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VOOZH | about |
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VOOZH | about |
This article covers types of circuits with insufficient content to justify their own articles.
An ABBA circuit has one input and multiple outputs. When the input turns on, the outputs turn on in order (e.g., A then B), but when the input turns off, the outputs turn off in reverse order (e.g., B then A).
The timing of the output activation and deactivation can be changed by adjusting the delay on the repeaters.
All of these designs can be extended indefinitely.
Earliest Known Publication: 5 July 2011 (basic concept),[1] 20 June 2012 (Floor ABBA),[2] and 18 July 2012 (Ceiling ABBA).[3]
Schematic Gallery: ABBA Circuit
The block update detector switch, or simply BUD, detects any time an adjacent block receives an update. An update is anything that changes that block's state: block placed, destroyed, door opened, repeater delay changed, cake eaten, grass growing, snow falling, furnace used (or turns off), and so on (chests opened and crafting tables used do not cause updates, sleeping in a bed does). When a block is updated, all adjacent blocks are also eligible for an update, and this can be used to produce a redstone signal or for other purposes.
BUDs have been used for all kinds of things, from traps to detecting daylight to locking mechanisms on hidden doors.
Current BUD switches take advantage of a quirk where pistons can receive power, but not updates, from blocks adjacent to the space the piston head occupies when extended. That is: blocks adjacent to the extended state and not adjacent to the retracted state provide power to extend the piston, but as they are not adjacent to the retracted state do not cause the piston to update when that power state changes.
There are many models of auto resetting BUDs. This is done by having the firing of the BUD switch somehow cause the BUD switch to restore the pre-fired state often when fired it cuts the power to the piston, allowing it to retract. This is done either by extra circuitry or, as in the example below, by the properties of blocks themselves.
Version 1.11 introduced the observer block, which sends a one-redstone-tick signal when the block it is facing is updated. However, many designs using BUDs still incorporate older piston variations.
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A multiplex circuit transmits multiple signals on a single transmission line by using a control line to choose which signal should be transmitted or received. The control line may be either clocked, to transmit the signals sequentially, or selection, to simply choose which signal to transmit. The control line(s) can also be substituted with two synchronized pulse generating clocks. Then only one line is necessary. However, they have to stay synchronized for the transmission to be correct. This can be done using a daylight detector.
A multiplex circuit may consist of a multiplexer, a demultiplexer, or both.
A multiplexer (a.k.a. "mux") is a device that selects one of two or more inputs and outputs the selected input. This multiplexer can be chained together, allowing for multiple bit multiplexing.
For these designs, the inputs are labeled A and B. C is the "control" input: whether A or B passes through depends on whether C is powered or not.
Schematic Gallery: Multiplexer
AKA "demultiplexer" or "DEMUX".
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The demultiplexer is the reverse of the multiplexer. It allows you to have one input be sent to either of one of two or more different outputs. Here is a schematic of a demultiplexer with 4 outputs. 'I' represents the input, 'S' represents the selectors and 'f' the outputs. The two selector wires, holding a two digit binary number (2 wires = 2 digits), are passed to a decoder. If the input wire is on, then the output wire of the demultiplexer corresponding to the output of the decoder turns on. For example, if the input is on and the binary number 10b is passed onto the select wires (S0=on,S1=off. Start counting at zero!), then the decoder turns on the third wire (10 in binary is two, but because we start count at zero it becomes the third). An AND operation is performed between the input wire of the demultiplexer and each of the outputs of the decoder. As stated earlier, because both the input wire and only the 3rd output of the decoder is on, only the third output of the whole demultiplexer is on. Demultiplexers are used as decoders with the option to have ALL outputs turned off (done by turning off the input wire). The two schematics on this page are those of a 2 bit demultiplexer. A demultiplexer is not a relay. A relay is an old electronic component that was replaced by transistors in the 70s. Even though a 1-pole relay is the same as a 2 bit demultiplexer, a more complex demultiplexer would be made of many relays (and in the current century of transistors). The closest thing in Minecraft resembling a relay or transistor is the Redstone torch.
