Minecraft Wiki

Observer

Revision as of 16:20, 13 April 2025 by SworderExert (talk | contribs) (→‎Limitations)
This article is about the block that detects block updates. For the redstone mechanism, see block update detector.

An observer is a block that emits a quick redstone pulse from its back when the block or fluid directly in front of its "face" experiences a change.

Observer
Observer.png: Infobox image for Observer the block in Minecraft
Observer (back).gif: Infobox image for Observer the block in Minecraft
Invicon Observer.png: Inventory sprite for Observer in Minecraft as shown in-game with description: Observer
Renewable

Yes

Stackable

Yes (64)

Tool

Blast resistance

3

Hardness

3

Luminous

No

Transparent

No

Flammable

No

Catches fire from lava

No

Map color (JE)


  11 STONE 

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        {
            "field": "<span class=\"sprite-file\" style=\"height:32px;width:32px;--vertical-align:middle\">(link to File:Invicon Wooden Pickaxe.png article, displayed as 32x32px|link=Wooden Pickaxe|alt=|class=pixel-image|A wooden pickaxe or better is required to mine this block)</span>",
            "label": "Tool"
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        {
            "field": "3",
            "label": "(link to Explosion#Blast resistance article, displayed as Blast resistance)"
        },
        {
            "field": "3",
            "label": "(link to Breaking#Blocks by hardness article, displayed as Hardness)"
        },
        {
            "field": "No",
            "label": "(link to Light article, displayed as Luminous)"
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        {
            "field": "No",
            "label": "(link to Opacity article, displayed as Transparent)"
        },
        {
            "field": "No",
            "label": "(link to Flammable article, displayed as Flammable)"
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            "field": "No",
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            "label": "(link to Map color article, displayed as Map color) <small>((link to Java Edition article, displayed as ''JE''))</small>"
        }
    ],
    "invimages": [
        "Observer"
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    "images": [
        "Observer.png",
        "Observer (back).gif"
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Obtaining

Breaking

An observer requires a pickaxe to be mined. When mined without a pickaxe, it drops nothing.

Block Observer
Hardness 3
Tool
Breaking time (sec)[A]
Default 15
BlockSprite oak-planks.png: Sprite image for oak-planks in MinecraftWooden 2.25
BlockSprite cobblestone.png: Sprite image for cobblestone in MinecraftStone 1.15
ItemSprite iron-ingot.png: Sprite image for iron-ingot in MinecraftIron 0.75
ItemSprite diamond.png: Sprite image for diamond in MinecraftDiamond 0.6
ItemSprite netherite-ingot.png: Sprite image for netherite-ingot in MinecraftNetherite 0.5
ItemSprite gold-ingot.png: Sprite image for gold-ingot in MinecraftGolden 0.4
Legend
  • incorrect tool, drops nothing
  • correct tool, drops nothing or something other than the block itself
  • correct tool, drops the block itself
  • italicized can be instant mined
  1. ↑ These durations ignore other influential factors (e.g. Mining Fatigue), and are measured in seconds. For more information, see Breaking § Speed.

Crafting

Ingredients [hide]Crafting recipe
Cobblestone +
Redstone Dust +
Nether Quartz
Invicon Cobblestone.png: Inventory sprite for Cobblestone in Minecraft as shown in-game linking to Cobblestone with description: CobblestoneInvicon Cobblestone.png: Inventory sprite for Cobblestone in Minecraft as shown in-game linking to Cobblestone with description: CobblestoneInvicon Cobblestone.png: Inventory sprite for Cobblestone in Minecraft as shown in-game linking to Cobblestone with description: CobblestoneInvicon Redstone Dust.png: Inventory sprite for Redstone Dust in Minecraft as shown in-game linking to Redstone Dust with description: Redstone DustInvicon Redstone Dust.png: Inventory sprite for Redstone Dust in Minecraft as shown in-game linking to Redstone Dust with description: Redstone DustInvicon Nether Quartz.png: Inventory sprite for Nether Quartz in Minecraft as shown in-game linking to Nether Quartz with description: Nether QuartzInvicon Cobblestone.png: Inventory sprite for Cobblestone in Minecraft as shown in-game linking to Cobblestone with description: CobblestoneInvicon Cobblestone.png: Inventory sprite for Cobblestone in Minecraft as shown in-game linking to Cobblestone with description: CobblestoneInvicon Cobblestone.png: Inventory sprite for Cobblestone in Minecraft as shown in-game linking to Cobblestone with description: Cobblestone
Invicon Observer.png: Inventory sprite for Observer in Minecraft as shown in-game with description: Observer

