Observer

In this piece, we delve into the world of blocks that have the ability to detect updates. It’s important to note that this is distinct from the block update detector used

A keen observer, in the form of a block, exudes a swift redstone pulse from its posterior region as soon as any block or fluid located right before its “face” undergoes any alteration.

Obtaining[]

Breaking[]

To extract its treasures, a spectator must wield a pickaxe. If stripped of this crucial tool, the mine will yield no rewards.

Block	Observer
Hardness	3
Tool
Default	15
Wooden	2.25
Stone	1.15
Iron	0.75
Diamond	0.6
Netherite	0.5
Golden	0.4

Crafting[]

Ingredients	Crafting recipe
Cobblestone + Redstone Dust + Nether Quartz

Usage[]

Like a piston, the observer is positioned to keep a watchful eye on a block. The detecting side bears a resemblance to an observant face. With the ability to detect the status of other observers, strategically placing two observers side by side, each monitoring the other, can produce a swift and space-saving redstone clock. A pulse is emitted as a result.

Behavior[]

The Java Edition’s observer is designed to detect any alteration made to the target’s block states, whether it’s the placement or removal of a block. However, it only monitors changes in block state and not the block entity data. This unique feature enables it to track even the slightest transformation such as the growth of crops, which is reflected in the block states.

The Bedrock Edition features a unique observer that functions as a vigilant block update sensor, dutifully detecting and responding to any and all block updates.

Java Edition and Bedrock Edition have distinct causes and modes of spreading block updates, leading to a divergence in their ability to detect particular types of alterations. A comparative view of their differences is presented in the table below.

The pulse in Java Edition has a one redstone tick delay, while in Bedrock Edition it is intended to be delayed by one tick but is actually delayed by two redstone ticks because of a bug known as MCPE-15793. This bug causes redstone delays to be incorrect when components are activated by world changes, which is the only way the observer in Bedrock Edition can be activated. This timing issue can also be compounded by MCPE-73342.

Moving the observer by a piston also qualifies as a block update. As a result, the observer releases a pulse only after being pushed or pulled, not before. This unique feature makes it possible to incorporate them into flying machines.

The enigmatic nature of observers is truly fascinating, for they possess the ability to act as both a barrier and a pathway. While they may obstruct the flow of light and permit the birth of monsters above, they remain powerless against the opening of chests below and the transmission of redstone currents.

The beauty of observers in Java Edition lies in their ability to detect a multitude of phenomena that a block update detector (BUD) circuit simply cannot. This is due to the fact that they pick up on changes in the block state, rather than just block updates. In stark contrast, observers in Bedrock Edition are only able to detect block updates and not block state changes, rendering them identical to any other BUD in that particular edition.

Limitations[]

The Bedrock Edition information is conspicuously absent from this piece.

Kindly enrich the article by incorporating this valuable information. It is possible that more intricate particulars can be found on the discussion page.

