Tutorials/Mob farm

Overview
The purpose of a Mob Farm is to automate and maximize the process of spawning mobs, killing them, and funneling the resulting items to a collection point. There are many versions, techniques, and sizes, all with debatable levels of success.



Canal-style Farm
This type of farm is a large underground cavern with interlocking canals used to funnel mobs to a central hole. From there, the mobs are transported to a simple lava killing device, and the resulting items are filtered downstream to a collection point. This collection point is far enough away from the cave that you can AFK there without disrupting mob spawns.

Inspiration for this tutorial, and original concept, was made by Mokomi, found on YouTube (http://www.youtube.com/watch?v=HdKBeInv_2s).

Preparation
Before embarking on this project, keep in mind the raw digging alone can take several hours. You are going to want to stockpile sticks for pickaxe and shovel handles and ladders before starting your dig, as well as at least two buckets with water in them. Later you will need to fill these buckets with lava, but we'll get to that later. I would also recommend creating a workbench, up to two furnaces, and up to four chests for holding tools, supplies, and materials.

While digging the farm, you will undoubtedly come across plenty of coal and iron to help replenish your tools, but because of the depth you will be digging at, finding diamonds will be highly unlikely. If you want some diamond tools, gear up before digging.

Digging the Shaft
Your first task is to dig downward. A straight shaft is recommended, using alternating ladders. You will want to dig all the way down to bedrock. Hollow out a small room of about 5x5x3 blocks. This will be your target for the collection of the items.

Now count blocks back up your initial shaft. You want to dig another room with the floor being the 16th block up from bedrock. If you want to be safe, err on the side of going higher (17th block is fine). You want to make sure you have enough room to not only dig your canals, but also the resulting funnel and item collection stream. Remember, your target is that little room on bedrock!

Make another small room, about the same size, right above the other room on bedrock. This will be your base of operations, so get comfy! Place your workbench, furnaces, and chests here in whatever fashion pleases your design sense. Then, dig a 4-block-long hallway into the wall adjacent to the mine shaft. This will allow you room to place a door, but also enough room to fill it back up with dirt or stone later. You will want to remove all light sources into the farm when you are done.

Digging the Cavern
Now comes the tedious part! You will need to dig a 50x50x2 cavern. Everything must go! I kept my little hallway in the corner of the 50x50 plot. Then, just pick a direction and start digging out. If you choose to dig out and right, your end funnel will need to come back left to meet up with the basement collection point, and vice versa.

It is also recommended that you keep the height to 2 blocks to promote more sideways movement of the mobs, and prevent them from jumping over or out of your canals. If you hit gravel, fill in the hole to make the ceiling level.

If you want, you can alternate digging the flat cavern with digging the canals. If you choose to do this, read through the rest of this guide to understand the whole project first.

And most importantly KEEP THE CAVERN WELL LIT!! You will be working around in a large underground area. You will, at some point, want to return to the surface, leaving your cavern to become prematurely populated with mobs, and that's a bad thing. I put torches on the wall every 5 blocks (also using double torches to help mark canal placement) and in the central squares, I generally used a layout much like the '5' on a six-sided dice. It might also be a good idea to keep the difficulty on "Peaceful", so you don't have to worry about it.

Digging the Canals
Great, depending on how you decide to tackle this project, you may be finished with the whole cavern by now. If so, awesome! Now is time to start digging our canals. They will cover a good area of the floor and use water streams to push mobs into the center. I have included a map of sorts for digging these canals, as the height and placement of the canals is important for keeping the water flow constant and free of any "dead zones", or still water mobs can get stuck in.



(for the full size file: http://www.minecraftwiki.net/images/4/45/Main-design.PNG)

There are a couple of keys to digging your canals. First, always precede any intersection with at least two blocks that are level with the intersection. Having water *fall* into the intersection causes some weird water flow and can cause those dreaded "dead zones".

Second, the ends of the main canals, or the ones that form the large cross in the middle, start 2 blocks below the floor, not one. This is, again, important to maintaining a good flow throughout the canals.

You may feel tempted to test out your canals before the project is complete. While I normally recommend testing your project as you go, I might try to resist the temptation here. By having water flowing through your canals as you are constructing them, you could find yourself fighting against the current, severely slowing your work. If you must test, make sure to remove the water before continuing your dig.

