Tutorials/Hopper

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

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.

Item sorter
Item sorters are type of a redstone mechanism which can be used to filter specific items into chests. The generally work using two hoppers, as shown in the schematic. The topmost hopper (labeled I) is filled up so that it can only accept the item being sorted. The hopper underneath (labeled O) is powered so that it cannot remove items from the top. When enough items fill the top hopper, the bottom hopper O is unpowered so that it can remove the extra items.

Storage
Usually chests are placed sideways to the right of the hoppers below I. The hoppers under O are optional, but they can be used to attach more chests. As hopper O is the only one that needs to be powered, as many hoppers and chest can be added as necessary.

At the end of an item sorter, there is usually a chest to catch any items that didn't get sorted for some reason. This is helpful in case a valuable tool or such is accidentally dropped in. If a chest becomes full, it can also prevent the loss of items of that type. Sometimes large farms storages will use lava instead to prevent a buildup of items should the storage completely fill up.

Overflow protection
When multiple sorters are tiled directly next to each other, it is usually desirable to have overflow protection. In a overflow safe sorter, even if the topmost hopper has filled up due to an "overflow," the redstone signal strength will not be great enough to interfere with adjacent sorters. In the sorter shown, 1 full stack of items and 4 junk items will produce a signal strength of 3. This is just strong enough to unlock the bottom hopper without affecting adjacent hoppers. If the signal strength were to get up to 4 however, the adjacent hoppers would be unlocked causing the whole system to break down.

The first slot of the input hopper should contain the item being sorted out. The other slots should contain items which will go through the system. Named sticks, dirt, and cobblestone are all common 'junk' items used for this purpose. Only one junk item should be placed in each slot. Otherwise, the sorter will not have ensured overflow protection.

It is possible to remove the center column of blocks from the sorter. However, to do so will remove overflow protection. If the input hopper fills up, it will have a signal strength of 3 which will unlock adjacent hoppers.

Item transportation
There are multiple methods which can be used to carry items across the input hopper to potentially be picked up. The two methods most frequently used are hopper lines and item streams.

A hopper line is simply a chain of hoppers all pointing at each other in a continuous line. This requires extra iron and may cause consistent lag on large scale.

Item streams, on the other hand, are made by running water over the hoppers and dropping items into the flow with a dropper. Whenever the stream grows too weak, ice and signs are used to carry items across the breaks. This is a cheaper method, provided Silk Touch has been obtained. However, while items are flowing through the system, it may generate more lag than using hoppers. Additionally, there is a greater chance for items to skip over and not be sorted.

Item filters
Item filters, while similar to item sorters, sort items using unique properties rather than item type and name. They are usually used to sort unstackable items such as armor, shulker boxes, and potions. As item filters do not work with every item type, they may be most useful in combination with item sorters rather than as a standalone.

Unstackable items
An unstackable item filter can be used to separate unstackable items, such as armor, tools, potions, and enchanted books, from stackable item. This can be useful with mob farms where tools will need to be separated from everything else.

When an unstackable item enters input hopper A, it will unlock output hopper B. The unstackable item will then go into hopper B to be sorted elsewhere. If a normal item enters hopper A, hopper B will remain locked and the item can be outputted from hopper A.

The optional hopper C can prevent valuable items such as shulker boxes and diamond armor from being temporarily stuck in the system. When hopper B is locked, there is usually an item left in it. Hopper C, however, can still pull the items from hopper B. In one of the tileable designs, hopper C is locked with hopper B and cannot do this.

Note that these designs are not overflow protected. Should the storage connected to hopper A fill up, items will begin to flow into storage B. An overflow with a tileable design could cause similar issues with adjacent modules.

Potions and shulker boxes
This item filter uses certain containers which restrict the kind of items that can enter them. The two containers which do this are brewing stands and shulker boxes. These allows potions and shulker boxes to be separated from other items. This could be handy to sort potions to a storage or shulker boxes to be unloaded.

With this design, items are inputed through hopper A. Any items which are allowed to enter are outputted through hopper B and items which are restricted through hopper C. If a brewing stand is used, potions will be allowed to enter the stand and go to output B. If a shulker box is used, shulker boxes will be prevented from entering and will go to output C.

This design has a circuit delay of 4 ticks which is slower than the speed of hoppers at 3 ticks. To ensure that every item gets an attempt to be pushed into the container, the input rate must be throttled to at one item per 4 redstone ticks. This could be done with a dropper on a 4 tick clock.

When building, note that the redstone repeater is on 2 tick delay. Hopper C is optional as it is only used to make the design item-safe. If using a brewing stand, blaze powder can be pushed into it but not removed. This usually shouldn't be a problem, however it may be desirable to fill the stand beforehand.

Automatic smelting
To make the smelting process more efficient, it is possible to use hoppers to ensure a furnace is never left empty. In the shown schematic, chest A is for items such as uncooked meat, chest B is for fuel such as coal, and chest C holds the output. Since furnaces can hold fuel without a chest, chest B and its hopper are unnecessary.

Using a system like this greatly speeds up the process of smelting large numbers of items. Should it become necessary to smelt an even larger number however, it is possible to link multiple modules to create what is commonly called a "furnace array." These vary in size and can range from very small to using close to a hundred furnaces.

In Bedrock Edition, using a hopper to remove an item from a furnace will cause any experience gained from smelting items to be lost.

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.

Storage silos
It is sometimes necessary to store items in more than just one chest. Using hoppers, it is possible to store items it hundreds or even thousands of chests. This is usually done with either a connected design or an accessible design.

The connected design should be used when it is necessary to take items from a single output. Any items stored in this silo will funnel down as the bottom chest is emptied. Since the chests are not all easily accessible, this is more helpful in automation rather than use by the player. If it is not necessary to remove a large number of items, it could work, however. Silos like this are commonly used to hold hold fuel, minecarts, and shulker boxes.

The accessible design should be used when the player, not redstone contraptions, will be using the stored items. When the bottom chest is emptied, only items stored in the adjacent hopper can fill it back up. Since the bottom chest is the only one which can be removed from with a hopper, it is impractical to use this for automation. Silos like this are commonly used in combonation with sorting systems.

The accessible design is slightly faster than the connected design since the hoppers are in a vertical line. If an item is still in the top hopper after the one below has grabbed another, it will put the item into the chest. If the upper chests become full, however, the speed will slow down to the normal 2.5 items per second.

These designs are easily expandable to fit storage needs. The expandable design can easily to tiled upwards and to one side, while the connected design can be expanded in all directions. Below are some schematics demonstrating some of these possibilities.

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