Redstone Builds
Redstone contraptions, doors, traps, flying machines, and logic circuits.
A 3x3 flush piston door that opens and closes seamlessly with the wall. All 9 blocks retract into the floor and ceiling when activated, creating a clean passageway. Uses a precise timing sequence of sticky pistons.
A self-propelling machine that builds a bridge as it moves forward. It rides on a flying machine core of observers, sticky pistons and slime blocks.
A compact flying machine using observer-piston loops to travel indefinitely in one direction. Can be used for transportation or as a base for TNT bombers.
A 2x2 flush hidden piston door that sits flush with a stone wall. Activated by levers on both sides for easy entry and exit.
A collection of clock circuit designs that output a repeating redstone signal at configurable intervals. Includes repeater clocks (fastest), hopper clocks (long delays), and comparator clocks (silent). Used to power dispensers, droppers, and any mechanism needing periodic activation.
A slime block elevator that launches players upward using piston-slime mechanics. Features call buttons on each floor and a safe landing pad.
A massive 3x3 vault door that opens dramatically with timed piston sequences. Uses repeater delays for a cinematic opening and closing animation.
A hidden entrance behind a painting. Place signs on the wall to hold the painting, leaving a 1-block gap you can walk through. The simplest secret door in Minecraft.
A self-propelled flying machine using observers and pistons on slime blocks. The observer feedback loop creates continuous motion in one direction. Used for world eaters, TNT bombers, chunk loaders, and transportation.
A toggle circuit that alternates between on and off with each button press. Essential for creating button-activated piston doors, lights, and any mechanism that needs a persistent toggle state from a momentary input.
A functional TNT cannon that launches a primed TNT block over 60 blocks. Uses water to protect the cannon body while charge TNT provides the propulsion force.
Signal strength and timing
A lever, a redstone torch or a block of redstone gives a signal of strength 15, and redstone dust loses one level of it for every block it crosses, so a line of dust carries a signal 15 blocks at most. A repeater sends the signal on at full strength again and adds a delay: every click adds 2 game ticks, from 2 up to 8, which is 0.1 to 0.4 seconds. Power a repeater from the side with another repeater or a comparator and it locks in the state it is in.
- Comparator
- Passes on the signal from its back unless a side input is stronger. With its front torch lit it subtracts the stronger side signal from the back one instead. It can also read how full a container is, and crafting one takes nether quartz.
- Observer
- Watches the block in front of its face. When that block changes, the observer sends a pulse of strength 15 out of its back for 2 game ticks, and two observers watching each other make a fast, compact clock.
- Redstone torch
- Inverts a signal: the torch switches off while the block it is attached to is powered. A torch forced off more than eight times in 3 seconds burns out and usually stays off until a block update lights it again.
- Hopper
- Moves one item every 8 game ticks, 0.4 seconds, and a redstone signal stops it. Hopper clocks keep time with that steady rate.
The redstone clock circuits build covers repeater, hopper, comparator and observer clocks. Its repeater clock, two repeaters in a loop of dust, pulses every 4 game ticks at the shortest delay and slows down as you add repeaters or delay.
Pistons, slime and honey
A piston pushes at most 12 blocks. Obsidian and a few other blocks can't be moved at all, and in Java neither can furnaces, chests or other blocks that store data. Some blocks break instead of moving, and when a push is blocked, the piston simply doesn't extend.
- Sticky pistons
- Pull the block back when they retract. In Java, a pulse of 1 game tick or less makes a sticky piston let go and leave the block where it pushed it, which players call block dropping.
- Slime and honey blocks
- Both drag along the blocks touching them, but they never stick to each other and neither moves glazed terracotta. That lets two parts of a machine sit side by side and still move separately. The 12 block limit counts every block that moves.
- What happens to riders
- A slime block pushed by a piston launches the players and mobs in front of it, while honey carries the ones on top along and stops them jumping high. In Java honey doesn't carry a redstone signal and slime does.
- Quasi-connectivity
- In Java a piston can also be powered through the space above it, and a piston powered that way doesn't always react until it gets a block update. That is why pistons sometimes move for a lever or dust that doesn't seem to touch them.
Flying machines work because an observer sends a pulse after a piston moves it, so observers and pistons keep shoving each other along. Get the simple flying machine going before the flying machine, and put a block pistons can't move in its path where you want it to stop. The redstone elevator and the auto bridge builder are built on the same pistons, observers and slime.
Toggles, doors and secret entrances
A T flip-flop turns a button into an on and off switch, because every pulse flips its output. The simplest one is a copper bulb with a comparator reading it, since the bulb itself switches on or off with each pulse. The T flip-flop circuit build does the same with a sticky piston, and either kind lets a button open and close the hidden piston door or the 3x3 flush piston door. The redstone vault door adds repeater delays so its pistons fire one after another.
The secret painting entrance needs no redstone. A painting can hang on signs, and players and mobs walk straight through a painting when the blocks behind it let them. Mobs find their way through too, so it hides a doorway from other players, not from zombies.
TNT and water
Lit TNT explodes after 80 game ticks, 4 seconds, and until then water, pistons and other explosions can push it. TNT that explodes in water usually doesn't destroy blocks, but the blast still throws lit TNT nearby. The TNT cannon relies on both: its charge goes off in water without harming the cannon and launches the TNT in front of it.