Change in block state	Detected in
Bedrock Edition	Java Edition
A block or a fluid being placed or broken in any way; either directly by player, enderman, or ravager or through: Placing/breaking two-block-tall/wide blocks Snow golem or snowfall creating snow Snow melting Dispenser placing carved pumpkin, wither skull, or shulker box Creating/removing fluid using player or dispenser Placing scaffolding on top/side of another scaffolding Entities that is on fire touching powder snow, causing it to melt Flammable blocks getting burned up by fire or lava A falling block turn into a falling block entity and vice versa Cactus breaking by placing a solid block next to it Villager planting and destroying crops Zombie breaking doors Leaves decaying Using up a damaged anvil, causing the damaged anvil to break Eating all the cake Water touching a sponge, causing the area near the sponge to be removed and create a block update to the water Place the block into the replaceable block, replace a block by left-click and right-click at the same time; A wither rose block being planted after wither kills a mob if the ground is grass block, dirt, coarse dirt, moss block, mud, soul sand, soul soil‌[JE only] or netherrack Left-clicking the dragon egg, causing it to teleport and create a block update at the starting teleporting point and the teleporting destination of the dragon egg Boat and boat with chest breaking a lily pad Turtle laying turtle egg(s), trampling an eggs=1 turtle egg or turtle egg(s) hatching into baby turtle(s) Damaging a silverfish, causing a nearby infested block turn into silverfish and create a block update Frog laying frogspawn or frogspawn hatch into tadpole Thrown trident breaks pointed dripstone Sniffer egg hatch into snifflet The upper part of pitcher crop spawn when apply bone meal on the pitcher crop that have block state age is 2	Yes	Yes
Water being inserted to or removed from a block that can be waterlogged.	Yes	Yes
A water (or lava) source block being created by having 2 water (or lava) source blocks unite to each other when the game rule waterSourceConversion (or lavaSourceConversion) is set to true.	N/A	Yes
Fire being ignited or extinguished in any way; either directly by player or through: A dispenser Fire spreading to flammable blocks next to lava or fire Fireball from a dispenser, a ghast or a blaze Lightning A bed or a respawn anchor exploding Place an end crystal on bedrock or obsidian in the End Being extinguished by fluid, splash water bottle, lingering water bottle or naturally	Yes	Yes
A fire is turn into a soul fire (but not vice versa).	N/A	Yes
Fluid or powder snow being placed in or removed from a cauldron or the level of the water/lava/powder snow cauldron changing in any way, for example using bucket (empty, water, lava, powder snow), bottle, water bottle, rain, snowfall, pointed dripstone, burning entity on water/powder snow cauldron.	N/A	Yes
Block being replace by /setblock, /fill or /clone commands.	N/A	Yes
Change block state of block using debug stick.‌[Java Edition only]	N/A	No
A nether portal being created.	N/A
A nether portal being destroyed.	Yes
An end portal being created.	N/A	No
An end portal being destroyed.	N/A	Yes
The creation of an iron golem, a snow golem or a wither.	N/A	Yes
A (sticky) piston (head) extending or retracting.	Yes	Yes
N/A	Yes
A monster spawner block activating.	No	No
The mob spawn of a monster spawner being changed using a spawn egg.	No	No
A chest, a trapped chest or an ender chest opening or closing.	No	No
A shulker box opening or closing.	No	Yes
A barrel opening or closing.	Yes	Yes
The inventory of a block that a comparator can measure as a container changing.	No	No
The crack stage of an anvil changing after use.	Yes	Yes
A snow layer being added into snow by player or by snowfall when the game rule snowAccumulationHeight‌[JE only] is larger than 1.	Yes	Yes
A beacon activating or deactivating.	Yes	No
A command block producing a success.	No	No
The unconditional/conditional stage of a command block changing.	N/A	Yes
The impulse/chain/repeat stage of a command block changing.	N/A	Yes
A piece of a cake or a cake with candles changing.	Yes	Yes
A hopper being activated or deactivated. (Turning the hopper on/off)	Yes	Yes
Dry farmland changing between its six dry-looking hydration stages.	No	Yes
Farmland changing between dry and humid or vice versa.	Yes	Yes
A dispenser or a dropper activating or deactivating.	Yes	Yes
No	Yes
A (deepslate) redstone ore block activating or deactivating.	Yes	Yes
Grass block or mycelium turning to dirt or nylium to netherrack after being spread using bone meal or grass block or mycelium decaying to dirt or nylium into netherrack.	Yes	Yes
