Redstone components

Redstone components are the blocks used to build redstone structures. Redstone components include power components (such as redstone torches, buttons, and pressure plates), transmission components (such as redstone wire and redstone repeaters), and mechanism components (such as pistons, doors, and redstone lamps). Many redstone components must be "attached" to other blocks and will "pop" (turn into items) if their support is removed.

This article assumes familiarity with the basics of redstone structures; for details on terms and concepts, see redstone basics. This article also limits its discussion of each component to its role in redstone structures; for full details about a component, see the main article for the block.

Power components
Power components create redstone signals, either permanently or in response to player, mob, and environmental activity.

Power components may be either attached or placed. An attached power components strongly-powers the block it occupies and one other adjacent block (see below), while placed power components only strongly-power their own block. Strongly-powered blocks can turn ON adjacent redstone wire, redstone repeaters, and powered mechanisms.


 * Block of redstone
 * Usage: A block of redstone is used to provide a constant power source that can be moved by pistons.
 * Activation: A block of redstone is always ON.
 * Effect: A block of redstone turns ON adjacent redstone wire, redstone repeaters and redstone comparators facing away from it, and mechanism components. A block of redstone has no effect on adjacent opaque blocks.


 * Button
 * A button may be of two types: wooden or stone.
 * Usage: A button is used to generate a pulse.
 * Placement: A button can be attached to the side of most opaque blocks.
 * Activation: A player can turn a stone or wooden button ON by right-clicking it, and a wooden button can also be turned ON by a fired arrow. A stone button stays ON for 10 ticks (1 second), while a wooden button stays ON for 15 ticks (1.5 seconds) or, if turned ON by a fired arrow, until the arrow despawns after one minute or is picked up.
 * Effect: While ON, a button strongly-powers the block it is in, and the block it is attached to.


 * Daylight sensor
 * Usage: A daylight sensor is used to measure the "height" of the sun.
 * Activation: A daylight sensor turns ON at dawn and turns OFF at night.
 * Effect: While ON, a daylight sensor strongly-powers the block it is in, at a power level proportionate to the height of the sun in the sky.


 * Detector rail
 * Usage: A detector rail is used to detect the passage of a minecart.
 * Placement: A detector rail can be attached to the top of any opaque block, or to the top of an upside-down stair or upside-down slab.
 * When placed, a detector rail will configure itself to line up with adjacent rails, powered rails, and detector rails, as well as such adjacent rails one block up. If there are two such adjacent rails on non-opposite sides, or three or more such adjacent rails, a detector rail will line up in the east-west direction. If there are no such adjacent rails, a detector rail will line up in the north-south direction. If a rail it would line up with is one block up, a detector rail will slant upwards towards it (with multiple options to slant upwards to, a detector rail "prefers", in order: west, east, south, and north). Other configurations can be created by placing and removing various rail.
 * Activation: A detector rail turns ON when a minecart passes over it, and turns OFF when it leaves.
 * Effect: While ON, a detector rail strongly-powers the block it is in, and the block beneath it (unless placed on an upside-down stair or slab).


 * Lever
 * Usage: A lever is used to switch circuits on or off, or to permanently power a block.
 * Placement: A lever can be attached to the top, side, or bottom of most opaque blocks, or to the top of an upside-down stair or upside-down slab.
 * Activation: A player can turn a lever ON or OFF by right-clicking it.
 * Effect: While ON, a lever strongly-powers the block it is in, and the block it is attached to (unless attached to an upside-down stair or slab).


 * Pressure plate
 * A pressure plate may be of two types: wooden or stone.
 * Usage: A pressure plate is used to detect mobs, items, and other entities.
 * Placement: A pressure plate can be attached to the top of any opaque block, or to the top of a fence, nether brick fence, an upside-down stair or upside-down slab.
 * Activation: A pressure plate turns ON when an entity (mob, item, etc.) crosses or falls on it, and turns OFF when the entity leaves or is removed. A stone pressure plate is turned ON only by mobs (including players), while a wooden pressure plate is turned ON by mobs, items, and fired arrows. A wooden pressure plate turned ON by an item or fired arrow won't turn OFF until the item or arrow is picked up or despawns (after one minute for a fired arrow, or up to five minutes for an item).
 * Effect: While ON, a pressure plate strongly-powers the block it is in, and the block beneath it (unless placed on a fence, or an upside-down stair or slab).
 * Considerations: A pressure plate is not solid (it is not a barrier to entity movement). Usually a block under a pressure plate provides a solid barrier underneath it (for mobs to walk across, items to fall on, etc.), but when a pressure plate is placed on a block with a small collision mask, like a fence or nether brick fence, it is possible for entities to move through the pressure plate while still activating it. Thus, a pressure plate on a fence can be used to detect entities without stopping them (more compactly than a tripwire circuit).


