Motion sensor

The motion sensor is a block which can be used to form large automatic doors. You place the sensors in a line of 8 blocks, and build a "door frame" on the last 2 blocks on each side, with a height of 3. Then, the inside is filled with the door block - this is whatever block you choose, and when you come close to the door, the door blocks start shifting into the frame, opening the door. When you walk away, the door blocks come back. You can choose any block to be the door and frame. It is best to place the motion sensors in the ground to conceal them.