Coarse dirt or rooted dirt converting into dirt through the use of a hoe.	Yes	Yes
Grass block, dirt, or dirt path converting into farmland through the use of a hoe.	Yes	Yes
Grass block, podzol, mycelium, dirt, coarse dirt, or rooted dirt converting into dirt path through the use of a shovel.	Yes	Yes
Farmland or dirt path converting into dirt.	Yes	Yes
Concrete powder converting into concrete through contact with water.	N/A	Yes
A sea pickle being added into a sea pickle.	Yes	Yes
A pink petal being added into a pink petal.	N/A	Yes
A turtle egg being added into a turtle egg.	Yes	Yes
A turtle egg being removed from a turtle egg by breaking or trampling.	Yes	Yes
The hatch block state of a turtle egg and a sniffer egg changing.	N/A	Yes
A stone, cobblestone, deepslate or any stone brick variant block being turned into an infested block by silverfish.	Yes	Yes
A double slab being created by adding a slab into another slab.	Yes	Yes
Ice melting into water or water freezing into ice	N/A	Yes
Water freezing into frosted ice through the use of Frost Walker or frosted ice melting into water	N/A	Yes
Turn pumpkin into carved pumpkin using shears.	N/A	Yes
Turn logs/woods/stems/hyphae/block of bamboo into stripped logs/woods/stems/hyphae/block of stripped bamboo using axes.	N/A	Yes
The stage of a sapling or bamboo changing.	N/A	Yes
The age of mangrove propagules, bamboo, wheat, carrots, potatoes, beetroots, melon stem, pumpkin stem, nether wart, cocoa, sweet berry bush, chorus flower, cactus, sugar cane, kelp, weeping vines, twisting vines, cave vines, fire, frosted ice, torchflower crop, or pitcher crop changing.	Yes	Yes
A torchflower crop turning into a torchflower.	N/A	Yes
Yes	Yes
Fluid, light block, or composter level changing.	Yes	Yes
(Flowing) water turning into stone through contact with lava.	N/A	Yes
Flowing lava turning into cobblestone through contact with water.	N/A	Yes
Lava turning into obsidian through contact with water.	N/A	Yes
(Flowing) lava turning into basalt through contact with soul soil and blue ice.	N/A	Yes
Water turning into bubble column or vice versa.	N/A	Yes
Upward bubble column turning into whirlpool bubble column or vice versa.	N/A	Yes
An eye of ender being inserted into an end portal frame.	N/A	Yes
Player or villager sleeping/waking up in a bed.	N/A	Yes
A grass block, a mycelium or a podzol block becoming snowy or not snowy.	Yes	Yes
Text in a sign or a hanging sign being edited.	Yes	No
A dye or glow being applied to a sign or a hanging sign or removed from it.	Yes	No
Waxing a sign or a hanging sign using a honeycomb.	N/A	No
The mode of a structure block or a comparator changing.	N/A	Yes
A grass block, grass‌[BE only] or fern‌[BE only] being grazed by a sheep.	N/A	Yes
A carrot crop being eaten by a rabbit.	N/A	Yes
A button being pressed or returning to inactive state.	Yes	Yes
A pressure plate or the detector rail activating or returning to inactive state.	N/A	Yes
The power of a weighted pressure plate, redstone wire, daylight detector or target changing.	N/A	Yes
A lever being flicked.	Yes	Yes
A redstone lamp or a redstone torch lighting up or turning off.	N/A	Yes
The mode of daylight detector being changed.	N/A	Yes
A TNT igniting.	N/A	Yes
Coral/coral block/coral fan converting into dead coral/coral block/coral fan.	N/A	Yes
A sponge turning into a wet sponge.	N/A	Yes
A wet sponge drying into a sponge in the Nether	N/A	N/A
A water block being vaporize in the Nether.	N/A	N/A
A door being opened or closed by a player, a villager, a piglin, a piglin brute, a vindicator‌[JE only], a wandering trader‌[BE only] or redstone.	Yes	Yes
A trapdoor being opened or closed by a player or redstone.	N/A	Yes
A fence gate being opened or closed by a player or redstone.	N/A	Yes
The in_wall block state of a fence gate changing.	N/A	Yes
A furnace, a blast furnace or a smoker lighting up or turning off.	N/A	Yes
The distance of leaves or a scaffolding changing.	N/A	Yes
The bottom block state of a scaffolding changing.	N/A	Yes
A potion being moved in or out of a brewing stand.	Yes	Yes
Book and quill or written book being moved in or out of a lectern.	Yes	Yes
The note of a note block being changed.	No	Yes
A note block being left-clicked in Survival mode.	N/A	No
The instrument block state of a note block changing.	No	Yes
A music disc being inserted to or removed from a jukebox by player, hopper, or minecart with hopper.	N/A	Yes
A redstone repeater locking or unlocking.	Yes	Yes
The delay of a redstone repeater being changed.	Yes	Yes
N/A	Yes
A tripwire or a tripwire hook attached or detaching.	N/A	Yes
