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Tutorials/Mob grinder

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Mob grinders are the last part of a mob farm and are used to kill mobs in massive amounts while also collecting all dropped items at a convenient location. They are a mechanism and can be considered a special type of trap.

Mob grinders are sometimes specific to a certain size of the mob. Tall mobs usually refer to tall hostile mobs, namely skeletons, zombies, and creepers, but can also refer to zombie pigmen. Small/short mobs are only 1 block tall and are spiders, pigs, wolves, chickens, cows, sheep, and ocelots.

Squid and ghasts have unique behavior, spawning conditions, and/or size making them difficult to grind. Therefore, they are often omitted when someone says 'all mobs'.

Mob grinders will not produce music discs or rare drops as the mob deaths do not meet the conditions for those items. However, if built in a particular way the conditions can be favorable to induce such situations, but will require the player to impart minimal input in such instances.

Common Styles[edit]

The following are the most common styles of mob grinders. They are efficient and relatively small.

Mob Grinders for Java Edition[edit]

Information icon.svg
This feature is exclusive to Java Edition.

Fall Damage[edit]

A fall damage grinder consists of a mob farm where mobs are spawned and a platform where mobs fall to death. Different methods can be used to make the mob farm, to push the mobs to fall from a lethal height, and also to retrieve the loot from the mobs. It is one of the easiest models of a mob grinder, requiring resources that are easily obtainable. Fall damage is 1♥ for each block of fall distance after the third. Thus, falling 4 blocks causes 1♥ damage, 2♥ damage for 5 blocks, and so forth. Note that zombies have a form of "natural armor" that they spawn with that grants a slight protection bonus. It's only an 8% damage decrease, but it does work against falling and suffocation. No automated method, including the combination of falling and suffocation, can bring a zombie anywhere between 0♥ and 1♥ HP without killing it, so grinding zombies with the fists will be inefficient. Also, if skeletons or zombies spawn with Feather Falling boots, the same issues will take place. A Strength beacon will likely take care of this though.

Lava Retrieval Traps[edit]

A trap made with water and lava (frontview).

Lava tends to destroy drops, but this can be avoided by suspending the end of a lava stream on a ladder or forcing mobs to the termination point of a lava stream. Ladders and signs are considered solid blocks by liquids but empty blocks by mobs or players. Also, consider using water to drown mobs to ensure that no drops will be lost. The player may use a simple 8×8 area with a mob spawner leading to a water drop that mobs can push each other into, making so the drops come out when mobs spawn, and makes lag a non-occurrence.

Cross section. Loot is gathered below the ladder.

The canals from the mob farm send mobs into this final water channel. The mobs are forced into the chest-high lava blade. The same water that drags the mobs into the lava also pushed the drops into a collection point. Combine with a final perpendicular-flow water current to deliver all items to a single tile, on which a wooden pressure plate may be placed and attached to redstone torches or lamps to indicate the availability of items. Alternately, the stream can empty the items into a hopper connected to a chest, (or a further item sorting system) for retrieval at the player's leisure. Endermen do not pick up stone or cobblestone, so the player does not have to worry about them ruining the system of spawning the mobs.

Lava dispenser grinder[edit]

This dispenses lava for a short period of time to the mobs which catch them on fire and "soften" them so the player can kill them with 1 or 2 hits.

Piston Smasher Trap[edit]

Example setup of the Piston Smasher Trap.

This trap consists of a piston that pushes a mob under a sticky piston. The sticky piston simultaneously pushes a block on the mob's head to suffocate it. This setup is connected to a repeater to allow new mobs to enter the smashing area. Water can be used to transport items from the smashing area to a collection point. The trap damages about one heart per second. This setup only works for tall mobs, but the principle can be used for smaller mobs as well.

The downside to this trap is the slow rates of kills, since each mob needs about 10 seconds of suffocation before it dies. This problem can be fixed by having a row of pistons push together at once, suffocating multiple mobs in every smash.

Timing is very important for this trap to work efficiently: For single mob smashes, a loop of at least 30 repeaters set at maximum are needed, giving 12 seconds per loop. With this setup, turn on the loop for a little more than 10 seconds to ensure they die, and have the loop off for the rest, giving 10 second kills and 2 second load times. For a full row of 8 pistons, the load time is approximately 6 seconds, meaning the loop needs to have 40 repeaters giving a 16-second loop. Load time for a stream of 8 blocks long and 2 blocks wide, with pistons on both sides, is about 8 seconds. This amounts to at least 48 repeaters.

