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Pulse circuit

Falling-edge detector

Trigger an action when an input finishes.

6 × 3 footprint1 layer11 blocksTested in 4 rotationsJava Edition 26.2
Open in the simulatorBuild it in the game

Layout

Layer 0 (on the floor)
lever [face=floor, facing=north, powered=false] at x 0, z 0redstone dust at x 1, z 0repeater [facing=west, delay=4] at x 2, z 0comparator [facing=west, mode=subtract] at x 3, z 0redstone dust at x 4, z 0redstone lamp at x 5, z 0redstone dust at x 1, z 1redstone dust at x 1, z 2repeater [facing=west, delay=1] at x 2, z 2redstone dust at x 3, z 2repeater [facing=south, delay=1] at x 3, z 1
redstone dustrepeater or comparatorinputlamparrows point where a device sends its output; north is up

How it works

The comparator subtracts two differently delayed copies of the input. A falling edge makes a 4-game-tick raw output pulse; holding the input produces no further pulses. Wait 20 game ticks between input changes. The lamp remains visible four game ticks after the wire turns off.

  1. A subtract comparator receives differently delayed copies of the input.
  2. On release, its side input falls before its main input, producing a four-game-tick raw output pulse.

Timing

Measured at the output: a pulse of 0 game ticks (0.00 s) per event.

Inputs and outputs

  • Inputlever (x 0, y 0, z 0)
  • Outputraw pulse (x 4, y 0, z 0)
  • Indicatordicator: lamp (x 5, y 0, z 0)

Blocks you need

5 × redstone dust, 3 × repeater, 1 × lever, 1 × comparator, 1 × redstone lamp.

Build it in the game: 11 commands

Relative to where you stand, with x running east and z running south. Paste one line at a time into chat, or into a chain of command blocks. The block art is the game's own; the layout is what the page above shows.

setblock ~0 ~0 ~0 minecraft:lever[face=floor,facing=north,powered=false]
setblock ~1 ~0 ~0 minecraft:redstone_wire
setblock ~2 ~0 ~0 minecraft:repeater[facing=west,delay=4]
setblock ~3 ~0 ~0 minecraft:comparator[facing=west,mode=subtract]
setblock ~4 ~0 ~0 minecraft:redstone_wire
setblock ~5 ~0 ~0 minecraft:redstone_lamp
setblock ~1 ~0 ~1 minecraft:redstone_wire
setblock ~1 ~0 ~2 minecraft:redstone_wire
setblock ~2 ~0 ~2 minecraft:repeater[facing=west,delay=1]
setblock ~3 ~0 ~2 minecraft:redstone_wire
setblock ~3 ~0 ~1 minecraft:repeater[facing=south,delay=1]