Digging the Funnel
We're almost ready to flood these canals, but first we have one more project: the funnel. This is a tunnel that will start at the hole in the middle of our farm and extend out. Remember, if you started digging out and right from your initial base, this funnel will need to head back left, and vice versa.



Start by digging down 3 blocks in the center 2x2 area of the farm. Then begin digging your 2 tall 2 wide hallway. You will be digging over by 7 blocks, then dropping down one. This will keep flowing the water from just two source blocks at the top of the funnel.

Dig over 7, down 1 three times. At this point, dig over 8 this time, and down another one. This last 8 will prevent water from bumping into the ladders you will be placing later. At this point, you will want to create your lava trap. For that, see the above image for the funnel cross-section.

You will want to dig a 2 wide, 1 tall, 3 deep hole that is level with the ceiling. Place two ladders below this hole. This will suspend the lava in the air, but allow mobs to flow right into it.

Once you have your lava killer ready, it's time to start digging the collection stream. This stream will only need to be 1 wide and two tall (only so you can fit through to dig it!). You'll place a water source block under the lava on the opposite side as your collection stream. Remember, you're trying to aim back towards your original bedrock room!

You should have to dig about four sets of 7 over, 1 down to reach your room. Once there, you can do almost anything from just letting the water spill out the items, to placing a system of Pressure_Plates and redstone wire to alert you to the presence of items. This might be a bit overkill, as I can assure you if everything went according to plan, you will ALWAYS have items waiting for you!

EDIT! In the latest update, spiders can now climb vertical surfaces. In the funnel, this can be a problem as then can clog up the works. User Yamitatsu proposed a little more digging in the funnel to prevent the clogging effect if a spider actually does manage to get trapped by the canals. I assume this recent update will essentially halt the production of string by this farm, but what do you really need that much string for anyway?



Placing the Lava
Now it's time to light the fires! This is best done before filling the canals so you aren't fighting a current when placing these blocks. Place two lava source blocks in the back of your lava killer. If all went well, you should have a thin layer of lava suspended above the ladders you placed. Once that's done, head back upstairs for the final steps.

Filling the Canals
Now it's time to get this farm working! Remember those two buckets of water you came down with? Time to put them to use! Create an infinite spring somewhere in your floor. Near the middle might be a good idea! Then drop water source blocks at the very ends of all the canals. If you have extra iron at this point, make up a few extra buckets to speed up the process.

Once all the canals are started (this is a total of 32 water source blocks) take a walk around your farm and check for "dead zones". If you see any standing water, you're in trouble. Remove water source blocks to drain the affected area and check the depth map again for any irregularities.

Removing the Torches
Now it's time to plunge your Mob Farm into darkness. Remove all the torches in the cavern in a circle around. Start at your base hallway, pick a direction, and run! Inevitably mobs will spawn during the process, but hopefully your canals will funnel them safely away. You'll probably have items waiting for you by the time you are finished! If you want to be safe, just pack all your tools and such into your chests so it's not terrible if you die.

Covering the Door
The last thing you want to do is to place a couple of blocks (your choice) over the entrance to the hallway to the farm. To maximize mob spawns, you don't want any light getting in, even through those tiny door windows. I also place a sign on this section reminding myself not to dig there. This can also come in handy on a multiplayer server to prevent others from stumbling into your farm (as hilarious as that might be!)



Final Thoughts
This project demands a lot of work! It took me about 5-6 total hours of work, but I was trying to figure everything out as I went. You might find it takes you significantly less time with this guide.

You can, if you want, create some viewing rooms down by the end of the funnel. With the length of the funnel, placing a couple torches down here in a glass room won't affect the mob spawning too much and it will give you a front row seat to watching the mobs burn!

I also hooked up a redstone torch and wire system leading back to the surface. Since the mob farm is constantly kicking out items, this light should always be on. It's more helpful in showing me if the farm ISN'T working properly, or when the light is off. This can tell you if something is wrong with your farm and that you should check it out.

Make it your own and if you make any significant changes for the better, feel free to let me know on the Talk page! Happy farming!