 * Redstone torch
 * Usage: A redstone torch is used to power circuits, invert signals, and transmit power vertically.
 * Placement: A redstone torch can be attached to the top or side of any opaque block, or to the top of glass, fence, nether brick fence, cobblestone wall, an upside-down stair or upside-down slab.
 * Activation: A redstone torch stays ON until the block it is attached to is powered.
 * Effect: While ON, a redstone torch strongly-powers the block it is in and any opaque block above it (but not the block it is attached to).
 * Considerations: A redstone torch will "burn-out" (go dark and stop providing power) when it is forced to flicker on and off too quickly (by powering and de-powering the block it's attached to). After burning-out, a redstone torch will re-light when it receives a redstone update, or randomly after a short time.
 * One way to cause a burn-out is with a short-circuit -- using a torch to turn itself off, which then allows the torch to turn back on, etc. For example, if you place redstone wire on top of a block and a redstone torch on its side, then put another block above the torch, the torch will power the top block, which will turn on the adjacent redstone wire, which will power the block below it, turning the torch off -- this will cause the redstone torch to flicker and burn-out. When you need to put a torch under a block next to redstone wire, don't attach the torch to the block supporting the wire or you'll get burn-out.


 * Trapped chest
 * Usage: A trapped chest is used to detect player access of its contents.
 * Activation: A trapped chest is turned ON by one or more players accessing its contents.
 * Effect: While ON, a trapped chest strongly-powers the block it is in, and any opaque block below it, at a power level equal to the number of players accessing its contents (maximum 15).


 * Tripwire hook
 * Usage: A tripwire hook is used to detect mobs, items, and other entities over a large area.
 * Placement: A tripwire hook can be attached to the side of most opaque blocks.
 * In order to function correctly, a tripwire hook must be part of a tripwire circuit: a straight line of blocks consisting of an opaque block with a tripwire hook attached to it, a tripwire line (one or more blocks of tripwire), and a second tripwire hook attached to another opaque block. A tripwire circuit is placed correctly when the tripwire hook is fully extended and the tripwire runs continuously between the tripwire hooks. Tripwire lines from separate tripwire circuits can be placed next to each other (in parallel), above each other, and can even intersect each other.
 * Activation: A tripwire hook turns ON when an entity (mob, item, etc.) crosses or falls on the hook's tripwire line (but not the tripwire hook), and turns OFF when the entity leaves or is removed from the tripwire line. A tripwire hook also turns ON for 5 ticks when any of its tripwires are destroyed, except when using shears to "cut" the tripwire (breaking the tripwire hook, or the block it is attached to, also does not generate a pulse).
 * Effect: While ON, a tripwire hook strongly-powers the block it is in, and the block it is attached to. Tripwire provides no power itself.
 * Considerations: To place tripwire, right-click on an adjacent block with a string. Tripwire does not need to be supported when placed (it can be placed "floating" in the air), but if an opaque block (or upside-down slab or stair) directly underneath it is placed or removed, the tripwire will "pop" (turn back into string).


 * Weighted pressure plate
 * A weighted pressure plate may be of two types: light (gold) or heavy (iron).
 * Usage: A weighted pressure plate is used to measure the number of items on top of it.
 * Placement: A weighted pressure plate can be attached to the top of any opaque block, or to the top of a fence, nether brick fence, an upside-down stair or upside-down slab.
 * Activation: A weighted pressure plate is turned ON by one or more items on top of it.
 * Effect: While ON, a weighted pressure plate strongly-powers the block it is in, and the block beneath it (unless placed on a fence, or an upside-down slab or stair), at a power level proportionate to the number of items on top of it: items/4 for a light weighted pressure plate (round up; i.e., power level 1 for 1-4 items, power level 2 for 5-8 items, etc.), or 3*items/128 for a heavy weighted pressure plate (round up; i.e., power level 1 for 1-42 items, power level 2 for 43-85 items, etc.).

Transmission components
Transmission components propagate signals and pulses from power components to mechanism components. Complex effects can also be produced by allowing a signal to affect itself or its circuit.


