Minecraft Pocket Edition - The ultimate redstone guide (Advanced devices)
Repeat after me
In Minecraft Pocket Edition 0.14, we got a pair of redstone tools that dramatically increase the scale and complexity of the contraptions you'll be able to build.
Repeaters extend the reach of a redstone trail and add delays to the signal. Comparators increase a redstone trail's signal based on the number of items in a container.
Below you'll find out all you need to know about using these advanced devices.Repeaters
Repeaters are used to boost the distance that a redstone signal will travel, and are made on a crafting table using three stone blocks, two redstone torches, and a chunk of redstone dust.
Place a repeater next to a powered redstone trail, and this will reset the signal strength back to full blast.
In the image above, the redstone lamps are too far away from the power source (the redstone torch) to light up, but the repeater resets the signal (to 15).
While you can use these to make a redstone signal travel infinitely far, it's worth mentioning that a repeater adds a delay to the circuit.
By default, the circuit will linger on the repeater for about 0.1 seconds before moving on. But if you edit the repeater (by using it, causing the two torches to move further apart) you can boost this delay to about half a second.
Repeaters are also handy (or annoying - depending on your construction) in that they will only accept signals in one direction, and not from the side (like normal trails of redstone).
This can be used to only allow certain signals and build redstone circuits in small, cramped environments.
More advanced builders will want to know about locking repeaters.
A repeater with a powered repeater going into its side (as shown above) will become locked - shown with a bedrock handle. This makes it deactivated, and is used for some very complex contraptions.Comparators
Redstone comparators are built from three stone blocks, three redstone torches, and a rare piece of Nether quartz. This block can do all sorts.
Place a comparator on the side of a container (like a chest, furnace, brewing standing, or hopper) and the output signal will be dependent on the number of objects and stacks in that container. Above, an almost empty chest can only power one lamp...
But a practically full chest can send the signal much further.
Other objects that can be measured using the comparator include the cauldron (signal depends on how much water it's holding), and a cake (how much has been eaten). You can put the comparator in the middle of a circuit, too.
Comparators can also compare signal strength, if the red light on the front is turned off.
It will compare a redstone signal going into its rear input (the side with two redstone torches) with a signal heading into either of the side inputs (the sides with no torches).
If they're different, as above, no power will be sent to the front input (the side with the red light).
If they're the same, as above, then the signal will pass through.
The comparator can also be used to subtract signal from a redstone circuit. To start, tap the comparator to turn the red light on, and enter subtraction mode.
In this mode, the signal strength that is piped into the side of the comparator will be subtracted from the signal strength that is sent into the rear.
In this example, we've used the comparator to remove signal strength, and stop the redstone getting to - and powering on - the lamp.