The disarmed block state of a tripwire changing.	N/A	N/A
Sculk shrieker shrieking or stopping shrieking.	N/A	Yes
Sculk catalyst blooming or unblooming.	N/A	Yes
A dragon head or a piglin head activating or deactivating.	Yes	No
A conduit activating or deactivating.	N/A	N/A
An item frame being placed or an item being added to, rotated in or removed from an item frame.	Yes	No
Something being teleported by an end gateway.	Yes	No
An item being inserted to or removed from a flower pot.	Yes	Yes
The shape or rotation of walls, fences, iron bars, glass panes, stairs, tripwire, redstone, vines, mushroom blocks, mushroom stem, fire, all type of rails, glow lichen, sculk vein, pointed dripstone, or chorus plant changing.	Yes	Yes
The top block state of the walls changing.	N/A	Yes
A melon/pumpkin creates from a melon stem/pumpkin stem.	N/A	Yes
The stem of a melon or pumpkin attaching or detaching.	N/A	Yes
Kelp/weeping vines/twisting vines/cave vines turning into a kelp/weeping vines/twisting vines/cave vines plant or vice versa.	N/A	Yes
The berries block state of the cave vines (plant) changing.	N/A	Yes
A campfire being lit or extinguished.	N/A	Yes
Food being cooked or popping out of a campfire.	Yes	No
A hay bale being placed or removed below a campfire.	N/A	Yes
Glowstone being added into a respawn anchor.	No	Yes
A respawn anchor being used.	N/A	Yes
A lodestone being used.	No	No
Oxidation level of unwaxed copper or cut copper block, slab or stairs changing.	N/A	Yes
A copper or cut copper block, slab or stairs being waxed or unwaxed.	N/A	Yes
The tilt block state of a big dripleaf changing.	N/A	Yes
A big dripleaf turning into a big dripleaf stem.	N/A	Yes
Grass/fern/seagrass turning into tall grass/large fern/tall seagrass after bone meal is used on it.	N/A	Yes
Cactus, sugar cane, bamboo, bamboo shoot, vine, weeping vine, twisting vine, kelp, cave vine, pointed dripstone or chorus flower growing.	N/A	Yes
Chorus flower growing or leaving a chorus plant behind and causing a block update to that.	N/A	Yes
An amethyst cluster growing.	N/A	Yes
A bamboo shoot turning into bamboo.	N/A	Yes
The leaves block state of bamboo changing.	Yes	Yes
Mushroom spreading.	N/A	Yes
1-block-tall flowers spreading after bone meal is used on one.‌[Bedrock Edition only]	N/A	No
Glow lichen spreading after bone meal is used on one.	N/A	Yes
Moss blocks spreading after bone meal is used on one.	N/A	Yes
A big dripleaf growing after bone meal is used on it.	N/A	Yes
A small dripleaf turning into a big dripleaf after bone meal is used on it.	N/A	Yes
Hanging roots being created underneath rooted dirt after bone meal is used on it.	Yes	Yes
A hanging mangrove propagule being created underneath mangrove leaves after bone meal is used on it.	N/A	Yes
The number of sea pickle(s) changing after bone meal is used on a coral block.	N/A	Yes
A sea pickle being created after bone meal is used on a coral block.	N/A	Yes
Using bone meal on pink petals that the block state flower_amount is not 4.	N/A	Yes
N/A	Yes
A sapling or a propagule turning into a tree.	N/A	Yes
A mushroom turning into a huge mushroom after bone meal is used on it.	N/A	Yes
An azalea turning into a azalea tree after bone meal is used on it.	N/A	Yes
A fungi turning into a huge fungi after bone meal is used on it.	N/A	Yes
A grass block turning into dirt when a sapling grows into a tree on that grass block.	N/A	Yes
N/A	Yes
A grass block/dirt or any other blocks turning into rooted dirt by when an azalea or a flowering azalea grows on that grass block/dirt.	N/A	Yes
Mud turning into muddy mangrove roots when a mangrove tree grows.	N/A	Yes
A block that has sculk_replaceable tag turning into sculk by sculk catalyst.	N/A	Yes
A sculk vein/Sculk veins being created by sculk catalyst.	N/A	Yes
The shape of sculk vein(s) changing by sculk catalyst.	N/A	Yes
A sculk sensor or a sculk shrieker being created by sculk catalyst.	N/A	N/A
A bell ringing.	Yes	No
The honey-level of a bee nest or a beehive increasing.	N/A	Yes
The honey being collected from a bee nest or a beehive using shears or a glass bottle.	N/A	Yes
A candle being added into a candle.	Yes	Yes
A candle being added into a cake.	Yes	Yes
A candle or candle cake being lit or extinguished.	N/A	Yes
Dirt/coarse dirt/rooted dirt turning into mud through the use of a water bottle.	N/A	Yes
Mud turning into clay through the use of pointed dripstone.	N/A	Yes
A book being add or remove from a chiseled bookshelf by player, hopper, minecart with hopper, or dropper.	N/A	Yes
The dusted block state of a suspicious block changing.	N/A	Yes
A suspicious block turning into sand or gravel.	N/A	Yes
All other block/block state changes.	Yes	Yes

