Minecraft Wiki
This article is about the block that detects block updates. For the redstone mechanism, see block update detector.
Observer JE4 BE3.png
Observer (back) JE2.gif

Yes (64)


Blast resistance










Catches fire from lava


An observer is a block that emits a redstone signal when the block or fluid it faces experiences a change.



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

Block Observer
Hardness 3.5
Breaking time[A]
Default 17.5
Wooden 2.65
Stone 1.35
Iron 0.9
Diamond 0.7
Netherite 0.6
Golden 0.45
  1. Times are for unenchanted tools as wielded by players with no status effects, measured in seconds. For more information, see Breaking § Speed.


Ingredients Crafting recipe
Cobblestone +
Redstone Dust +
Nether Quartz


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 pulse.


In Java Edition, an observer detects changes in its target's block states, or the breaking or placing of a block (i.e. changes in its block state, but not its block entity data). This means that changes like the age of crops can be detected because they are part of the block states.

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.

Though they block light, observers behave as transparent blocks in one sense: they cannot be powered by an external power source, nor power themselves with their own output.

Because observers in Java Edition detect changes in the block state, and not block updates, they can detect a wider range of phenomena than a block update detector (BUD) circuit in Java Edition can detect (as some block state changes don't cause block updates). Observers in Bedrock Edition do detect block updates but not block state changes, and so they detect the exact same things that any other BUD would detect in that edition.


Jigsaw Block (top texture) JE2 BE2.png
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You can help by expanding it.
Detected in
Kind of block update Bedrock Edition Java Edition
Detect activation of spawner block No No
Changes to the block states of fire that signifies flammable surfaces surrounding fire No Yes
Opening and closing chests and ender chests No No
Opening and closing shulker boxes No Yes
Opening and closing barrels Yes Yes
Changes to inventory of any blocks that comparators measure as containers No No
Activating / deactivating a beacon Yes No
Success of a command block No No
Activation / deactivation of a hopper (Turning the hopper on/off) Yes Yes
Dry farmland changing among its six dry-looking hydration stages No Yes
Farmland going between dry and humid Yes Yes
Activation / deactivation of a dropper or dispenser Yes Yes
Activation / deactivation of redstone ore Yes Yes
Spread of grass to dirt, or decay of grass into dirt Yes Yes
Aging of saplings, sugar cane or fire Yes Yes
Moving potions to / from a brewing stand Yes Yes
Activation / deactivation of a dragon head Yes No
Placing / removing an item frame, adding / rotating / removing an item in an item frame Yes No
Teleporting something by the end gateway Yes No
Adding / removing contents from a flower pot Yes Yes
Locking / unlocking and changing delay of a redstone repeater Yes Yes
Changes in the shape of walls, fences, iron bars, glass panes, stairs, tripwire, redstone, vines, melon stem[1] or pumpkin stem[1] Yes Yes
A grass, mycelium, or podzol block becoming snowy or not snowy Yes Yes
Playing a note block No Yes
changing the block under a note block No Yes
Forced growth of sugar cane by bone meal Yes No
Cooking food or food popping out Yes No
Placing / removing a hay bale under a campfire N/A Yes
Door is opened or closed Yes Yes
Tripwire is intersected, even if not attached to a hook Yes[2] Yes
All other block / block state changes Yes Yes
Water/Lava level changes Yes Yes
Forced growth of bamboo (bamboo shot to thin or thick leafless bamboo) Yes Yes
Forced growth of bamboo (leaf state change) Yes Yes

Note Blocks[]

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


Java Edition:

SoundSubtitlesSourceDescriptionResource locationTranslation keyVolumePitchAttenuation
Block brokenBlocksOnce the block has brokenblock.stone.breaksubtitles.block.generic.break1.00.816
None[sound 1]BlocksFalling on the block with fall damageblock.stone.fallNone[sound 1]0.50.7516
Block breakingBlocksWhile the block is in the process of being brokenblock.stone.hitsubtitles.block.generic.hit0.250.516
Block placedBlocksWhen the block is placedblock.stone.placesubtitles.block.generic.place1.00.816
FootstepsBlocksWalking on the blockblock.stone.stepsubtitles.block.generic.footsteps0.151.016
  1. a b MC-177082

Bedrock Edition:

SoundSourceDescriptionResource locationVolumePitch
BlocksOnce the block has brokendig.stone1.00.8
BlocksFalling on the block with fall damagefall.stone0.41.0
BlocksWhile the block is in the process of being brokenhit.stone0.370.5
?BlocksJumping from the blockjump.stone0.121.0
?BlocksFalling on the block without fall damageland.stone0.221.0
BlocksWalking on the blockstep.stone0.31.0
BlocksWhen the block is placeduse.stone1.00.8

Data values[]


Java Edition:

NameIdentifierFormTranslation key
ObserverobserverBlock & Itemblock.minecraft.observer

Bedrock Edition:

NameIdentifierNumeric ID FormItem ID[i 1]Translation key
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 with the block.

