On Java Edition, try the interactive map designed to accompany the tutorials.
In Chapter 1, we built really simple redstone devices with simple power transmission needs: short distances, open spaces, and level ground. But real build environments are usually more complex. You often need to transmit redstone signals over long distances, or in cramped quarters where every block counts.
A little harder than it appears
If you've played around with redstone much, you know this is harder than it seems. There are a lot of little quirks to power transmission that can be really confusing. But after this chapter, you should be able to confidently build simple redstone devices in a wide variety of shapes and sizes. Want a ground-level switch that activates the beacon on top of your ten-story tower? No problem!
Powering Redstone Mechanisms with Wire
There are two ways to power a redstone mechanism with redstone wire:
Route wire into the base of the block
Route wire across the top of the block
Two ways of powering a lamp with wire
Routing power alongside the base won't work.
Redstone wire failing to power a lamp
Identical wiring producing different results
Routing power into (but not across) the top of the block will sometimes work. The details here are complex, and will be covered in later chapters.
Routing power across the top of a block can be a nice way to hide unsightly wiring.
Household lighting powered by wiring on top of the lamps
Power level
Redstone power isn't an all-or-nothing thing; it actually has a level from 0 (off, no power) to 15 (high power).
Power sources usually emit a power level of 15, and redstone mechanisms are activated with any power level greater than zero (sometimes with different effects depending on the exact power level). But those details are for another chapter; our focus now is how power level relates to power transmission.
Wire 15 blocks long lights the lamp; wire 16 blocks long does not.
Whenever redstone power travels from one piece of redstone wire to an adjacent piece of wire, the power level decreases by one. (The power level does not decrease when moving between wire and some other block.) This means redstone wire can carry power at most 15 consecutive blocks; the 16th piece of dust will be unpowered (power level 0). You can see the change visually; higher power levels glow brighter shades of red.
Fortunately, there's a simple solution: a redstone repeater can be used to bring the wire back up to full power. By placing a redstone repeater every 16 blocks, you can transmit power very long distances.
Repeater boosting power level on a wire
Unlike redstone dust, the orientation that you place a redstone repeater is important. It has a back (for power input), and a front (for power output), and if you point it the wrong way it'll block power transmission rather than boost it. The top of a repeater has an arrow indented into its stone surface, indicating which side is the front.
Backwards repeaters won’t transmit power.
VErtical Transmission
So far we've been only been routing power along flat surfaces. But vertical transmission is fairly easy, because redstone wire can travel up and down blocks in a staircase fashion. This is often called, sensibly, a redstone staircase. Wiring can only climb up or down one vertical block at a time -- that's why it has to be a staircase, instead of just a tall pillar.
The staircase can be any shape you want, of course. You can make a long and straight staircase, or a tight spiral staircase.
Straight redstone staircase
Spiral redstone staircase
One thing to be aware of with redstone staircases is that blocks that share edges with the redstone wire will cut the wire so that it stops transmitting power.
Redstone staircase wire cut by neighboring block
Staircases are bulky and take up a lot of space. There are more space-efficient ways of transmitting power vertically, but they rely on more advanced principles, so we'll cover them in later chapters.
Four quirks of redstone wire
Most of our examples so far have used redstone wire in straightforward ways -- transmitting power along a single wire (maybe helped along by repeaters or observers), and often in a straight line. But in practice, you often need wires to make lots of twist and turns, maybe next to other wires in the same area. It's hard to make redstone wiring do what you want if you don't understand all of its quirks.
Quirk 1: Dots of wire behave like crosses of wire
A single powered piece of redstone dust may appear as a dot, as if it's unconnected to anything. In fact, dots of redstone wire behave like crosses -- they are connected to blocks on all sides of them.
In the example shown, a powered dot of redstone dust is powering the three adjacent redstone lamps.
(Note: The reason the redstone wire is powered by the lever, despite the lever being on the other side of the white block, is because the white block is functioning as a transmission component. We'll cover this more in Chapter 3.)
Dot of wire behaving like a cross of wire, lighting all adjacent lamps
Wiring for each device properly separated
Quirk 2: Wire always connects to adjacent wire
Redstone wire will always connect itself to adjacent wire. Sometimes this is what you want, but sometimes not -- for example, if those wires are supposed to be part of separate redstone devices, you'll literally end up with your wires crossed.
Wires crossed
In the second example here, the lamps are each intended to be operated by their own light switch. But because the wires were placed adjacent to each other, they became crossed, and either lever can activate both lamps.
Quirk 3: Wire won't turn to connect to a block
Quirk 2 says that wire always connects to adjacent wire; it'll automatically orient its direction of travel to do so.
But wire won't turn direction to connect to a block (a redstone lamp, for example). To connect redstone wire to a block, you need to route it into the block head-on.
This wiring doesn’t work to activate the left redstone lamp.
Quirk 4: Wire will turn away from a block to connect to adjacent wire
Even if you do route wire into a block head-on, be aware that Quirk 2 will override your wiring layout if there is adjacent wire.
This wiring doesn’t work to activate the middle redstone lamp.
Solving wire routing problems with repeaters
Often you can avoid these routing problems by spacing your wires far enough apart, but sometimes space is too tight for that. In those cases, you can sometimes use repeaters to solve the problems by taking advantage of the fact that repeaters don't have the same quirks.
Using repeaters to avoid crossing different redstone devices’ wires
Using a repeater to insure power goes to a block, instead of connecting to adjacent wire
There are caveats to using repeaters in this way. Remember that repeaters are not just power transmitters, but also signal manipulators. We haven't gotten into what that means yet, but for now, there are two main things to watch out for:
Timing: Redstone repeaters slow down your redstone device. If you're experiencing timing-related issues, the redstone repeaters might be the cause.
Wiring repeater output back to input: You might do this accidentally if your wiring is complex, and it'll probably cause very different behavior than you're expecting.
Repeater feedback loop. Avoid these for now!
Chapter Summary
Powering mechanisms with wire
Redstone mechanisms can be powered by routing wire into the base of the block, or across the top of the block.
Power level
Redstone power has a power level from 0 (off, no power) to 15 (high power).
Whenever redstone power travels from one piece of redstone dust to an adjacent one, the power level decreases by one.
Redstone Repeaters
A redstone repeater can be used to bring a wire back up to full power.
Redstone repeaters have a back (for power input) and a front (for power output).
Vertical transmission
A redstone staircase is a simple way of transmitting power vertically.
Blocks that share edges with redstone wire on a staircase will cut the wire.
Four quirks of redstone wire
Redstone wire has four quirks:
Dots of wire behave like crosses of wire
Wire always connects to adjacent wire
Wire won't turn to connect to a block
Wire will turn away from a block to connect to adjacent wire
Redstone repeaters are one way to manage these quirks.
Redstone Challenge (Companion Map required)
The tower is supposed to light up when you flip the switch next to the door. But it's not working! Can you find and fix the problems?
If you get stuck, the second tower is working, and has the answers posted inside!
Next up: CHARGED Blocks!
You now know what you need to know to transmit power effectively in a lot of different situations. But it's still kind of awkward; our redstone devices are bulkier than they need to be, especially if we add extra blocks to hide the wiring!
In the next chapter, we'll about how charged blocks can be used to transmit power -- and how this can make a big difference in the compactness and aesthetics of our redstone designs.