dinochess14
Terrarian
The Mechanics of Lucky Coin farms
Using the lucky coin to farm money with an AFK farm is nothing new, it has been popularized for years, with a redesign being done after 1.4 change the AI for aquatic enemies. You will usually see an AFK money farm being using Arapaimas, using a slime staff to hit each enemy 5 times a second. This design has been used for a while, but I have come up with some major improvements to the standard design.
The Lucky Coin
The enemies
Arapaimas have been used for some very important reasons, firstly that they are easy to consistently spawn. When in the jungle biome and the game spawns an enemy in the water, it will be an Arapaima 2/3 of the time. Arapaimas also take up less than a full NPC slot, which is very important. There can only be 15 NPC slots filled during normal circumstances, only being bypassed by certain events and by the For The Worthy seed bonus to enemy spawnrate and maximum NPCs. Since Arapaimas take up 1/2 of a slot you can have 30 Arapaimas active at a time, which means the Slime minion gets (30 * 5) 150 hits per second. Using our average of 1.22 silver coins per hit this means an average of 1 gold 83 silver every second. The last reason is their large health pool, on Master mode they have 600 health, which means each Arapaima is worth 600 hits as long as the Slime minion does 1 damage per hit. Using our average of 1.22 silver coins this means that every time an Arapaima spawns it is worth 7 gold and 32 silver. How fast the enemies die depend on the minions or other attacks used. Using a convenient guesstimate of 1 enemy spawning every second, which is not too unrealistic with spawnrate boosts, we want to be dealing a total DPS as close as possible to the maximum health of the enemies. If it is above the total health pool then the bottleneck will be not enough enemies spawning, if below then the bottleneck will be how fast we can get hits in. If we never go above 600 hits per second there is no reason to use anything other than Arapaima, but if we do cross the 600 mark then it would be more efficient to use another enemy, more specifically another enemy that takes up 1/2 of an NPC slot or less, has consistent spawning, and has more than 600 health. There are a few enemies that could be used, but by far the easiest is the Black Recluse, which has a 90% chance of spawning if in front of a natural spider wall, and will be replaced by a Wall Creeper the other 10% of the time.The Minions
The most popular minion used in Lucky Coin farms is by far the Slime minion. It is very consistent, but there is a problem with it. The Slime minions use static immunity frames, which means that one Slime minion will keep any additional Slime minions from hitting the same target. The Slime minion also has an immunity time of 12 ticks, which means it can only hit 5 times a second. With 30 enemies this means 150 DPS which means the enemies spawning in is not the issue, in order to be more efficient we need to get more hits in. Another option is the Vampire Frog minion, which can get slightly more hits in on its own if it is consistently hitting all the enemies. The Vampire Frog also uses static immunity frames, but it has a cooldown of only 10 ticks, meaning it can hit 6 times every second. The Flinx minion is the same, using static immunity with a cooldown of 10 ticks. Using all three of these minions with each one hitting the maximum number of times per second you get a total of 17 hits per second, which with 30 enemies is 510 hits per second, using 1.22 silver coins as an average we get an average of around 2 gold 7 silver per second. There is another summon we can use however, the Finch minion, which unlike all the other minions uses local immunity frames, meaning one Finch will not keep additional Finches from hitting the same target. There are a couple downsides however, the Finch hits slower than all the other minions, having a cooldown of 15 ticks, or only 4 hits every second. The major dealbreaker though is just how bad the Finch AI is. For the other minions you can more or less just put them in a box with the enemies and they will perform just fine, not so with the Finch though. The Finch loves to fly around its target, repeatedly missing it, even while it is perfectly stationary, and even if it could reliably hit the target the movement of the Finch would drastically reduce the number of hits per second. The Finch does have a redeeming feature though, it collides with blocks, or at least it does under specific conditions. If the player has a clear line of sight to the Finch's target the Finch will be stopped by blocks in its path, making the Finch stand perfectly still. This means that as long as we can make the Finch stationary, all we have to do is make the enemies run into the Finch for more hits per second than any other minion on its own. With 6 minion slots (Spider armor + Pygmy Necklace + Bewitching Table) we can use a Slime, a Flinx, a Frog, and 3 Finches, leading to a total of 29 hits per second. If we can have all these minions concentrated in one spot with 30 enemies we will have a total of 870 hits per second, or 10 gold 61 silver per second. Note that this is also more than the health of an Arapaima, which means that Black Recluses will be more efficient.The optimized farm
The basics
Knowing that the most efficient farm would use Black Recluses and Finches all we need is a build that will cause Finches to stay still and cause Black Recluses to stand right on top of the Finches. After some experimenting I came up with the following.The basics
Any statue with an enemy that does not teleport, turn invincible (Granite Golem), change states (Wall Creeper from wall form to ground form), phase through walls, or shoot projectiles should work, Blood Zombie, Armed Zombie, Undead Viking, and Skeleton Statues all work very nicely. Simply right click the statue enemy with a summon weapon and then summon the Finches on the other side of the blocks. I believe there is also a distance requirement from either the Finch or the player to the statue enemy, I noticed it would not work when the statue was too close but I do not know the exact distance where the Finch will not get stuck on the blocks properly. Using this simple design we can create a basic enemy farm very quickly.