Block states[]

See also: Block states

Java Edition:

Name Default value Allowed values Description
The direction the observer is observing. The same direction the player faces when placing the block.
True while the observer is observing a change and emitting a pulse.

Bedrock Edition:

NameMetadata Bits Default value Allowed valuesValues for
Metadata Bits
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
True while the observer is observing a change and emitting a pulse.


Java Edition
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.
1.1116w39aObserver JE1.png 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 lasted 1 game tick (0.5 redstone ticks) 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 that observers are essentially instant.
Observers are placed with the observing, or input, side facing the player.
16w41aObservers now emit 4 game tick (2 redstone ticks) pulses.[3]
The signal strength of observers has now been changed to 15.[4][5]
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.[6]
Observers are now placed with the output facing the player.[7][8]
A bug where observers would redirect redstone dust from all 4 directions has now been fixed.[9] (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.[10] 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.[11]
16w43aObserver JE2.png 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.[12]
Observers have now been changed to emit a 2 game tick (1 redstone tick) pulse when activated.[13]
Observers no longer output power instantly.[14]
pre1Observer JE3.png The front and top texture of observers have now been changed.
The redstone output side of observers now blinks red when it outputs power.
1.1317w47aPrior 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.
pre4Observers no longer produce a pulse when placed by hand.
1.1418w43aObserver JE4 BE3.png Observer (back) JE1 BE1.gif The textures of observers has now been changed. The top face is intentionally based on the old, pre-Texture Update top texture of furnace.[15]
1.1620w10aObservers can now support ladders and tripwire hooks.[16]
20w14aObservers now correctly detect when the status of the fence changes.
Pre-release 3Observer (back) JE2.gif 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.
Pocket Edition Alpha
v0.15.0May 2, 2016Jeb tweeted that Daniel Wustenhoff is a working on a BUD block.[17]
Observer (front texture) pBE20160502.png Tommaso Checchi tweeted his "rejected graphics" for the observer block.[18]
build 1Observer BE1.png Added observer blocks.
v0.15.3Observers are now placed like a piston and not a log.
Bedrock Edition
1.2.0beta BE2.png 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 JE4 BE3.png The textures of observers has now been changed.
1.16.0beta no longer emit a pulse when they are first placed.
1.16.100beta no longer get stuck in an active state when moved by pistons.
Legacy Console Edition
TU54CU44 1.52 Patch 241.0.4Observer JE3.png Added observers.
1.90 Observer JE4 BE3.png The textures of observers has now been changed.
New Nintendo 3DS Edition
0.1.0Observer BE1.png Added observers.


Issues relating to "Observer" are maintained on the bug tracker. Report issues there.


  • 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.[18][19]


See also[]


  1. a b Melon or pumpkin stems that become attached to the melon or pumpkin are detected in Java Edition, and Bedrock Edition.
  2. Includes firework rockets, falling block entities, fishing hooks, entities (ie. fireballs, lama spit, evoker fangs etc.) and all throwable projectiles other than splash/lingering potions and enderpearls.
  3. MC-107410
  4. MC-107783
  5. MCPE-17439
  6. MC-108696
  7. MC-107934
  8. MCPE-17321
  9. MC-107795
  10. MC-107730
  11. MC-108897
  12. MC-107760
  13. MC-108697
  14. MC-107623
  15. MC-199231
  16. MC-146824
  17. "Hype train! @darngeek is working on a device that acts as a proper BUD block in MC:PE (PC eventually), currently called "Observer""@jeb_ on Twitter, May 2, 2016
  18. a b "Here's my rejected graphics for the Observer, because @darngeek has no artistic sensibility"@_tomcc on Twitter, May 2, 2016
  19. "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_ on Twitter