 * Redstone comparator
 * Usage: A redstone comparator is used to compare or subtract two signals, or to measure how full a container is.


 * Placement: A redstone comparator can be attached to the top of any opaque block, or to the top of an upside-down stair or upside-down slab.


 * A redstone comparator has a front and a back &mdash; the arrow points from the back to the front. The comparator takes a signal from its back as its input, and outputs a signal to the block in front of it, but can also be affected by signals from its sides (see below).


 * A redstone comparator has two modes. Right-clicking a redstone comparator changes it between comparison mode (front torch down/off) and subtraction mode (front torch up/on).


 * Activation: A redstone comparator is turned ON by any powered component at its back, or by a non-empty container (as well as by container minecarts on a detector rail, a cauldron containing water, an end portal frame with an eye of ender, or a jukebox with a record) either at its back or separated from its back by an opaque block. It is not affected by blocks beneath it or above it, but its signal strength can be modified by signals from its sides (see below).


 * Effect: A powered redstone comparator turns ON redstone wire, a correctly-facing redstone comparator or redstone repeater, or a mechanism component in front of it, or strongly powers an opaque block in front of it -- all at the same power level as its input signal (unless modified by a side signal, see below). It has no effect on blocks in other adjacent positions (including the block beneath it).


 * The output of a redstone comparator can be affected by a signal provided from its side by a transmission component (redstone wire, redstone repeater, or another redstone comparator only):
 * In comparison mode, a redstone comparator only propagates its input signal if the input signal is greater than the side signal, and outputs no signal if not.
 * In subtraction mode, a redstone comparator outputs a power level equal to the power level of the input signal minus the power level of the side signal.


 * A redstone comparator activated by a container outputs a power level in proportion to how full the container is (rounded up, so a single item in a container will produce a power level of at least 1). A container's fullness is measured by stacks: for example, a single shovel (a non-stackable item), 16 signs, or 64 sticks are all considered to be full stacks and count equally towards a container's fullness.


 * The Comparator Output Table (right) shows the minimum stacks ("s") plus items ("i") required to produce a specific power level from a container. For example, to get power level 5 from a hopper, put 1 stack plus 28 items in the hopper. Divide items by 4 and round up for items with a stack maximum of 16. The values for the chest, dispenser, furnace and hopper apply to minecarts with those components as well (when on a detector rail).


 * Some blocks (such as crafting tables, enchantment tables, etc.) can hold items temporarily while the player uses the block's interface, but the items will be dropped if the player exits the interface with items still inside. Other blocks (such as beacons) can only consume items put in them. Putting items in these blocks will not activate a redstone comparator, even temporarily.


 * Redstone repeater


 * Usage: A redstone repeater is used to transmit power, re-strengthen redstone wire signals weakened by distance, delay a signal, and to give direction to redstone signal propagation.


 * Placement: A redstone repeater can be attached to the top of any opaque block, or to the top of an upside-down stair or upside-down slab.


 * A redstone repeater has a front and a back -- the arrow points from the back to the front. The repeater only reacts to signals from the block behind it and only propagates signals to the block in front of it (in the direction of the arrow). It also has an adjustable delay that can be set from 1 to 4 ticks by right-clicking it.


 * Activation: A redstone repeater is turned ON by any powered component at its back and is unaffected by the powered state of any block beside, above, below, or in front of it (but see below about "locking" a repeater).


 * Effect: A powered redstone repeater turns ON redstone wire or a mechanism component in front of it, or strongly powers an opaque block in front of it. It has no effect on the blocks under, above, beside, or behind it.


 * A redstone repeater not only "repeats" a signal (re-strengthens it for transmission), it also delays it by 1 to 4 ticks. A redstone repeater will also increase the duration of any pulse shorter than its delay to match the duration of its delay.


 * A redstone repeater can be "locked" by powering it from the side with another redstone repeater. A locked repeater will not change its output state until unlocked, even if its input changes.


 * Redstone wire


 * Usage: Redstone wire is used to transmit power.


 * Placement: Redstone wire is placed by right-clicking with redstone (dust is the item, wire is the block). Redstone wire can be attached to the top of any opaque block, or to the top of glowstone, an upside-down stair or upside-down slab.