Usage

An observer is placed similarly to a piston. It observes the block that it is placed against. The texture of the detecting side is that of an observing face. As observers can detect the state of other observers, placing two adjacent observers, each watching the other, can make a fast and compact redstone clock. They send out a redstone pulse.

Behavior

In Java Edition, an observer detects shape updates in its target block. This can involve changes in block states, or the breaking or placing of a block. This means that changes like the age of crops can be detected because they are part of the block states. In Java Edition, this makes observers differ from block update detectors in terms of what they can detect.

In Bedrock Edition, an observer acts as a block update detector and detects anything that causes a block update.

The causes and propagation of block updates are different between Java Edition and Bedrock Edition. As a result, each can detect some kinds of changes that the other cannot. See the table below for a comparison.

When it detects something, the observer emits a redstone pulse of strong power at level 15 for 2 game ticks (1 redstone tick). The pulse can power redstone dust, a redstone comparator, a redstone repeater, or any mechanism component located at its opposite end.

In Java Edition, the pulse is emitted with a delay of 1 redstone tick. In Bedrock Edition, it is supposed to be delayed by 1 tick as well but is actually delayed 2 redstone ticks due to MCPE-15793, a bug causing redstone delays to be incorrect when components are activated by world changes (which, in the case of the observer in Bedrock Edition, is the only way it can be activated), as opposed to pure redstone components ticking. Its timing can also be incorrect due to MCPE-73342.

It also counts as a block update when the observer itself is moved by a piston. When this happens, an observer emits a pulse after being pushed or pulled, but not beforehand. This enables them to be used in flying machines.

Observers behave as both opaque and transparent blocks: they block light and allow mob spawning on top, but do not block opening chests below (Java Edition only), do not cut off redstone wire, and cannot conduct redstone power.

Because observers in Java Edition react to shape updates, they can detect some changes that a block update detector (BUD) would be unresponsive to, as opposed to Bedrock Edition where observers detect the exact same updates that any other BUD would detect.

Limitations

Note blocks

The observer can be placed under note blocks to produce bass drum sounds.

Sounds

Java Edition:

[hide]
BlockSprite stone.png: Sprite image for stone in Minecraft stone sound type
SoundSubtitlesSourceDescriptionResource locationTranslation keyVolumePitchAttenuation
distance
​Block brokenBlocksOnce the block has brokenblock.stone.breaksubtitles.block.generic.break​1.00.816
​Block placedBlocksWhen the block is placedblock.stone.placesubtitles.block.generic.place​1.00.816
​Block breakingBlocksWhile the block is in the process of being brokenblock.stone.hitsubtitles.block.generic.hit​0.250.516
​Something falls on a blockEntity-DependentFalling on the block with fall damageblock.stone.fallsubtitles.block.generic.fall​0.50.7516
​FootstepsEntity-DependentWalking on the blockblock.stone.stepsubtitles.block.generic.footsteps​0.151.016

Bedrock Edition:

[hide]
BlockSprite block-of-gold.png: Sprite image for block-of-gold in Minecraft metal sound type
SoundSourceDescriptionResource locationVolumePitch
BlocksOnce the block has brokendig.stone1.01.1-1.2
BlocksWhen the block is placeduse.stone1.01.2-1.25
BlocksWhile the block is in the process of being brokenhit.stone0.30.75
PlayersFalling on the block with fall damagefall.stone0.41.0
PlayersWalking on the blockstep.stone0.351.0
BlocksJumping from the blockjump.stone0.121.0
BlocksFalling on the block without fall damageland.stone0.221.0