Note blocks[]

Placing the observer beneath the note blocks can generate thumping bass drum beats.

Sounds[]

Java Edition:.

Sound	Subtitles	Source	Description	Resource location	Translation key	Volume	Pitch	Attenuation distance
	Block broken	Blocks	Once the block has broken	block.stone.break	subtitles.block.generic.break	1.0	0.8	16
Block placed	Blocks	When the block is placed	block.stone.place	subtitles.block.generic.place	1.0	0.8	16
	Block breaking	Blocks	While the block is in the process of being broken	block.stone.hit	subtitles.block.generic.hit	0.25	0.5	16
Footsteps	Entity-Dependent	Walking on the block	block.stone.step	subtitles.block.generic.footsteps	0.15	1.0	16

Bedrock Edition:.

Sound	Source	Description	Resource location	Volume	Pitch
	Blocks	Once the block has broken	dig.stone	1.0	1.1-1.2
Blocks	When the block is placed	use.stone	1.0	1.2-1.25
	Blocks	While the block is in the process of being broken	hit.stone	0.3	0.75
Players	Falling on the block with fall damage	fall.stone	0.4	1.0
Players	Walking on the block	step.stone	0.35	1.0
	Players	Jumping from the block	jump.stone	0.12	1.0
Players	Falling on the block without fall damage	land.stone	0.22	1.0

Data values[]

ID[]

Java Edition:.

Name	Identifier	Form	Translation key
Observer	observer	Block & Item	block.minecraft.observer

Bedrock Edition:.

Block states[]

Java Edition:.

Name	Default value	Allowed values	Description
facing	south	down east north south up west	The direction the observer is observing. The same direction the player faces when placing the block.
powered	false	false true	True while the observer is observing a change and emitting a pulse.

Bedrock Edition:.

Name	Metadata Bits	Default value	Allowed values	Values for Metadata Bits	Description
facing_direction	0x1 0x2 0x4	0	0 1 2 3 4 5	0 1 2 3 4 5	The direction the observer is observing. 0: Observer facing down 1: Observer facing up 2: Observer facing north 3: Observer facing south 4: Observer facing west 5: Observer facing east
powered_bit	0x8	false	false true	0 1	True while the observer is observing a change and emitting a pulse.

History[]

Java Edition
November 24, 2012	When announcing the upcoming 1.5 Redstone Update, Jeb mentions that changes to redstone logic may break existing BUD functionality, and therefore that block update detection may need to be implemented into the game in a more permanent, intentional form, rather than as a behavioral quirk.
1.11	16w39a	Added observers.
16w43a	The model of observers has now been changed. The rotation of the “arrow” texture has now been fixed so it points in the correct direction.
General redstone mechanics for observers now work as they did before 16w42a, with the exception of the change named below.
Observers now output strong power like in 16w39a, except that they, as well as redstone repeaters and redstone comparators, no longer provide block updates to transparent blocks or air.
16w44a	The observer block update changes relating to redstone from 16w42a and 16w43a have now been fully reverted.
pre1	The front and top texture of observers have now been changed.
The redstone output side of observers now blinks red when it outputs power.
1.13	17w47a	Prior to The Flattening, this block’s numeral ID was 218.
Due to The Flattening, observers can now detect all block state changes, e.g. the changes in the shape of fences and redstone dust.
pre4	Observers no longer produce a pulse when placed by hand.
20w14a	Observers now correctly detect when the status of the fence changes.
Pre-release 3	The back texture of activated observers has been changed.
1.17	21w13a	Observers now correctly detect when a grass block changes to dirt if a tree grows on top.
Pocket Edition Alpha
build 1	Added observer blocks.
v0.15.3	Observers are now placed like a piston and not a log.
Bedrock Edition
1.2.0	beta 1.2.0.2	The front and top texture of observers have now been changed.
Observer blocks can now detect many more block changes.
The strength of the redstone pulse outputted by observer blocks has now been increased.
Observers no longer pulse twice when observing a retracting piston.
Opening and closing the command block screen no longer activates an observer block.
1.10.0	beta 1.10.0.3	The textures of observers has now been changed.
1.16.0	beta 1.15.0.53	Observers no longer emit a pulse when they are first placed.
1.16.100	beta 1.16.100.55	Observers no longer get stuck in an active state when moved by pistons.
Legacy Console Edition
New Nintendo 3DS Edition
0.1.0	Added observers.

Issues[]

The “Observer” conundrum is being diligently tracked on the bug tracker. Kindly submit your concerns there.

Trivia[]

Gallery[]

Development image of an observer from Jeb.

The first image released of the new observer texture for Java Edition.

See also[]

Block update detector tutorial

Redstone Comparator.

References[]

External Links[]

Minecraft’s Block of the Week: Observer – November 10, 2017 on Minecraft.Net

Nguồn tham khảo: 1