 * When placed, redstone wire will configure itself to point towards adjacent redstone wire (at the same level or one level up or down), correctly-facing redstone repeaters, and power components. If there is only one such neighbor, redstone wire will form a line pointing towards and away from that one neighbor (which can cause it to point towards blocks it wouldn't normally point towards). If there are multiple such neighbors, redstone wire fill form either a line, an "L", a "T", or a "+". If there are no such neighbors, redstone wire will form a large directionless dot. Redstone wire won't automatically configure itself to point towards adjacent mechanism components, it must be arranged to do so.


 * When two redstone wires are placed vertically diagonally (one block over and one up, or one over and one down), the lower wire will appear to "crawl" up the side of the higher block to join the other wire. This linking can be "cut" by an opaque block above the lower wire, which prevents the two wires from connecting visually or transmitting power to each other. If the higher wire is on an upside-down stair or upside-down slab, the higher wire will configure itself to point towards the lower wire (and other adjacent wire), but the lower wire will not configure itself to point towards the higher wire (including not appearing to "crawl" up the side of the slab or stair).


 * The directions in which redstone wire configures itself can affect whether it powers adjacent opaque blocks and mechanisms.


 * Activation: Redstone wire can be turned ON by any adjacent power component, redstone repeater pointing at it, or strongly-powered opaque block. Redstone wire can also be turned ON by other adjacent powered redstone wire, but the power decreases with distance from a strongly-powered block. Redstone wire can transmit power up to 15 blocks.


 * Redstone wire can transmit power diagonally upwards to wire on an upside-down stair or upside-down slab, but not diagonally downwards from an upside-down stair or upside-down slab.


 * Effect: Powered redstone wire turns ON any mechanism component it is configured to point at. It will weakly-power an opaque block it is pointing at, or under it (supporting it).


 * Note: The in-game name for redstone placed as a block is "redstone dust", but for technical reasons the wiki is still using the old name "redstone wire".


 * Opaque blocks


 * Usage: Opaque blocks are used to support redstone components and to transmit power.


 * Activation: An opaque block is strongly powered by an active power component or an active redstone repeater, or weakly powered by active redstone wire above it or configured to point at it.


 * Effect: A powered opaque block turns OFF an attached redstone torch, turns ON an adjacent redstone repeater facing away from it, and turns ON an adjacent mechanism component. A strongly-powered opaque block will turn ON adjacent redstone wire, including redstone wire beneath the opaque block (but a weakly-powered opaque block will not).


 * Considerations: To attach redstone components to blocks you interact with by right-clicking (e.g., crafting table, furnace, dispenser, note block, and a jukebox containing a record), sneak while right-clicking.


 * Transparent blocks


 * Transparent blocks can not transmit power, but are only needed as "insulators" in very compact circuits because air works just as well. Some transparent blocks have special properties that make them useful in redstone circuits:


 * Glowstone: A redstone wire or fence gate can be attached or placed on the top of glowstone, and a trapdoor can be attached to the side of glowstone. A redstone wire on top of glowstone can transmit power to a redstone wire adjacent to it or diagonally upwards, but not diagonally downwards. Because glowstone is not opaque, it cannot power an adjacent block (including an attached trapdoor), but redstone wire on top of it can.


 * Slabs and stairs: A redstone torch, redstone wire, redstone repeater, lever, pressure plate (wooden or stone), rail (regular, powered, or detector), door (wooden or iron), and a fence gate can all be attached or placed on the top of an upside-down slab or upside-down stair, and a trapdoor can be attached to the side of an upside-down slab or stair (in single-player mode, a trapdoor cannot be placed on the "bottom" of an upside-down slab because there is no selection mask to interact with, but a slab moved to that position by a piston will not cause the trapdoor to pop). A redstone wire on top of an upside-down slab or upside-down stair can transmit power to a redstone wire adjacent to it or diagonally upwards, but not diagonally downwards. Because slabs and stairs are not opaque, they cannot be powered by power components and cannot provide power to adjacent blocks.


 * Glass and fences: A redstone torch can be attached to the top of glass, and a redstone torch or a pressure plate can be attached to the top of a fence or nether brick fence.

Mechanism components
Mechanism components are blocks which react to redstone power by affecting the environment -- by moving themselves or other entities, by producing light, sound, or explosions, etc.