A random number generator (aka RNG, or "randomizer") is a circuit that can generate numbers with no recognizable pattern.
The RNGs below depend on the stack maximums of the items they push:
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Analog 2-RNG
The dropper contains one stackable item and one non-stackable item.
👁 Invicon Stick.png: Inventory sprite for Stick in Minecraft as shown in-game linking to Stick with description: Stick→
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Analog 3-RNG
The dropper contains one 64-stackable item, one 16-stackable item, and one non-stackable item.
👁 Invicon Stick.png: Inventory sprite for Stick in Minecraft as shown in-game linking to Stick with description: Stick
👁 Invicon Snowball.png: Inventory sprite for Snowball in Minecraft as shown in-game linking to Snowball with description: Snowball
👁 Invicon Stone Shovel.png: Inventory sprite for Stone Shovel in Minecraft as shown in-game linking to Stone Shovel with description: Stone Shovel When in Main Hand: 3.5 Attack Damage 1 Attack Speed
The hopper contains five 16-stackable items in the far right slot.
👁 Invicon Snowball.png: Inventory sprite for Snowball in Minecraft as shown in-game linking to Snowball with description: SnowballSchematic: Analog 16-RNG
A random selector is a circuit that selects an available output at random.
The random selector (right) depends on the random flight of an item from a dropper.
The input (button) in this random selector turns off the torch, deactivating the piston. It also powers a redstone dust directed into the block, powering the repeater and activating the dropper. The piston then reactivates to push the stuck item (if any). A hopper collects the item and puts it back into the dropper, activating a comparator.
NOTE: The dropper must be facing up. If facing down, the item glitches out of the machine.
Earliest Known Publication: 24 September 2014[8]
An old kind of random selector is the "chicken randomizer", which uses a chicken walking on multiple pressure plates in a containment chamber. For this and other improved randomizers, view the randomizers tutorial.
Another way to construct a random selector is to feed the output of a digital randomizer into a demuxer. You can create a 1-bit digital randomizer from an analog 2-RNG by discarding one of the outputs, and then combine N of them for an N-bit digital randomizer.
A thyristor is a bit like a D flip-flop but has a different functionality. It has two inputs: the "gate" line G and the "anode" line A, and has one output: the "cathode" line K. When triggered by G, the circuit sets its output K to A if A is high, then holds that output state until A goes low. Otherwise K stays low.
Design A is the simplest form of the circuit. The hopper is initially empty so K stays low regardless of whether A is high or low. When G goes high, the item in the dropper moves to the hopper so K goes high as well. The hopper is suspended by A so as long as A is high, the item doesn't go back to the dropper so K is kept high. But there is a downside to this design. When triggered by G while A is low, a 1 tick on-pulse is emitted from K.
Design B is an improved form at the cost of complexity / size / delay. There is an AND gate between G and A so the gate input gets completely discarded when A is low.
Earliest Known Publication: 28 March 2016[9]
Schematic Gallery: Thyristor
This is an automatic item disposer with a start button. Put items in the chest, then push the button behind it. All the items in the chest are thrown into lava via clocked dropper below the chest. While design B is used in this screenshot, design A is fine too because the bogus 1-tick output would activate only the empty disposer.
Hysteresis circuit a.k.a. Schmitt trigger is a circuit that activates the output if input signal power reaches the 'high' threshold, switches it off if power drops to 'low' threshold, and sustains previous state if power remains between the two. Typical use is activation of disposal from storage overflows (which tends to be noisy, so this allows keeping the run-time short), activation of automatic farms to re-fill storage if it's running low, and various storage systems where startup and shutdown are comparably heavy-weight relative to continued operation itself.
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0 – n+1 hysteresis circuit.
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Earliest Known Publication: May 20, 2017[10]