Another downside to piston smashers is the inability to handle spiders. The player would need another way to sort out spiders, such as a cactus choke.


Drowning grinders work by sending mobs into a small area without an air pocket. This video tutorial shows step by step how to attach a simple drowning trap to a vertical mob elevator.

This type of trap is advantageous because of the impossibility of losing items to lava/cacti as well as the possibility for compact designs. Zombies cannot drown in water, but will instead convert into drowned. Skeletons are also unable to drown

Item sorting hopper platform[edit]

Build a hopper platform under a mob farm, where mobs will fall to death. Hoppers automatically retrieve the loot and can be connected to chests to store it in several ways.

Fall damage with railroad retrieval system[edit]

The player can make a mob farm in the air and then set a platform area where mobs will fall to death. To retrieve the resulting loot, they can build a railroad system in such a way that they will be automatically retrieving all the loot while being AFK (away from keyboard or screen). Falling mobs will hit the player and could stop the riding, so it's important to have the smashing area covered with powered rail and the curves made out of normal rails should be out of reach from the falling mobs.

Spider Falling Grinder[edit]

To make a spider spawner grinder, the fall chamber will need to be at least 2×2. A video tutorial on this is available here.

So to make this:

  • First, put water under the spawner on one side so that it will all flow into one direction.
  • Where the water ends, dig a 2×2 shaft at least 20 deep (best to do more as they sometimes grab the wall and reduce damage)
  • At the bottom of this chamber make a little room with a ladder or stairs to the surface or the base, etc. Down here is where the player will collect the drops.
  • Remove all lighting from near the spawner and make it completely dark, but light the bottom chamber to prevent anything spawning in the collection area.
  • Note that it would be smart to dig under the spawner and look for any cave systems, light them up so nothing spawns, this will increase the overall yield.
Anvil Smasher[edit]

It is possible to grind mobs by smashing them with an anvil. To do so, they should be contained in a small, inescapable chamber (preferably 1×1) with an open ceiling and a tall pillar on one "wall" of the chamber (the more placed, the more efficient). Then, a player may climb to the top of the tower and drop an anvil into the hole on top of the mobs. If they are dropped from a sufficient height, all mobs will be instantly slaughtered. Players may collect drops by means of a hopper or by going in. The anvil will, however, need to be manually retrieved. A way to bypass this would be to place a torch or sign at the bottom of the shaft to destroy the anvil straight after killing the mobs. Again, using a hopper would bring it back to the player along with the loot.

1×1 Fall Chamber[edit]

This is a good method of killing mobs and getting their drops. How to set up:

  • Dig a 1×1 hole down at least 23 blocks. With fall damage mobs don't take damage for the first 3 blocks and take 1♥ damage for every block over 3. So to do 20 damage (10 hearts) the needed distance is 23. If the player wants them to drop experience, the distance needs to be 22 so they survive with 1 health left, then a player must deal the killing blow. This will work so long as any player deals damage to it, whether it's the final blow or not.
  • Connect the bottom to some stairs leading to the house. The player will go down there to get the drops.
  • On the top, make a piston disappearing floor using a sticky piston and a NOT gate. See Tutorials/Piston Uses for more information on this.
  • Connect the floor to a lever in the house.
  • Build fences all around the hole and connect to the mob farm.

How to operate:

  • Wait for the mob to stand on the floor.
  • Pull the lever.
  • Pull the lever back, then go down the stairs.

Note: This will not work with chickens, ghasts, or blazes due to their flying ability. This will also not work for spiders as they need a 2×2 minimum to fall and often grab onto the edges of walls and reduce fall damage. Ocelots, snow golems and iron golems are also immune to this because they do not take fall damage. Make sure the player can see the grinder from the lever, so they know when to pull the lever. The player can make more holes and make this bigger. Just repeat the process.

Another tactic is to place water on a higher area so it is flowing. Put the hole at the end of the water. Doing this in a large row and inside a completely dark building is recommended, so mobs will spawn even in the daytime. The player will need a separate shaft connected to it in order to retrieve the dropped supplies. This is advantageous because it will work by itself 24/7 and is fairly simple to build. Once completed, all the player has to do is look for stuff on occasion. The player does not have to watch and wait for a mob to walk into place, and this works with any mob, even ones that can fly.