Data values

ID

Java Edition:

NameIdentifierForm[hide]Translation key
BlockSprite observer.png: Sprite image for observer in Minecraft ObserverobserverBlock & Itemblock.minecraft.observer

Bedrock Edition:

NameIdentifierNumeric ID FormItem ID[i 1][hide]Translation key
BlockSprite observer.png: Sprite image for observer in Minecraft Observerobserver251Block & Giveable Item[i 2]Identical[i 3]tile.observer.name
  1. ↑ ID of block's direct item form, which is used in savegame files and addons.
  2. ↑ Available with /give command.
  3. ↑ The block's direct item form has the same ID as the block.

Block states

See also: Block states

Java Edition:

Name Default value Allowed values [hide]Description
facingsouthdown
east
north
south
up
west		The direction the observer is observing. The same direction the player faces when placing the block.
poweredfalsefalse
true		True while the observer is observing a change and emitting a pulse.

Bedrock Edition:

NameMetadata Bits Default value Allowed valuesValues for
Metadata Bits		 [hide]Description
minecraft:facing_directionNot Supporteddowndown
east
north
south
up
west		UnsupportedThe direction the observer is observing. The same direction the player faces when placing the block.
powered_bit0x8falsefalse
true		0
1		True while the observer is observing a change and emitting a pulse.


Video

History

November 24, 2012When 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.
May 2, 2016Jeb tweeted that Daniel Wustenhoff is a working on a BUD block.[22]
Tommaso Checchi tweeted his "rejected graphics" for the observer block.[23]
[hide]Java Edition
1.1116w39a Added observers.
Note: the "arrow" texture on the top/bottom of observers is pointing the wrong direction (toward the input, rather than the output).
Observers act as a block update detector.
Observers emit pulses that last 2 game ticks (1 redstone tick) and have a signal strength of 1.
Observers can power blocks (like a redstone repeater).
Observers have no delay between detecting a block update and emitting a pulse, meaning they are instant.
Observers are placed with the observing, or input, side facing the player.
16w41aObservers now emit 4 game tick (2 redstone ticks) pulses.[24]
The signal strength of observers has now been changed to 15.[25][26]
Observers *appear* to no longer strongly power blocks, and now emit only activation power, like a block of redstone (and this may be the intended behavior for this snapshot). However, in reality, they still strongly power blocks, but the blocks adjacent to those blocks aren't given block updates, causing buggy behavior.[27]
Observers are now placed with the output facing the player.[28][29]
A bug where observers would redirect redstone dust from all 4 directions has now been fixed.[30] (They are supposed to redirect dust only from their output side.)
16w42aThe developers have attempted to make observers no longer detect block updates happening to air blocks, in order to make observer behavior more predictable.[31] In the process, they have broken redstone mechanics a bit, so that the block update bug from the previous snapshot now affects redstone repeaters and redstone comparators, too.[32]
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.
16w44aThe observer block update changes relating to redstone from 16w42a and 16w43a have now been fully reverted.
The behavior of observers has now been overhauled/redefined. Observers have now been changed from a block update detector to a block state change detector.
Observers have now been changed to detect when the block it was observing changed, its basic block state changed, or the block was placed/destroyed. (Note that it does not detect changes in the extended block state, e.g. changes that are not saved when the world is unloaded, such as the shape of a fence, or whether or not a repeater is locked.) This change has now made observer behavior much more predictable, as unexpected/invisible block updates would no longer trigger observers.[33]
Observers have now been changed to emit a 2 game tick (1 redstone tick) pulse when activated.[34]
Observers no longer output power instantly.[35]
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.
1.1317w47aDue to The Flattening, observers can now detect all block state changes, e.g. the changes in the shape of fences and redstone dust.
pre4Observers no longer produce a pulse when placed by hand.
1.1418w43a The textures of observers has now been changed.
1.1620w10aObservers can now support ladders and tripwire hooks.[36]
20w14aObservers now correctly detect when the status of the fence changes.
Pre-release 3 The back texture of activated observers has been changed.
1.1721w13aObservers now correctly detect when a grass block changes to dirt if a tree grows on top.
[hide]Pocket Edition Alpha
v0.15.0build 1 Added observer blocks.
v0.15.3Observers are now placed like a piston and not a log.
[hide]Bedrock Edition
1.2.0beta 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.
1.10.0beta 1.10.0.3 The textures of observers has now been changed.
1.16.0beta 1.15.0.53Observers no longer emit a pulse when they are first placed.
1.16.100beta 1.16.100.55Observers no longer get stuck in an active state when moved by pistons.
[hide]Legacy Console Edition
Xbox 360Xbox OnePS3PS4PS VitaWii USwitch
TU54CU441.521.521.52Patch 241.0.4 Added observers.
TU57CU491.571.561.56Patch 271.0.7Observers now register changes to item frames and flower pots.
TU63CU531.671.671.67Patch 321.0.13The red light on the back side of the observer is now lit when the observer is activated.
1.90 The textures of observers has now been changed.
[hide]New Nintendo 3DS Edition
0.1.0 Added observers.