Activation: All mechanism components are turned ON by:
 * an adjacent active power component (Exceptions: a redstone torch will not turn ON a mechanism component it is attached to, and a piston is not activated by a power component directly in front of it unless that component also powers the piston by connectivity)
 * an adjacent powered opaque block (strongly-powered or weakly-powered)
 * a powered redstone repeater facing the mechanism component
 * powered redstone wire configured to point at the mechanism component (or on top of it, for opaque mechanism components); a mechanism component is not turned ON by adjacent powered redstone wire which is not configured to point at it.

Connectivity: In addition to the methods above, dispensers, droppers, and pistons can also be turned ON if one of the methods above would activate a mechanism component in the block above the component, even if there is no mechanism component there (even if the block above the component is air or a transparent block), but only when the component receives a block update (including a redstone update within two blocks of the component). This rule is often simplified to saying that the components can be powered by blocks diagonally above or two blocks above, but other methods of activation by connectivity exist (see image to the right). This method of activation is also known as "quasi-connectivity" (the piston is seemingly "connected" to the block above for the purposes of activation) or "piston quasi-connectivity" (as it originated with pistons).

Activation vs. Powered: For opaque mechanism components (command blocks, droppers, dispensers, note blocks, redstone lamps, and TNT), it's important to make a distinction between a mechanism component being activated (so that it performs an action) and being powered (so that a redstone signal could be drawn from it by a transmission component). Any method of powering a mechanism component (such as a redstone torch underneath it) will also activate it, but some activation methods (such as a redstone torch next to or above a mechanism component) won't actually power the component (following the usual rules for power components).


 * Activator rail
 * Usage: An activator rail is used to activate a minecart.
 * Placement: An activator rail can be attached to the top of any opaque block, or to the top of an upside-down stair or upside-down slab.
 * When placed, an activator rail will configure itself to line up with adjacent rails, activator rails, powered rails, and detector rails, as well as such adjacent rails one block up. If there are two such adjacent rails on non-opposite sides, or three or more such adjacent rails, an activator rail will line up in the east-west direction. If there are no such adjacent rails, an activator rail will line up in the north-south direction. If a rail it would line up with is one block up, an activator rail will slant upwards towards it (with multiple options to slant upwards to, an activator rail "prefers", in order: west, east, south, and north). Other configurations can be created by placing and removing various rail.
 * Activation: In addition to the methods above, an activator rail can also be activated by other adjacent activated activator rail. Activator rail can transmit activation up to 9 rails (the first originally-activated activator rail, and up to eight additional activator rails). Activation transmitted in this way cannot power any redstone components except activator rail.
 * Effect: An activator rail affects certain minecart passing over it. The effects vary with the type of minecart activated:
 * A minecart with TNT will be ignited by an active activator rail.
 * A minecart with hopper will be deactivated by an active activator rail (it will stop sucking up items in its path, or transferring items to containers as it passes them), and re-activated by an inactive activator rail.
 * Other minecarts are not affected by an activator rail.


 * Command block
 * Command blocks can only be obtained with the command.
 * Usage: A command block is used to execute a server command.
 * Placement: After being placed, the player can set the command to be executed by right-clicking on the command block.
 * Effect: When activated, a command block executes its defined command once.
 * Like other mechanism components, an already-activated command block will not respond to other redstone signals. To make a command block execute its defined command more than once it must be deactivated and re-activated repetitively.


 * Dispenser
 * Usage: A dispenser is used to interact with the environment with items.
 * Activation: See Connectivity above.
 * Effect: The effects of being activated vary with the items in the dispenser:
 * {| class="collapsible wikitable"