Making the basic farm
As with all farms I highly recommend making the farm in pre-Hardmode if you are planning to use it once you get the Lucky Coin. Mining and building in pre-Hardmode is so much easier than trying to do it in Hardmode with the tougher enemies. To start, simply clear out a large area (minimum 168 horizontal by 94 vertical) in the Cavern layer, removing a Mushroom biome with Gravedigger's Shovel and mining gear or simply using explosives is the quickest way. Mark a spot in the middle as the spot where you will be standing, Ice Rod is very helpful for placing blocks in midair. I used the left side as the side that spawns enemies but you can easily mirror the setup and use the right side. On the side that you want to spawn enemies place a row of blocks at the same height you will be standing, make sure they reach at least 84 blocks to the side, Binoculars and the ruler tool or the Kwad Racer Drone if you are post-Plantera are both very helpful for measuring longer distances. Make sure to place a layer of lava below the farm to prevent unwanted enemies from spawning. Place Infested Spider Walls (Throw Spider walls into Shimmer) behind the layer of blocks. Here I use a simple gate with actuators to prevent spiders from entering when I do not want them to. Making the optimized farm
Optimizing the farm is simply minimizing the time it takes for the spiders to get in the right place, which we can do with teleporters and hoiks. Setting it up does take more work than the basic farm, but the effort is rewarded. In ten minutes with 6 minion slots the current version of the optimized farm got around 56.5 Platinum Coins, which would be around 340 an hour, or 60 more an hour than the basic farm. Whether or not its worth it for all the extra wiring and placing walls depends on how much use you're going to get get out of the farm.
The farm went through quite a lot of changes, trying different methods until I found one that worked exactly as I wanted it to, the teleporters are placed 3 blocks below the block the spiders spawn on, and the receiving teleporter instantly kicks them up a block to avoid any double teleports, which was a big issue in previous designs. There are still a few double teleports that are caused by the spacing of the teleporters, but with the width of the spiders it is hard to avoid overlap, you could potentially make a version with only certain areas the spiders spawn in, but whether or not its worth it is debatable. The order you hook the teleporters to the receiving teleporters should not matter. I used Fireworks Boxes to trigger them every two ticks, but you could just use two 1/4 Second Timers and be just as well off. You can even hook all 8 teleporters to the closest teleporter to minimize the time it takes for the spiders to reach the kill-spot, it does sometimes teleport the spiders there and back again like Mr. Bilbo, but if you're activating them frequently it should still be faster than having multiple exits. Using the teleporter order of operations it may be possible to devise a system where it always teleports correctly, I'm not sure. The conveyor belts really aren't needed, I used them to try and pick up the coins a bit faster but they did not seem to do much if anything, you can just replace them with regular blocks. The farm does actually break in multiplayer when using too many minions because the item limit is hit before you can pick the coins up, so it hurts the AFK ability of it but if you use it in singleplayer you can push it even further. With 10 minion slots you can reach 400 platinum per hour, and if you use 10 minion slots on a For The Worthy world you can actually reach 600 platinum an hour due to all the boosts to enemy spawnrate, max enemies, and enemy health.
Fireworks Boxes make handy timers since a firework projectile moves at exactly half a block per tick. This means that if you have multiple Teal Pressure Pads lined up above the Fireworks Box like shown there will be two ticks between each pressure pad being activated. It does take 1 tick for the firework to reach the first pressure pad, but this can be changed by putting the Fireworks Box in 3 blocks of water as shown, which will slow the firework down enough to make it take 2 ticks to reach the first pressure pad, which is very convenient for looping timers. Fireworks Boxes can only be activated by wire every half second or 30 ticks, so in order to make it loop you have to use at least 30 ticks or 15 blocks of the first firework fired. I used Fireworks Boxes to activate my teleporters, but you can use any method, 1/4 Second Timers work just fine.
Summary of average coin gain per hour
Basic farm (no teleporters/hoiks) with 6 Finches: 250 Platinum/hour
Basic farm (no teleporters/hoiks) with 1 Slime, 1 Frog, 1 Flinx, 3 Finches: 280 Platinum/hour
Optimized farm with Slime, Frog, Flinx, 3 Finches: 340 Platinum/hour
Optimized farm with Slime, Frog, Flinx, 5 finches: 381 Platinum/hour
Optimized farm with Slime, Frog, Flinx, 7 Finches: 405 Platinum/hour
Optimized farm with Slime, Frog, Flinx, 7 Finches on For The Worthy: 600 Platinum/hour
Alternate setups
As far as the hoiks go I will show some of the previous versions just for the sake of it. The version shown directly below was made by ARK | Quasar#6944 on the Terraria discord server and instantly kicks the spiders into the final spot. Something like this could be faster than the previous build by a couple ticks per spider. The other two builds are the main builds previously featured on this post in case you want to look at the older versions of the farm.
Hoik version by Quasar
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