Redstone Comparator
minecraft:comparatorThe redstone comparator is a crafted redstone component made from redstone torches, nether quartz, and stone that can compare or subtract two side signals against a rear signal, and also read container fullness or block states like cake bites and lectern pages.
FAQ
What do you need to craft a redstone comparator?
Three redstone torches, one nether quartz block, and three stone blocks arranged in the crafting grid.
What's the difference between comparison and subtraction mode?
Toggling the front torch switches the comparator between comparison mode (outputs the rear signal if it's stronger than both side signals) and subtraction mode (subtracts the strongest side signal from the rear signal).
Can a comparator read how full a chest is?
Yes, it can measure the fullness of chests, hoppers, furnaces, and dozens of other containers, outputting a signal strength from 1 to 15.
How much delay does a comparator add to a signal?
It takes 2 game ticks, or 0.1 seconds, for a signal to pass through a comparator from either the rear or the side inputs.