! colspan=2 | Dispenser Behavior ! Item ! Effect
 * Equips on a player within a one-block distance (any armor, made from any material)
 * Fired in the direction the dispenser is facing, as if the player had right-clicked a bow in their inventory
 * Placed as entity (i.e., a right-clickable vehicle) in the block the dispenser is facing, if the dispenser is facing water or an empty block above water &mdash; otherwise dropped (see below)
 * Increments the growth stage of carrots, cocoa pods, crops, melon stems, potatoes, pumpkin stems, and saplings the dispenser is facing; grows grass, dandelions, and roses, if the dispenser is facing a grass block; grows a huge brown mushroom if facing a brown mushroom
 * Fired in the direction the dispenser is facing, as if the player had right-clicked a bow in their inventory
 * Placed as entity (i.e., a right-clickable vehicle) in the block the dispenser is facing, if the dispenser is facing water or an empty block above water &mdash; otherwise dropped (see below)
 * Increments the growth stage of carrots, cocoa pods, crops, melon stems, potatoes, pumpkin stems, and saplings the dispenser is facing; grows grass, dandelions, and roses, if the dispenser is facing a grass block; grows a huge brown mushroom if facing a brown mushroom
 * Placed as entity (i.e., a right-clickable vehicle) in the block the dispenser is facing, if the dispenser is facing water or an empty block above water &mdash; otherwise dropped (see below)
 * Increments the growth stage of carrots, cocoa pods, crops, melon stems, potatoes, pumpkin stems, and saplings the dispenser is facing; grows grass, dandelions, and roses, if the dispenser is facing a grass block; grows a huge brown mushroom if facing a brown mushroom
 * Increments the growth stage of carrots, cocoa pods, crops, melon stems, potatoes, pumpkin stems, and saplings the dispenser is facing; grows grass, dandelions, and roses, if the dispenser is facing a grass block; grows a huge brown mushroom if facing a brown mushroom
 * Increments the growth stage of carrots, cocoa pods, crops, melon stems, potatoes, pumpkin stems, and saplings the dispenser is facing; grows grass, dandelions, and roses, if the dispenser is facing a grass block; grows a huge brown mushroom if facing a brown mushroom
 * Increments the growth stage of carrots, cocoa pods, crops, melon stems, potatoes, pumpkin stems, and saplings the dispenser is facing; grows grass, dandelions, and roses, if the dispenser is facing a grass block; grows a huge brown mushroom if facing a brown mushroom


 * Fired in the direction the dispenser is facing, as if the player had right-clicked the item in their inventory
 * Collects lava or water the dispenser is facing (replacing the empty bucket in the dispenser with a lava or water bucket) &mdash; otherwise dropped (see below)
 * Ignites the block the dispenser is facing; reduces the remaining durability of the used flint and steel
 * Collects lava or water the dispenser is facing (replacing the empty bucket in the dispenser with a lava or water bucket) &mdash; otherwise dropped (see below)
 * Ignites the block the dispenser is facing; reduces the remaining durability of the used flint and steel
 * Ignites the block the dispenser is facing; reduces the remaining durability of the used flint and steel
 * Ignites the block the dispenser is facing; reduces the remaining durability of the used flint and steel


 * Places lava or water in the block the dispenser is facing (replacing the lava or water bucket in the dispenser with an empty bucket), if the block the dispenser is facing is one that the player could use a lava or water bucket on (e.g., air, flowers, grass, etc.) &mdash; otherwise dropped (see below)


 * Placed as entity (i.e., a right-clickable vehicle) in the block the dispenser is facing, if the dispenser is facing a type of rails &mdash; otherwise dropped (see below)
 * Places and ignites TNT in the block the dispenser is facing
 * Others
 * Dropped: ejected towards the block the dispenser is facing, as if the player had used the Drop control (default )
 * }
 * If the dispenser is facing a container, the ejected item will simply be transferred into the container.
 * Considerations: A dispenser is an opaque block, so powering it directly can cause adjacent mechanism components (including other dispensers) to activate as well.
 * }
 * If the dispenser is facing a container, the ejected item will simply be transferred into the container.
 * Considerations: A dispenser is an opaque block, so powering it directly can cause adjacent mechanism components (including other dispensers) to activate as well.


 * Door
 * A door may be of two types: a wooden door can be opened and closed by redstone power or by a player right-clicking on it, while an iron door can only be opened and closed by redstone power.
 * Usage: A door is used to control or prevent the movement of mobs, items, boats, and other entities.
 * Placement: A door can be attached to the top of most opaque blocks, or to the top of an upside-down slab or upside-down stair.
 * A door is placed on the edge of the block facing the player. By default the door's hinge will be on the left side, but another door or block can force the hinge to the right side.
 * Effect: While activated, a door re-positions to the other side of its hinge, allowing movement through its former position and denying movement through its current position. When activated, any entities on the door will fall.
 * A door doesn't actually "move" (the way a piston arm or a pushed block moves), it simply disappears from one side and re-appears on another, so it won't push entities as it "opens".


 * Dropper
 * Usage: A dropper is used to eject items or push them into containers (including other droppers).
 * Placement: A dropper can be placed so that its output faces in any direction.
 * Activation: See Connectivity above.
 * Effect: When activated, a dropper ejects a random item in the direction the dropper is facing, as if the player had used the Drop control. If the dropper is facing a container, the ejected item will be transferred into the container.
 * Considerations: A dropper is an opaque block, so powering it directly can cause adjacent mechanism components (including other droppers) to activate as well.