Magma Blocks[edit]

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Magma blocks are very simple to use. This machine generally takes a few blocks. However, they deal .25 heart damage, so they are pretty gradual to kill the monster.

Magma blocks can not kill wither skeletons or blazes so they can not be used in nether farms.

Magma blocks won't destroy items, and magma blocks can't harm players when sneaking.

  • Move mobs onto the magma block
  • Magma blocks kill mobs eventually (they sizzle out)
  • Flowing water pushes drops over a hopper or

After the mob has died, the hopper or Minecart with hopper will transfer the mob drops .

Magma blocks will be ineffective against witches as they can drink fire resistance potions.

Magma blocks will be ineffective against spiders as they can climb walls.

Mob Stacking Grinder[edit]

This trap consists of a single minecart rail at the bottom of a 1x1 pit that has 24 minecarts placed upon it. Water can be used to transport enemies into the grinder from above. They will be unable to jump out as long as the pit is at least 2 deep. The track and carts can be placed on top of a hopper to collect any items that are dropped. This grinder deals a lot of damage: skeletons and zombies die in about 2 seconds of exposure. It works by reaching the mob stacking limit of the game. When too many entities are shoved into too small a space they become damaged.

The downside to this trap is the high expense, since it requires 120 iron for the minecarts alone. Its also annoying to remove if the player needs to make changes to their trap. It also generates a lot of noise from the carts continuously trying to resolve their collision issues. Carrying 24 carts at once will take up most of the player's inventory so its somewhat inconvenient to transport.

The upside to this trap is it is extremely fast, compact, it does not destroy items, and is easy to combine with a hopper. It also works on mobs that are immune to fire and lava, such as zombie pigmen.

To place the minecarts efficiently it is recommended that you make a bottom block along one edge of the pit a half slab. This way you can easily access the rail on the bottom and place all the minecarts without losing line of sight of the rail.

Mob Grinders for Bedrock Edition[edit]

Trident Killer[edit]

This page demonstrates the use of MCPE-46369 to make a contraption.
Bugs of this nature may be fixed at any time without warning. When this happens, the contraption will cease to work.
Use at your own risk.

Trident killers are completely automatic, but the mobs drop items and experience as though they were killed manually. They work by throwing 1 or more tridents onto the ground, and having pistons push the trident(s) around. When the moving trident makes contact with a mob, this tricks the game into thinking that you threw a trident at the mob. As a result, the game registers this as a player kill. In multiplayer, whoever threw the trident(s) must be on the server for this to work.

The trident never despawns, meaning that it can remain in the kill chamber. Because the trident only needs to be thrown once, it does not run out of durability.

If the player holds a Looting sword while using a trident killer, the enchantment is applied to any mobs killed by the farm. In multiplayer, the player who holds the Looting sword must be the same as the player who threw the trident(s).

Many advanced players consider trident killers to be essential to mob farms, since Bedrock Edition does not yet have the sweep attack. They are more difficult to build in 1.13.0 and later, due to MCPE-54842, but are still possible.

A slightly more advanced design pushes the items and experience out of the kill chamber. This allows for farms with multiple trident killers, all of which deliver the experience to a single AFK spot.

Bedrock Edition Funnel Fall Damage Grinder[edit]

This trap design may not be as efficient as some other traps, but it works well, is safe for the player, and is easy, albeit slightly time-consuming to construct.

The first thing the player needs to do is find a body of water. This should not be overly hard to do. It doesn't matter how big the body of water is, it just needs to contain a water source block. Walk a few steps away from the water source. 3-7 blocks are optimal, but the player can go anywhere as long as they can get water from the source to flow there.

Now dig a 2×1 hole. When finished, the player can go up, and any block will do. To go up, tap the screen immediately after they have jumped. The player should dig down at least 23 blocks. When they are at the bottom, make a 2×1 hallway that extends four blocks away from the shaft. This would mean that the entire length of the hallway is 5 blocks, including the shaft.

At the end of the short tunnel, that is the fifth block, dig one block down. Now make a straight staircase back to the surface. If the player were to walk from the bottom of their shaft all the way up to the surface, the player should not turn.

Another alternative is if the player makes a large tower up for at least 25 blocks and a hole for them to fall through. The spawn area should be fairly large.