Data history

[hide]Java Edition
1.1317w47aPrior to The Flattening, this block's numeral ID was 218.
[hide]Bedrock Edition
1.20.10Preview 1.20.10.23Now uses the minecraft:facing_direction block state instead of facing_direction.

Issues

Issues relating to "Observer" are maintained on the bug tracker. Issues should be reported and viewed there.

Java Edition

  • MC-256913 – Redstone dust not pointing towards quickly moved observer
  • MC-170288 – TNT transforms into observer
  • MC-191016 – Observers pulsing when using /setblock
  • MC-192330 – Double observer pulse on removing wood from leaf line
  • MC-251340 – Observers incorrectly detect block updates of wall blocks
  • MC-107664 – Some events / actions do not trigger observers
  • MC-107671 – Observers act as transparent blocks with redstone wires
  • MC-133149 – Observers trigger when placed via a structure block
  • MC-136566 – When a piston retracts an active observer and is immediately repowered, it does not extend
  • MC-137127 – Observers do not react to pulsing pistons correctly when they're retracting an observer facing away from it.
  • And 13 other open issues.

Bedrock Edition

  • MCPE-29548 – Relogging can cause observers to emit pulses
  • MCPE-89921 – Observers dont activate redstone dust and repeaters when it is pushed by a sticky piston and that sticky piston gets powered by another observer
  • MCPE-105821 – Observers are inconsistent on chunk borders
  • MCPE-153821 – Observers don't detect sculk shrieker shrieking properly
  • MCPE-30544 – Observer doesn't detect curved rail changing direction
  • MCPE-31580 – Observer's left side texture is upside-down in City Texture Pack
  • MCPE-41074 – Observer not detecting netherwart growing
  • MCPE-46345 – Observers do not detect an entity entering/exiting a bed
  • MCPE-53919 – Observers don't detect changes to Note Blocks
  • MCPE-60920 – Observer's right side texture is upside-down
  • And 12 other open issues.

Trivia

  • The current observer texture was created because Jeb kept confusing the front with the back. He said it was inspired by the "rejected texture" created by Tommaso Checchi.[23][37]

Gallery

Screenshots

  • Development image of an observer from Jeb.

    Development image of an observer from Jeb.