 * Fence gate
 * Usage: A fence gate is used to control or prevent the movement of mobs, items, boats, and other entities.
 * Placement: A fence gate can be placed on the top of most blocks. Once placed, the block beneath it may be removed without popping the fence gate.
 * Effect: While activated, a fence gate re-positions its two gates to either side, allowing movement through it. When activated, any entities on the fence gate will fall.
 * A fence gate doesn't actually "move" (the way a piston arm or a pushed block moves), it simply disappears from one state and re-appears in another, so it won't push entities as it "opens".
 * Unlike a door or trapdoor, while active, a fence gate is completely non-solid (lacks a collision mask) to all entities.


 * Hopper
 * Usage: A hopper is used to move items to and from containers (including other hoppers).
 * Placement: A hopper can be placed so that its output faces in any direction except up.
 * Effect: While not activated, a hopper transfers items from a container above it into its own slots and transfers items from its own slots into a container it is facing. Both types of transfers occur every 4 redstone ticks (0.4 seconds), and pulls are processed before pushes. While activated, a hopper does not pull items from above or push them out, but may receive items from other mechanism components and may have its items removed by another hopper beneath it.


 * Note block
 * Usage: A note block is used to produce a player-chosen sound.
 * Placement: After being placed, a note block's pitch can be adjusted over a two-octave range by right-clicking the note block, and its "instrument" can be adjusted by placing different blocks beneath it.
 * Effect: When activated, a note block produces a sound. A note block must have air above it to activate.
 * Considerations: A note block is an opaque block, so powering it directly can cause adjacent mechanism components (including other note blocks) to activate as well.


 * Piston
 * A piston may be of two types: a regular piston only pushes blocks, while a sticky piston pushes and pulls blocks.
 * Usage: A piston is used to move blocks or entities. May be part of a circuit's output (such as a circuit built to control a piston door), or may be incorporated within the circuit to change a circuit's configuration (for example, by moving an opaque block over a redstone torch or away from it).
 * Placement: A piston has a stone "pushing" component and a wooden "arm", and can be placed so the arm faces in any direction (its "front").
 * Activation: See Connectivity above.
 * Effect: When activated, a piston pushes the block in front of its arm, and up to 11 more blocks in front of that (up to 12 blocks total). When deactivated, a regular piston pulls its arm back (leaving an air block in front of the piston), while a sticky piston pulls back both its arm and one block (leaving an air block on the other side of the pulled block).
 * A moving piston or block can also push an entity such as a mob or item.
 * Some blocks (bedrock, obsidian, chests, etc.) cannot be moved by a piston. Other blocks (flowers, leaves, torches, etc.) will be destroyed but may drop items (as if destroyed by the player). For full details of how pistons interact with other blocks, see Pushing Blocks.
 * Considerations: When a sticky piston is activated by a 1-tick pulse, it will push a block in front of it, but will fail to pull back the pushed block on the same pulse. If a sticky piston is activated by a 1-tick pulse when there is no block in front of it, it can pull back a block. Thus, a sticky piston running on 1-tick pulses will push and pull a block every other pulse.


 * Powered rail
 * Usage: A powered rail is used to propel a minecart.
 * Placement: A powered rail can be attached to the top of any opaque block, or to the top of an upside-down stair or upside-down slab.
 * When placed, a powered rail will configure itself to line up with adjacent rails, powered rails, and detector rails, as well as such adjacent rails one block up. If there are two such adjacent rails on non-opposite sides, or three or more such adjacent rails, a powered rail will line up in the east-west direction. If there are no such adjacent rails, a powered rail will line up in the north-south direction. If a rail it would line up with is one block up, a powered rail will slant upwards towards it (with multiple options to slant upwards to, a powered rail "prefers", in order: west, east, south, and north). Other configurations can be created by placing and removing various rail.
 * Activation: In addition to the methods above, a powered rail can also be activated by other adjacent activated powered rail. Powered rail can transmit activation up to 9 rails (the first originally-powered powered rail, and up to eight additional activated rails). Activation transmitted in this way cannot power any redstone components except powered rail.
 * Effect: While activated, a powered rail boosts the speed of a minecart passing over it, or starts a minecart moving away from an adjacent solid block it is in contact with.


