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.

Unstackable items
A variant of sorters is a filter for non-stackable items. These items 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. The filter is constructed in a way that a signal strength of 1 will not reach the redstone torch, which by default powers the redstone dust dot below it. The dust dot powers the full block next to it, from where the redstone repeater receives its signal and powers the full block next to the middle hopper to lock it.

Note that the middle hopper only gets unlocked long enough to pull in a non-stackable item and potentially push out which ever item it previously contained. Place another hopper below it, as shown in the schematic, to prevent individual items from being held in the middle hopper. That bottom hopper can face in any direction.

Potions and Shulker boxes
These two filters work similarly, in that they consist of a hopper that attempts to push an item into a container, but that container has restrictions on the type of items that can be pushed into it. On a delay, if that push fails, a second hopper will pull the failed item from the input hopper. The potion filter attempts to push items into a brewing stand, which only accepts bottles and brewing ingredients (although, you probably don't want to run ingredients through this filter, because they can't be pulled out), and the shulker box filter attempts to push items into a shulker box, which will not accept other shulker boxes. When the item is rejected by the container, the second hopper becomes unlocked to pull it from the input hopper after a delay of three redstone ticks.

To ensure every item gets an attempt to be pushed into the container, the input rate must be throttled to at most one item every 4 redstone ticks. You could, for example, push items with a dropper on a 4-tick clock.

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