A lot of things that you need to know if you become a Minecraft player. It is because there are a lot of things that you will find and craft. One of the things that you need to know is about observers. You need to know what observers detect in Minecraft so that you are able to use this block well.
In Minecraft, observers are blocks which can emit a redstone signal when the block or fluid it faces experiences a change. In the game, you can use them to observe the block which is placed against. They are put the same as a piston.
You may wonder, what do observers detect in Minecraft? In Java Edition, an observer detects changes in its block states of the target or the breaking or putting of a block such as changes in its block state, but not its block entity data. It means that changes like the age of crops are able to be detected since they are part of the block states.
In Bedrock Edition, an observer acts as a block update detector and it will detect anything which can cause a block update in that edition. Causes and propagation of block updates are different between Bedrock Edition and Java Edition. So, each of them is able to detect some kinds of changes which cannot be done by others.
When it detects something, the observer will emit a redstone pulse of strong power at level 15 for 2 game ticks. The pulse is able to power redstone dust, a redstone comparator, a redstone repeater or any mechanism component which is located at its opposite end.
If you play in Java Edition, you need to know that the pulse is emitted with a delay of 2 redstone ticks. But, if you play Minecraft in Bedrock Edition, it is supposed to be delayed by 1 tick as well. However, it is actually delayed 2 redstone ticks because of MCPE-15793, a bug causing redstone delays to be incorrect when components are activated by world changes, as opposed to pure redstone components ticking. The timing is also able to be incorrect because of MCPE-73342.
When the observer itself is moved by a piston, it also counts as a block update. If it happens, an observer will emit a pulse after being pushed or pulled, but not beforehand.
Since observers in Java Edition can detect changes in the block state and not block updates, they are able to detect a wider range of phenomena than a block update detector circuit in Java Edition can detect. In Bedrock Edition, observers do detect block updates. However, it is not block state changes. So, they can detect the exact same things that any other BUD will detect in that edition.
Well, that’s the information that we are able to give to you about what observers detect in Minecraft. If you want to know more about observers including about how to craft it, you are able to read the other articles on this site.