Tutorials/Hopper

The hopper is a useful device for controlling/counting/sorting items.

Day counter
This is a very simple machine for counting days. Every time it becomes day, the dispenser is activated and shoots an item into the chest, but you have to be nearby for this to activate, making this fairly useless.

Item counter
A mechanism that outputs short redstone signal for every item that goes through the dropper. The mechanism slows down the items moving through the dropper and the hopper above to make the outputs comfortable to use for counting mechanisms. The output of this counter can be used in any counting mechanism and can be counted using the scoreboard command in a command block. It is possible to change the outputs timing by replacing the bottom comparator with repeater (to make it slower) or redstone dust (to make it faster). Size: 1×4×5 blocks.

This mechanism made by Xbxp.

Introduction
Most item sorters work using hoppers. More specifically, a hopper with all five slots occupied by, for example, redstone, will only be able to collect redstone, because there is nowhere for any other items to go.

Connecting the hopper to a comparator will allow the sorter to measure the contents of the hopper. All five slots MUST remain occupied by the material you are sorting for, otherwise other items will be able to pass through. The easiest way to ensure this is to measure for a 2-strength signal from the comparator, which corresponds to 22 items inside - 18 inside the leftmost slot and 1 each in the other four slots (hoppers lose items in the leftmost slot first). You can also sacrifice an item that you will never sort for, like sticks, 18 inside the rightmost slot, 1 each in the other three slots, and the material that you are sorting for, in the leftmost slot. Alternatively, you can use an item that stacks to 16 (like snowballs). Place a stack of the item to be sorted in the first slot of the hopper. Then, place two snowballs in the second slot and one in each of the remaining slots.

If the output double chest fills up, though, the above design will break adjacent cells due to the signal from the hopper exceeding 2. This alternative design avoids that. The upper hopper here will contain 41 of the item being sorted in one slot, with the other four slots having one each of some item that stacks to 64 and will never go through the sorter (an arbitrary item renamed in an anvil may be used for this purpose).

Components
There are two components to an item sorter: the item channel and the sorting component(s). Here is an analogy to clarify this: the item channel is like a river, and the sorting components can be imagined as nets that only catch certain items. The river ends in a dump (the junk chest).

The item channel is simply a path that items travel through. It can be a horizontal chain of hoppers, or a water channel. Hoppers underneath the hopper chain or water channel act as the "net" and will extract items.

The sorting components are composed of hoppers. To enable deposition and extraction to be independently toggled, two hoppers must be used: one on top of the other, and the top one pointing sideways. The top hopper should be connected to the comparator, which will power the bottom hopper (which takes items out of the top hopper)

Filters for non-stackable items
A variant of sorters is a filter for non-stackable items. These can not be separated using the layout described above, because any individual item would completely fill a slot in a hopper. Instead, this filter operates on empty hoppers and detects different strengths of redstone signals, as stackable or non-stackable items pass through the input hopper. Stackable items (both stackable to 16 and to 64) generate only signal strength 1 in the redstone comparator, while non-stackable items generate signal strength 3, which turns off the redstone torch and unlocks the lower hopper.

The upper hopper must face sideways into another container and can either pull from a container above or be fed from a hopper at any of the three available sides. (Just make sure you don't feed it from above with a hopper pointing downwards into it.) It will hole the item passing through just long enough to examine its "stackability" and allow the lower hopper to pull it out if it is not stackable, before pushing it into the container for stackable items, usually another hopper or chest.

The lower hopper is powered by default so it won't pull items from the upper hopper. It can face in any direction (down or any of the three available sides) and pushes non-stackable items into a container there, usually a chest or another hopper. Going from here, you can apply more specialized filtering methods to further break down the types of items. For example, potions and water bottles can be pushed into the side of a brewing stand and pulled out immediately by a hopper below it to separate them from other kinds of non-stackable items. Note that the item stream needs to be slowed down in order to filter potions reliably.

Auto Smelter/Cooker
Ores and cookable items can be automatically smelted while you're away.

Things you want to be cooked/smelted go into the top chest, Fuel into the lower one. The hopper can put in fuel not only from the side of the furnace but also from the front or behind. The product collects in the bottom hopper or is then redirected into another hopper or another chest.

Note that this method forfeits the XP earned from smelting things. [new with 1.13] Experience will get saved in the furnace until a player picks an item manually.

Hopper Clock
Connect 4 hoppers in a circle (create one pointing at nothing, point a 2nd one at it while crouching, destroy the 1st and use the 2nd as the start of your circle since it's the 1st one pointing the right direction). Put any item that doesn't stack (a wooden axe for example) into any one of the hoppers. Attach a comparator to any one of the hoppers. It will give a signal every time the item goes through that hopper. If you want it to activate more often make a 2 hopper clock. If you want to make it activate less often, place more hoppers.

Slow Clock
Connect two hoppers (let's call them hopper A and B) with their outputs facing each other. Measure their outputs with comparators (comparator A and B). Connect the comparators' outputs to repeaters (repeater A and B), add repeaters perpendicularly to make them lockable (lock A and B). Connect the output of repeater A to hopper B and lock B and the output of repeater B to hopper A and lock A.

To start the clock, throw items into one of the hoppers. The speed of the clock will depend on the amount of items circulating in the system, with the longest duration being 128 seconds in case of 5 stacks of 64 items.

Silo
Sometimes we need a storage way larger than just a single large chest. What we need is a single output container which will be automatically filled up with contents of a large set of other containers preferably hidden behind a wall or a ceiling. We call such system a silo or a mass storage.

The basic form
This is a basic form of silo with 3 large chests. It is 3 blocks wide, 5 blocks high, and is tileable. The actual input of the system is the hopper below "I" so you can push items into it from the side not only from above. The bottommost hopper can also be replaced with a hopper facing any direction, feeding into another hopper.

If you want to use a chest for the output container, it may be advisable to use a trapped chest rather than a normal one. This way item refilling gets suspended while you are accessing the chest so you can return items in case you took more items than you need.

Extended forms
Its true power comes from the extendability. Here are some examples of extended forms. All of these are still tileable.

de::technik:Sortiermaschine