A block that detects other blocks. Functions are similar to the note block.

This is a directional block that pays attention to whatever block is placed in front of it and outputs a signal behind it. The new block does not output a signal for block updates so for example it would ignore a piston moving.

When any block is placed in front of it, the detector block gives a constant redstone signal. It outputs different redstone signal strength based on the block it detects so you can use a comparator tell which block is placed in front of it.

When this new block detects something this also count as a block update so you can use an observers with this new block.