When the player is at the surface, walk back in the direction of the shaft. When the player is two blocks away from it, dig another shaft straight down. The player should emerge from this shaft in the hallway that has been dug earlier. Remember to keep this all lit up so that monsters do not spawn prematurely. Go back up the stairs. Go back to the holes. The player may want to temporarily block the first hole to avoid falling into it. The player is now going to create their mob farm.

Make a two-block high wall directly around the hole. Make a 2 wide ledge around the upper layer of the wall, like this: This is a top view of the structure, the numbers represent how many blocks thick the wall is. O is the hole:

  1 1 1 1 1 1 1
  1 1 1 1 1 1 1
  1 1 2 2 2 1 1
  1 1 2 O 2 1 1
  1 1 2 2 2 1 1
  1 1 1 1 1 1 1
  1 1 1 1 1 1 1

And a side view:

  c c c c c c c
      c c c

Next, build a two high wall up from the outer ring of the ledge. Build a 2-thick ledge around the top of this wall. Continue doing this until the player feels the mob farm is big enough. Cap it off with a roof. Its silhouette should end up looking something like this:

  c c c c c c c
  c           c
  c           c
  c c       c c
     c      c
     c      c
     c c  c c 
       c  c

If the player falls into it, they will not be able to get out without placing extra blocks. If the player falls down the hole, the player will die. Be extremely careful, and if the player does end up getting trapped, remember to remove all the blocks they used to get themselves out. Make sure that there are no sources of light in the mob trap. Go back down to the staircase. Place a ladder in the block between the first and second holes. Go to the fifth block, the one where they have dug one down. Place blocks over the fourth block so that the player has a window that can be seen into the trap from where the player is standing, but the monsters should not be able to get out. Glass is used this time for this step. Place another ladder beside and above the player. Here's a side view:

  c    c    c
  c    c    c
  c    c    c
  c    t    g
  c    l    l
  c c  c  c  

C is cobblestone, or the building material. G is glass. L is ladder, and t is an optional torch. Go back up to the stairs. Go to the first hole, unblock it, and let water from the nearby source block flow down it. Go back down the stairs. The player should be able to see the water as a column. Soon, monsters will come crashing down the second hole. When this happens, break the ladder that is beside the water. The water will flow over to the player and be stopped by the second ladder. It will bring the monster's drops and the ladder. Put the ladder back in its place, underneath the torch. If a monster falls down while the water is flowing, it will not die. However, it will be very easy for the player to kill it by striking at its feet. Creepers will not blow up and skeletons will not shoot players because they cannot see them. The trap is complete, enjoy the spasmodic monster drops and having the living daylights scared out of the player the first few times a monster falls down the hole.

Bedrock Edition fall damage grinder[edit]

A view inside the completed Bedrock Edition mob farm/grinder.
A view of the staircase back to the surface.
The outside of the completed mob farm/grinder.
Collecting the drops.

Alternatively, it is possible to set up a standard water channel fall damage mob grinder in Bedrock Edition, but the locations that they can be created are more limited, and the player can only create the water channels one layer tall. This is only true before version 0.7.0.

The player will need to find a wide area of shallow water, preferably at least 18×18, and no deeper than 5 water blocks. Working on ice is even easier. This build relies on the fact that solid blocks can replace water source blocks.

Simply build a standard 4-channel configuration, but fill in all the water blocks except for the two at the end: (top view)

                X X X X
                X W W X
                X S S X
                X S S X
                X S S X
                X S S X
                X S S X
                X S S X
X X X X X X X X X S S X X X X X X X X X 
X W S S S S S S S     S S S S S S S W X
X W S S S S S S S     S S S S S S S W X
                X S S X
                X S S X
                X S S X
                X S S X
                X S S X
                X S S X
                X W W X
                X X X X

Now, dig down in the center 23 blocks down, then laterally 10 blocks, then build a staircase back up to the surface.

Once back up top, put a 3-high wall around the structure, and fill in all of the remaining water blocks with whatever material the player has. Dig out the sand blocks shown above to start the flow of water, and put a roof over top. Litter the top of the roof and surrounding areas with torches, then go downstairs and start collecting the drops.

