REDSTONEPEDIA › Circuits › Pulse shapers
One pulse on every switch (dual-edge detector)
2-tick pulse · 2 blocks
Every time the input changes, on or off, the output gives one short pulse of 2 ticks (0.1 s).
made of observer, redstone lamp · fits in 1×1×2
12 versions, 2 to 40 ticks
Every size 12
The best design for each size: pick one to see it.
| size | blocks | numbers |
|---|---|---|
| 2 ticks (0.1 s) (this page) | 2 blocks | starts after 2 ticks (0.1 s) · needs an input of at least 2 ticks (0.1 s) |
| 4 ticks (0.2 s) | 4 blocks | starts after 6 ticks (0.3 s) · needs an input of at least 4 ticks (0.2 s) |
| 6 ticks (0.3 s) | 4 blocks | starts after 8 ticks (0.4 s) · needs an input of at least 8 ticks (0.4 s) |
| 8 ticks (0.4 s) | 4 blocks | starts after 10 ticks (0.5 s) · needs an input of at least 15 ticks (0.75 s) |
| 10 ticks (0.5 s) | 8 blocks | starts after 1 tick (0.05 s) · needs an input of at least 20 ticks (1 s) |
| 16 ticks (0.8 s) | 13 blocks | starts after 4 ticks (0.2 s) · needs an input of at least 30 ticks (1.5 s) |
| 18 ticks (0.9 s) | 22 blocks | starts after 6 ticks (0.3 s) · needs an input of at least 40 ticks (2 s) |
| 24 ticks (1.2 s) | 13 blocks | starts after 4 ticks (0.2 s) · needs an input of at least 60 ticks (3 s) |
| 30 ticks (1.5 s) | 29 blocks | starts after 6 ticks (0.3 s) · needs an input of at least 40 ticks (2 s) |
| 32 ticks (1.6 s) | 13 blocks | starts after 4 ticks (0.2 s) · needs an input of at least 60 ticks (3 s) |
| 34 ticks (1.7 s) | 27 blocks | starts after 6 ticks (0.3 s) · needs an input of at least 80 ticks (4 s) |
| 40 ticks (2 s) | 13 blocks | starts after 4 ticks (0.2 s) · needs an input of at least 80 ticks (4 s) |
Try it
Hold IN under the view for a long press, tap it for a short one: the box marked OUT turns red while the output is on. Press play under the view to watch a demo on a loop; touch any other control to take over.
How this design does it: An observer watches a lamp that the input lights: the lamp turns on at once and goes off 4 ticks after the input, so the observer pulses 2 ticks on both edges even for the shortest input (2 ticks) (an observer facing the input itself needs 4).
Build it
Download .litematic Download the design as text
The .litematic opens in Litematica (Minecraft 26.3): every block of the design in one region. The text file is the same build written as plain text, block by block.
Blocks used: observer redstone lamp
Details: how it works, measurements and properties
In depth
Every time the input changes (turns on or turns off), the output gives one short pulse of L = 2 ticks (0.1 s), 2 ticks (0.1 s) rising / 6 ticks (0.3 s) falling after the change. It handles every input pulse of 2 ticks (0.1 s) (the shortest a real input makes) or longer.
Use it to react to any change of a lever, in both directions.
How to try it
Press play under the view to watch the demo on a loop (the badge reads demo with the step it is on; the same sequence is drawn as a timing diagram below). Touch any control to stop it and try the circuit yourself.
To try it: press and hold the IN button of the bar (or the cell tagged IN) to power that input; a quick tap sends a short 2-tick pulse.
Inputs are tagged in lime; the output is tagged OUT: the orange glass marker next to it glows while the output is on (the output strip by the demo badge shows its last 40 game ticks, 2 seconds). Drag to look around, pinch or scroll to zoom, step one game tick at a time with the step button.
Inputs and output over time
The input follows this schedule (the 3D view's demo plays the same). Lime: an input is on; orange: the output is on (taller = a stronger signal, 1 to 15). Time runs left to right in game ticks (20 ticks = 1 s).
Swipe the diagram sideways: the whole sequence lasts 425 ticks (21.25 s).
Step by step (11 lines)
in 2 ticks (0.1 s): +2 for 2, +8 for 2 in 3 ticks (0.15 s): +2 for 2, +9 for 2 in 4 ticks (0.2 s): +2 for 2, +10 for 2 in 5 ticks (0.25 s): +2 for 2, +11 for 2 in 6 ticks (0.3 s): +2 for 2, +12 for 2 in 8 ticks (0.4 s): +2 for 2, +14 for 2 in 10 ticks (0.5 s): +2 for 2, +16 for 2 in 15 ticks (0.75 s): +2 for 2, +21 for 2 in 20 ticks (1 s): +2 for 2, +26 for 2 in 30 ticks (1.5 s): +2 for 2, +36 for 2 in 40 ticks (2 s): +2 for 2, +46 for 2
Measurements
| metric | value | what it means |
|---|---|---|
| L | 2 ticks (0.1 s) | the length of the output pulse |
| delay | 2 ticks (0.1 s) rising / 6 ticks (0.3 s) falling | the time from the input's edge to the start of the output pulse |
| min-pulse | 2 ticks (0.1 s) (the shortest a real input makes) | the shortest input pulse handled correctly (every longer one works too) |
| tileable | every 1 (1 0 0) |
Notes from its designer
An observer watches a lamp that the input lights: the lamp turns on at once and goes off 4 ticks after the input, so the observer pulses 2 ticks on both edges even for the shortest input (2 ticks) (an observer facing the input itself needs 4). Read from the observer, copies stand side by side every block.
Properties
| Study | Pulse shapers |
|---|---|
| Kind | One pulse on every switch (dual-edge detector) |
| Blocks placed | 2 (not counting the input levers or buttons the view adds) |
| Box | 1×1×2 (2 blocks of space) |
| Made of (the blocks that change state) | observer, redstone lamp |
| Inputs / outputs | IN (repeater) / OUT |
| Flags | several versions of one mechanism |
| Design file | pulse-dual-edge-observer-lamp-L2 |
The design file
Design file (14 lines)
# One pulse on every switch: 2-tick pulse · 2 blocks # https://vjeux.github.io/redstonepedia/circuits/pulse/pulse-dual-edge-observer-lamp-L2.html name: pulse-dual-edge-observer-lamp-L2 circuit: dual-edge tile: 1 0 0 port input: 0 0 2 port output: 0 0 0 origin: 0 0 0 palette: O minecraft:observer[facing=south,powered=false] R minecraft:redstone_lamp[lit=false] layer 0: O R