Observer

The Observer is a Redstone component that detects block updates and emits a short Redstone pulse when a change occurs. It is commonly used in farms, Redstone circuits, and automated contraptions. An Observer is crafted using 6 Cobblestone, 2 Redstone Dust, and 1 Nether Quartz in a 3×3 crafting grid. It does not generate naturally and must be crafted by the player.

The Observer has two sides: a detection face and an output face. The detection face, which looks like a sensor, checks for changes in the block directly in front of it. When a block is placed, removed, or changes state, the Observer sends a 1-tick Redstone pulse from its output face.

An Observer can be placed facing any direction, making it useful for detecting crop growth, piston movements, liquid flow, and other block updates. It does not detect entity movement but reacts to certain block updates, including doors opening, crops growing, and Redstone power changes. An Observer can be mined with any tool, but pickaxes break it the fastest. Unlike a Redstone Repeater, it does not extend signals but is essential for detecting block changes in Redstone builds.