Mechanisms: turning power into action

Wiring and logic decide *when* a signal arrives; mechanisms decide *what happens* when it does. These are the output devices at the end of a circuit — they take power from any adjacent redstone source and perform an action. Some react the instant they are powered, others fire only on a rising edge (the moment power switches from off to on), so it pays to know which is which. Here is the whole group, organized by what they do.

Lights and indicators

These light up to show a signal — useful as circuit readouts or for triggering observers.

• Redstone Lamp — lights instantly when powered from any direction (strong or weak, level ≥1), then turns off after a 2-tick delay once unpowered. A lamp keeps its lit state when a piston pushes it, so a pushed lamp keeps glowing for its remaining off-delay.
• Copper Bulb — a built-in T flip-flop: each rising power edge *toggles* it on or off, and it holds that state until the next pulse. A comparator reads 15 off a lit bulb no matter how oxidized it is.
• Note Block — conductive like a solid block: once it is powered, it powers adjacent redstone dust at that level and activates the mechanisms around it. There is no sound or note pitch in this engine, and a comparator behind one reads it as an ordinary block, not a pitch.

Barriers

All three open while powered and close when unpowered — power level ≥1 from any direction is enough. In this engine their open/closed state is render-only and read-only; it has no game effect, so pistons and blocks pass straight through.

• Door — opens while powered, closes when power drops.
• Trapdoor — opens and closes instantly with no delay, unlike the lamp's delayed off.
• Fence Gate — behaves identically to the door and trapdoor in the power domain.

Demolition

• TNT — primes on a rising power edge, counts down 8 ticks, then detonates and clears every block within a 1-block radius (Chebyshev). Any TNT caught in the blast is re-lit with a 2-tick fuse instead of being destroyed, which is what chains explosions together.

Block movers

Pistons turn a signal into motion. Both face all 6 directions and push up to 12 connected blocks one cell forward — exceed that limit and the piston refuses to extend at all.

• Piston — extends when powered (directly, or by quasi-connectivity from the block above) and pushes the line forward; on retract it leaves the pushed blocks stranded. It destroys fragile parts (dust, levers, torches) in its path.
• Sticky Piston — pushes like a normal piston, and on retract pulls the single block in front of its head back one space. It pulls only that one block; if it is immovable (a piston, comparator, or container), the pull fails silently.

Item handlers

These move items rather than blocks. The first three eject on a rising power edge and face all 6 directions; the hopper runs on its own clock and is controlled by power instead.

• Dispenser — ejects one item into the world on a rising edge. It always ejects to the void, never into a container — only droppers and crafters can feed containers.
• Dropper — ejects one item on a rising edge. If a container sits in the block it faces, the item moves into it (kept if the container is full); otherwise it ejects into the world.
• Crafter — ejects one item on a rising edge, just like a dropper — into a facing container or else the world. A comparator reads its fullness (0–15) from the rear.
• Hopper — pushes one item into the container it faces and pulls one from the container above, both on a 4-tick cooldown. Power it from any adjacent source to lock it and freeze all transfers mid-stream.