why the primary plates uses obsidian, specifically).

Minecraft 1.4.6/1.4.7
In this version of ObsidiPlates, only the Obsidian Pressure Plate is available.

Minecraft 1.5.1
As of v1.3.2 build 11, Myrathi added five (5) more plates:


 * Mossy Pressure Plates: made with mossy cobblestone, instead of obsidian, can only be activated by NPCs.
 * Silent versions: made by crafting an Obsidian or Mossy Pressure Plate over a block of wool, disables the clicking sound.
 * Shrouded versions: made from Noisy or Silent, Obsidian or Mossy Pressure Plates, by alternating nether quartz and glowstone dust around the plate in the crafting grid, makes them almost entirely transparent.

Minecraft 1.5.2
As of v1.5.0 build 13, Silent and Shrouded Plates can be smelted, in a furnace, to remove the extra properties, returning a basic Obsidian or Mossy Pressure Plate.

How It Works
All plates are a type of switch that can be placed onto the surface of a block. If connected, by wire, to an object (or placed adjacent to a block that can be powered), it will provide power to that object or block when stepped on by a player (or NPC, if a Mossy Pressure Plate) and will stop when stepped off.

As opposed to wooden and stone pressure plates, Obsidian Pressure Plates will not respond to items or NPCs and Mossy Cobblestone Plates will not respond to items or players.

Silent versions of these plates make no sound.

Shrouded versions of these plates are see-through.

Silent and Shrouded plates can only be be crafted as silent first then adding shrouded last.