The player can also add multiple layers with reduced efficiency for subsequent layers. Since water source blocks are only reliably present at sea level, any subsequent layer will be dry farms. Build additional 3-high walls on top of the previous structure, put a new roof on it, then dig out some of the floor blocks to expose the area beneath. The more blocks the player have removed, the more likely mobs will fall, but the less likely mobs will spawn. Checker patterns of 3×3 blocks or simply removing 2× blocks on the diagonal seem to work. Then, remove the torches, dig out of the new layer, seal it up, and replace the torches on the roof. Repeat as materials allow.

At this time, the only drops the player can get are rotten flesh, arrows, string, and gunpowder.

Another easy way to build a fall trap is to start out with multiple (around 7-11) stacks of 64 dirt or any type of stone. start by building a 4×4 tower. The player doesn't need to have it be specifically 4×4 though. Any size will work.

Build up until the player reaches a lethal height. Once at that height expand to the sides of the tower about three blocks and build a wall and roof. Jump down respawn and collect the items the player has dropped. Now back at ground level make a doorway.

The spawn room should be too high up for sunlight to get in and affect the spawn rate hence light didn't need to be worried. The next step is optional but recommended because the player won't get mobs falling on and hurting them when the player collects the drops. All the player needs to do is make a river flowing to a collection pool. Then, they will have an easy effective and pretty cool looking fall trap.

Bedrock Edition Multi-Level System[edit]

With the addition of buckets to Bedrock Edition, many different opportunities to farm monsters have come. Here is a practical design that yields well over 400 drops per hour when properly set up. Before building the spawning chambers, a good idea is to create an infinite water source, so the player can refill the buckets when the water has been used. To start the spawning tower, build a 2-block tall 22×22 block wide ring of some building materials. Then add 4 7×7 rings of cobblestone 2 blocks away from the sides of the larger ring that was previously made.

The smaller 7×7 rings are 2 blocks away from the side of the larger 22×22 block ring.

Once the player has made all 4 smaller rings, add water source block in 2 spots in the 4 corners.

Two source blocks go in each of the 4 corners.
Once the player have placed all corner sources, the water should end at the 7×7 rings.

As mentioned, place the water in all 4 corners. Once the player places all the source blocks in the corner, the water should end where the 7×7 rings of cobblestone end. At the center of the 4 7×7 rings, place 2 source blocks.

Once again, the water sources are placed in the center, diagonal each other.

The water should flow all the way to the end of the 7×7 rings. Then fill in the 7×7 rings with the preferred solid block. The bottom part of the chamber should now be finished.


The following grinders can be effective in the right situation but are less common due to size, inconvenience, or other disadvantages.

Cactus Choke[edit]

Cactus Choke

This mob grinder is for killing off spiders, sorting out spider-size/spider-jump/spider-climbing related issues. This is a simple design, relying on the spider's 2×2 size and jumping ability. The grinder stops all spiders at a bottleneck, where the water-conveyor narrows from 2 blocks wide to 1 block. A cactus is placed on the side, on top of a sand block (make sure the cactus is out of the water, so it doesn't destroy the drops).

Alternate Cactus Choke[edit]

Alternate Cactus Choke

Similar to the above cactus choke, but more efficient and items won't get stuck behind the sand block. At the end of a stream, there is a small gap with a stream and a cactus behind that. This allows cacti to kill spiders without having them climbing to get to the cactus. This can also sort mobs from spiders similar to the above cactus choke if done right.

Fall Damage Mob Killer[edit]

Space permitting, fall damage can be used to dispatch mobs. This style of mob grinders doesn't work for chickens since they glide rather than fall. Spiders should be sorted out before they are dropped as they can climb the inside of the drop-tube and potentially clog it. Mobs must drop from at least 23 blocks to receive fatal damage. Use a water column full of source blocks to float mobs up at least 28 blocks. At the top of this column of water, have another stream push the mobs into the drop-tube. This tube helps prevent skeletons from firing arrows at the player while they are falling.

If desired, a control lever can be built that will collect mobs at the top. This can either toggle a door or piston, both designed to artificially clog the machine until released.

Here is a how-to on a simple but effective Fall Damage Mob Trap/Grinder.