 * Rail
 * Usage: A rail is used to switch the track of a minecart.
 * Placement: A rail can be attached to the top of any opaque block, or to the top of an upside-down stair or upside-down slab.
 * When placed, rail will configure itself to line up with adjacent rails, powered rails, and detector rails, as well as such adjacent rails one block up. If there are two such adjacent rails on non-opposite sides, the rail will curve from one to the other. If there are three or four such adjacent rails, the rail will curve between two of them (when choosing which directions to curve between, a rail "prefers" south over north, and east over west). If there are no such adjacent rails, the rail will line up in the north-south direction. If a rail it would line up with is one block up, a rail will slant upwards towards it without curving (with multiple options to slant upwards to, a rail "prefers", in order: west, east, south, and north). Other configurations can be created by placing and removing various rail.
 * Effect: While activated, a rail in a "T" junction flips to curve the other way (activating a rail in another configuration has no effect).


 * Redstone lamp
 * Usage: A redstone lamp is used to provide light.
 * Activation: A redstone lamp activates normally, but takes 2 ticks to deactivate.
 * Effect: While activated, a redstone lamp has block light level 15 (so produces block light level 14 in all adjacent transparent spaces).
 * Considerations: A redstone lamp is an opaque block, so powering it directly can cause adjacent mechanism components (including other redstone lamps) to activate as well.


 * TNT
 * Usage: TNT is used to create an explosion.
 * Activation: In addition to the methods above, TNT can also be activated by fire and explosions.
 * Effect: When activated, TNT ignites and becomes primed TNT, an entity which can fall like sand or be pushed by pistons (but isn't moved by water). Primed TNT explodes 40 ticks (4 seconds) after being ignited by redstone power (10-30 ticks for TNT ignited by an explosion).


 * Trapdoor
 * Usage: A trapdoor is used to control or prevent the movement of mobs, items, boats, and other entities.
 * Placement: A trapdoor can be attached to the top or the bottom of the side of most opaque blocks, as well as to glowstone, slabs, and stairs.
 * Slabs lack a full-side interaction mask -- to attach a top trapdoor to a bottom slab, or a bottom trapdoor to a top slab, attach the trapdoor to another block and then use a piston to move the trapdoor into position with the slab, or move the slab into position with the trapdoor.
 * Effect: While activated, a trapdoor re-positions itself in a vertical state, allowing vertical movement through it. When activated, any entities on the trapdoor will fall.
 * A trapdoor doesn't actually "move" (the way a piston arm or a pushed block moves), it simply disappears from one state and re-appears in another, so it won't push entities as it "opens".

Mobile components

 * Boat
 * Usage: A boat is used to transport a player over water.
 * Behavior: While inside a boat, the player can move it with the movement control keys. A boat is also moved by flowing water, and will rise rapidly when submerged underwater.


 * Minecart
 * Usage: A minecart is used to transport a mob or player over rails.
 * Behavior: The player can move a minecart by pushing against it while outside the minecart (whether the minecart is on rails or not), or by pressing the Forward control key (by default, W) while inside the minecart (only while the minecart is on rails). A minecart resting on powered rails configured to point at an adjacent opaque block will be propelled away from the opaque block when the powered rails are activated. A minecart traveling over powered rails will have its speed boosted.


 * Minecart with chest
 * Usage: A minecart with chest (a.k.a. chest minecart, storage minecart) is used to store and transport items over rails.
 * Behavior: A minecart with chest will accept items from a hopper and will allow a hopper underneath it to pull items from it.


 * Minecart with furnace
 * Usage: A minecart with furnace (a.k.a. furnace minecart, powered minecart) is used to push other minecarts over rails.
 * Behavior: A minecraft with furnace will propel itself and other minecarts without requiring powered rails.


 * Minecart with hopper
 * Usage: A minecart with hopper (a.k.a. hopper minecart) is used to collect, transport, and distribute items over rails.
 * Behavior: A minecart with hopper will pull items from containers above it and push items into hoppers below it (the number of items that will be transferred can depend on how long its velocity allows it to remain within reach of the containers). It will also pick up items that have fallen on the rails. If a minecart with hopper passes over a powered activator rail, it will stop transferring items indefinitely until it passes over an unpowered activator rail.


 * Minecart with TNT
 * Usage: A minecart with TNT (a.k.a. TNT minecart) is used to create explosions.
 * Behavior: A minecart with TNT which passes over a powered activator rail will explode( explosions from TNT minecarts will not damage rails or the blocks supporting rails).