Redstone circuits are a new feature added to Minecraft in the first Alpha update. They allow for advanced, more complicated mechanisms to be created by players. Redstone circuitry is commonly compared to WireMod (a widely-used addon from Garry's Mod).
A combination lock circuit.
How it Works
Signal will only flow 15 squares from its source.
Placing Redstone on a block creates a wire. Every "wired" block has two possible states: 1 (powered) or 0 (unpowered). A wire can be powered by any lever, pressure plate, stone button, or Redstone torch. Placing Redstone on top of a block that is adjacent to a powered block causes the newly wired block to become powered as well. Powered Redstone will always glow red, and will cease to flow after moving 15 blocks from its source. However, the range can be extended without limit by chaining Redstone torches (but will result in a delay).
If all wires adjacent to a torch are unpowered, the torch will provide power to them. However, if a wire connected to it's block is powered by another source, the torch itself will cease to generate power and its flame will go out.
Important Notes
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- Power flows 15 blocks before ending (but can be extended)
- Power sent through multiple torches does not travel instantly, so expect a slight delay when designing
- Circuits that are more than ~300 blocks away from your current position will cease to operate; due to them being on unloaded chunks
Gate Logic
Basic logic gate diagrams
To use a Redstone torch as a logic gate, the source(s) should be connected one block behind the torch itself. To use the torch's state as an output, connect a wire at-level with the torch.
A wire placed directly below the block a torch is on will not connect to the torch. However, another torch placed in the same position will.
Below is a list of some of the basic gates along with example images (a top-down layout overview image can be found to the right). There are many different ways to construct them other than those shown below, so use them as guidelines for creating one to fit your needs.
The NOT gate
NOT gate (inverter)
Also known an inverter. A device that inverts the input. It can also be used as a signal light which is on when no input is detected.
Using two NOT gates can extend your running wire length past the original 15. As of 1.0.2 (the July 6th update), there must be a strip of wire between the two NOT gates.
| In | Out |
|---|---|
| 1 | 0 |
| 0 | 1 |
The OR gate
Three-input OR gate
A device where the output is on when at least one of the inputs are on.
Note that OR gates are simple inversions of NOR gates.
| In 1 | In 2 | Out |
|---|---|---|
| 1 | 1 | 1 |
| 1 | 0 | 1 |
| 0 | 1 | 1 |
| 0 | 0 | 0 |
The AND gate
AND gate
A device where the output is on when both inputs are on.
This is useful in building a locking mechanism for a door, requiring both the activating button and the lock (typically a lever) to be on.
| In 1 | In 2 | Out |
|---|---|---|
| 1 | 1 | 1 |
| 1 | 0 | 0 |
| 0 | 1 | 0 |
| 0 | 0 | 0 |
The NOR gate
NOR gate.
A device where the output is off when at least one of the inputs are on.
These are infrequently used. More commonly-used are the OR gates (above).
| In 1 | In 2 | Out |
|---|---|---|
| 1 | 1 | 0 |
| 1 | 0 | 0 |
| 0 | 1 | 0 |
| 0 | 0 | 1 |
The NAND gate
NAND gate.
A device where the output is off when both inputs are on.
| In 1 | In 2 | Out |
|---|---|---|
| 1 | 1 | 0 |
| 1 | 0 | 1 |
| 0 | 1 | 1 |
| 0 | 0 | 1 |
The XOR/XNOR gate
XOR gate.
Pronounced "exor". A device which activates when the inputs are not equal to each other.
Adding a NOT gate to the end will produce an XNOR gate, which activates when the inputs are equal to each other.
| In 1 | In 2 | Out |
|---|---|---|
| 1 | 1 | 0 |
| 1 | 0 | 1 |
| 0 | 1 | 1 |
| 0 | 0 | 0 |
| In 1 | In 2 | Out |
|---|---|---|
| 1 | 1 | 1 |
| 1 | 0 | 0 |
| 0 | 1 | 0 |
| 0 | 0 | 1 |
RS NOR Latch
RS NOR Latch.
A device where Q will stay on forever after input is received by S. Q can be reset by a signal received by R. This is probably the smallest memory device that is possible to make. Note that ~Q means the opposite of Q, e.g. when Q is on, ~Q is off and vice-versa. This means that in certain cases, you can get rid of a NOT gate by simply picking the ~Q output instead of putting a NOT gate after the Q output.
It is useful for making an alarm system were you for example want a warning light stay turned on after a pressure plate is pressed.
| S | R | Q | ~Q |
|---|---|---|---|
| 1 | 1 | 0 | 0 |
| 1 | 0 | 1 | 0 |
| 0 | 1 | 0 | 1 |
| 0 | 0 | Keep state | Keep state |
RS NAND Latch
RS NAND Latch.
When S and R are both off, Q and -Q are on. When S is on, but R is off, Q will be on. When R is on, but S is off, -Q will be on. When S and R are both on, it does not change Q and -Q. They will be the same as they were before S and R were both turned on.
| S | R | Q | ~Q |
|---|---|---|---|
| 1 | 1 | Keep state | Keep state |
| 1 | 0 | 1 | 0 |
| 0 | 1 | 0 | 1 |
| 0 | 0 | 1 | 1 |
JK Flip-Flop
JK Flip-Flop.
A JK Flip-Flop works a lot like a RS NOR Latch. When the input J is ON and the input K is OFF, the output Q is ON. It will then hold that state until only K or both is ON. When only K is ON the Q is OFF. When both inputs are on they will start a race condition. This means that the output will keep changing until one of the inputs is turned OFF (It doesn't race fast enough to burn out the torches).
NOTE: The illustrated JK Flip-Flop the the right doesn't include the typical inverse Q output. If you want to use the inverse Q then just add an inverter to the Q.
T Flip-Flop
T Flip-Flop.
T Flip-Flops are also know as "toggles". Whenever the input changes from 0(off) to 1(on) the output will toggle its state. A useful way to use T Flip-Flops in Minecraft could for example be a button connected to the input. When you press the button the output toggles (a door opens or closes).
NOTE: The illustrated T Flip-Flop the the right doesn't include the typical inverse Q output. If you want to use the inverse Q then just add an inverter to the Q.
Clock generators
5-clock.
Clock generators are devices where the output is toggling on/off constantly. [1]
The simplest stable clock generator is the 5-clock (shown at the picture to the right). Using this method, 1-clocks and 3-clocks are possible to make but they will "burn out" because of their speed, which makes them unstable. Slower clocks are made by making the chain of inverters longer. It is only possible to make clocks with an odd number of Redstone torches.
Using a different method, a 4-clock can be made ([2]). A 4-clock is the fastest clock which will not overload the torches.
Wire Extender
This System makes it possible to go over the limit of 15 redstone wires at a connection to a door\track\gate\etc.
It is simply 2 "NOT gates" connected to each other. To save resources, you can place one inverter per 15 blocks. If the input is wrong at the other end, just add another inverter.
Example
OFF = IN -> ════╡NOT GATE├▬▬▬┤NOT GATE╞════ OUT -> = OFF
ON = IN -> ▬▬▬▬┤NOT GATE╞═══╡NOT GATE├▬▬▬▬ OUT -> = ON
▬▬ = ON
══ = OFF
"NOT gates" are explained at the top of the page.
Affected Objects
Objects receiving power are affected in the following ways:
- Doors open and close. This is the only method of opening iron doors.
- Tracks
- Tracks will change direction, though always to a turning track.
- TNT will have its charge set. A few seconds of delay should be expected (TNT is not instant).