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

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

See also

References

  1. ↑ For example, a button attached to a block, when breaking the block, that button breaks and causes block update that can be detected by observer.
  2. ↑ For example, a mushroom are on light level of 13, according to the Minecraft Wiki, at level 13 and above, mushroom uproots unless on mycelium, podzol, or nylium. When the mushroom is updated, that mushroom breaks and causes a block update that can be detected by observer.
  3. ↑ Another example, a wheat crop uproots at level 0 or below. When updating the wheat, that wheat breaks and causes a block update that can be detected by observer.
  4. ↑ While it's not possible to set this up normally (since the observer has to place on the side of the cactus (because the top and the bottom are already occupied by the fluid and the block that supports the cactus (like sand) relatively), which causes the cactus to break), it's possible to reproduce this using the /fill ~ ~ ~ cactus strict command.[verify]
  5. ↑ For example, places 2 chorus plants on top of an end stone, and when a chorus plant is placed on the side of the bottom one, that "bottom" chorus plant breaks and causes block update, which can be detected by the observer.
  6. ↑ Will be detected without the strict argument, will not with the strict argument.
  7. ↑ MC-107664
  8. ↑ MCPE-130935
  9. ↑ In Java Edition removing an end portal frame block won't destroy the portal.
  10. ↑ In Java Edition the game rule snowAccumulationHeight must be larger than 1.
  11. ↑ When the fluid source block is removed, all of the fluid flowing from the source is removed and causes a block update.
  12. ↑ In Bedrock Edition, rabbits do not eat carrot crops; see MCPE-113321 and MCPE-131980.
  13. ↑ In Bedrock Edition, the death of a coral fan cannot happen under normal circumstances — it happens the next tick after the coral fan is placed, so the observer has already read the placement or water removal update, and coral fans placed using commands are waterlogged — but if lag is used to make the unwaterlogging and death events happen separately, the observer detects both. For coral, the death also happens too fast for the observer to detect it separate from the placement or water removal, but a non-waterlogged coral can be placed using commands. Coral blocks take multiple seconds to die, and removing water next to the coral block does not activate the observer anyway, so they can be detected under normal circumstances.
  14. ↑ This event cannot normally happen, but if commands are used to place a wet sponge in the Nether, the sponge dries when it recieves a random tick.
  15. ↑ The disarmed‌[JE only] or disarmed_bit‌[BE only] block state cannot change without also detaching the tripwire, so this event cannot happen in isolation.
  16. ↑ In Bedrock Edition, observers detect when a sculk shrieker stops shrieking, but not when it starts shrieking.
  17. ↑ In Bedrock Edition, placing a pumpkin or melon next to a corresponding stem does not cause the stem to attach.
  18. ↑ From nothing to small to medium to large and finally to cluster.
  19. ↑ In Bedrock Edition, using bone meal on a coral block does not create sea pickles, due to MCPE-171383.
  20. ↑ Includes short grass, tall grass, 1-block-tall flowers, seagrass, tall seagrass, coral, (wall) coral fan, moss carpet, azalea, flowering azalea, crimson roots, warped roots, fungus, nether sprouts, twisting vine, and pink petals.
  21. ↑ Applies to the block under the sapling and the area around the sapling.
  22. ↑ "Hype train! @darngeek is working on a device that acts as a proper BUD block in MC:PE (PC eventually), currently called "Observer"" – @jeb_ (Jens Bergensten) on X (formerly Twitter), May 2, 2016
  23. ↑ Jump up to: a b "Here's my rejected graphics for the Observer, because @darngeek has no artistic sensibility" – @_tomcc (Tommaso Checchi) on X (formerly Twitter), May 2, 2016
  24. ↑ MC-107410
  25. ↑ MC-107783
  26. ↑ MCPE-17439
  27. ↑ MC-108696
  28. ↑ MC-107934
  29. ↑ MCPE-17321
  30. ↑ MC-107795
  31. ↑ MC-107730
  32. ↑ MC-108897
  33. ↑ MC-107760
  34. ↑ MC-108697
  35. ↑ MC-107623
  36. ↑ MC-146824
  37. ↑ "I kept confusing myself which side was front and back, so here's something inspired by the works of @_tomcc http://i.imgur.com/IK2d8m2.png" – @jeb_ (Jens Bergensten) on X (formerly Twitter), November 7, 2016
  1. ↑ Jump up to: a b When deactivated, the sculk sensor's and the calibrated sculk sensor's "sculk_sensor_phase" block stage is converted from "active"->"cooldown"->"inactive". This means that a deactivating sculk sensor actually triggers an observer twice in a row.

External links

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