minecraft-java-editionminecraft-redstone
I'm trying to create an elevator, but I'm stuck at powering them.
I have inputs for each piston, but I can't seem to separate them. It seems that the redstone powers the block beneath it, and all 3 pistons are extended.
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Is there a way to power pistons that are on top of each other?
I am trying to avoid powering of the lower piston in the picture below.
There are actually a large number of different ways you can do this. Perhaps the simplest is using redstone repeaters, like so:
There's also the design proposed by StrixVaria, which uses elevated redstone:
But there are even more ways you can do this. Here are a few:
Take your pick!
The confusion lies in the fact that there are two different types of power a block can emit. These are sometimes referred to as strong and weak power.
Weak power is given to a block under the conditions mentioned in the question, by having wire on top of the block or pointing into it. This will unpower torches, extend pistons, play note blocks and turn on lamps & repeaters.
Strong power is given to a block by having a lever on it, a torch underneath it or a repeater pointing into it. In addition to the abilities weak power has, it will also power redstone dust in an adjacent block.
Best Answer
Pistons are weird. Let me rephrase that: redstone is weird. It never behaves how you would expect it to, consistently. This is especially the case, however, with pistons.
Here's one example:
As you can see, the redstone lamps transfer power in a normal manner (solid block receiving direct power will power the adjacent blocks indirectly). The pistons, on the other hand, behave a little strangely. The first extended piston is powered directly, so it extends. The piston below that one is receiving power indirectly from the block that the redstone is placed on (the lamps behave similarly if you take away the middle lamp). But where the heck is that bottom piston getting power from?
Apparently, pistons can receive power diagonally, or from two blocks above. It was considered a bug for a long time, however, it has since been marked as "Works As Intended". There's a more specific bug report here as well.
Even adding a block in between the redstone and the piston doesn't fix it:
So how do you fix this? Well, that depends on your intended design. If you're going where I think you're going, and going for something similar to a zipper elevator, you actually don't need to worry about this; the zipper design works despite the fact that pistons are activated 2 at a time. Otherwise, you might have to adjust your design, since no combination of blocks and redstone will power just one piston in a vertical tower of pistons. It all depends.