  1. Construct a 20×20 platform of any solid block 28 blocks high above the ground.
  2. Make walls surrounding platform six blocks high.
  3. Inside the walls, make four water channels coming from the middle of each four walls to the center. This should create a 2×2 square of dry blocks in the middle. Cut out that square, that will be the hole the mobs fall through.
  4. Make the channels 2 blocks high so mobs can't jump out of them.
  5. Make four platforms between the four corners that the water channels create that are flush with the top of the water channels (this will be the area that the mobs spawn on).
  6. Make a roof over the whole thing. The player should be able to walk around inside the spawner with a space 3 blocks high. A second layer of ceiling blocks can be added to prevent endermen from spawning.
  7. Remove any torches to make it dark inside.

Fall Damage Experience Grinder[edit]

When a skeleton, zombie, or creeper (which have 10 hearts of health) drops 22 blocks it will leave it with one half-heart of health left. Endermen have 20 hearts, so at 42 blocks, they will have 12 of a heart, and spiders have 8 hearts, so they need to fall 18 blocks, and the hole has to be 3×3 or bigger to prevent the spiders climbing the walls. A canal can then carry them to a hole in the wall, where the player can reach in and punch them to gain both experience and the drops. This works best when the player makes this in a dungeon. Firstly, make water flow to a 1×2 hole in the dungeon. Then, have water source blocks alternate with signs to the desired drop height. At this point have water flow to its end and then mine down to the place where the mobs hit. It is best to leave them with half a heart because mobs do not disappear over time, but pickups do. Then mine a pathway to the house. Then go back to the fall point and place a block so that only the mobs' legs are showing so that they cannot hurt the player. Then they have a working mob trap.

This video provides an example of the gathering mechanism that leaves only the feet showing. It does not use fall damage, but rather relies on the player to just hit the mobs.

Sunlight Death Chamber[edit]

Zombies and Skeletons burn in sunlight which can be an effective way of dealing damage and separating creepers. This can also be done with monster spawners, a tutorial is available "here" . A sunlight death chamber is simply a room with a glass or a hollow ceiling. This is a very simple mob grinder to make but has several downsides:

  • Daytime. Only the sun can burn these mobs, making this useless at night and when overcast.
  • Unblocked. No blocks can be directly above the trap (with the exception of glass).
  • Dry. Water extinguishes fire and since the mobs burn, no water can be present in the chamber. This can be simplified by having a valve which can be shut off during the day.

Mob arena[edit]

Strictly speaking, this is not a mob grinder but does have a similar outcome and is a way of using the mobs spawned from a mob farm. The mobs are collected in chambers and slowly released into the arena to fight against players.

The concept is simple, 2 tall buildings, with about 15 rooms inside, that have holes at all corners, and water around the sides to push anything that goes to the side into the hole at the corner. Then once the mobs fall down, they are trapped in a simple holding area until a lever is pulled to let pistons open so that the mobs can fall out.

Video explanation and showing the concept at work: "Youtube"

Egg Spawner Grinder or "Mob Vending Machine"[edit]

With the addition of the mob spawner eggs in 1.8, it is possible to create an egg spawner based grinder. Very useful for getting mob based items such as bone and rotten flesh in adventure maps, but useless in survival because it requires spawn eggs.

The player will put an egg over a block which has a sign or a ladder blocking the water in the upper layer to flood down and at the same time pushing mobs up, then they go through a corridor and falls in a 1×3×5 corridor covered in the upper block with air, midblocks with cobweb or air and in the down block with water and with a dispenser that shoots fire arrows with a clock mechanism. It is possible to shoot the eggs with a dispenser creating a "mob item vending machine".

The player only needs to be careful with one thing: never put creepers with other mobs in the machine because if they start to fight inside the water canal, the creeper could blow up and destroy part of the machine. This would cause lava to flow outside of the machine, potentially killing the player. However, it is secure to put creepers alone in the machine. Also, the overhang in the egg placing area prevent creepers and other mobs to attack the player as the water pushes the mobs up at the moment that they spawn.

To automate the entire mechanism, place a dispenser in the egg placing area, stock it with eggs, and connect it with redstone to a button. Connect a lever to a clock mechanism to shoot the arrows. From here, it's just a matter of pressing a button to spawn a mob, and then using the lever to launch arrows at it.

Grinder vending.png



To retrieve the drops without any chance of despawning, put a hopper in the ground/floor at the end of your water flow or wherever your items drop out. Put a double chest under the hopper, and make sure to go empty the chest before it fills up and items pile up outside. The simplest way to do it: W=Water, O=Air or Block, H=Hopper