I'm trying to create an iron golem trap, and while I can create huge ones (see screen shot below) I'm interested in making smaller ones. I have tried several different variations, including this one, and they don't seem to ever spawn a golem. There are tons of examples of farms on youtube, but from what I can tell they're all 1.2.2, granted farming in 1.2.5 is pretty inefficient, but I'm still interested in doing it. What am I doing wrong?
12 doors on a side with 4 villagers per side. The vilage 'center' is the middle point between the the 'doors' that are considered to be part of the village. The golems will spawn in the middle and fall thru. DocM has a nice tutorial on youtube describing the mechanics in detail. 20x20x8 footprint for the main cells.
It could be that your layouts dont lend themselves to having a natural 'middle' Even the 2nd picture with the doors all clustered together in the middle, there might not be room for the golem to spawn because the doors are there.
A village has to have over 26 people for an iron golem to spawn. I think it might only spawn when there is a risk to the town or the villagers are free to wander around the village.
I've built several variations of Iron Grinders based on classic design. Then I found Nims Tutorial on his ultra compact design.
It's awesome - roughly 12x12 (Get your doors correct). I use it all the time. You can build it one block above the surface and drop the golems into your underground lair. There's no need to build the Redstone filter system really. But Hoppers to fill more double chests don't hurt.
Just heed the warning, you cannot have anything but glass within 5 blocks in any direction of the chambers. Even 1 block, and you'll always find your golems spawning on it.
If you have Residence protection, make sure that clearance exists. If someone builds in that 5 space air gap, you're golems will escape.
My personal project is a One Chunk facility - Gold (Nether Frames above Iron Grinder), Iron & Zombie spawner grinder. In one chunk which makes for faster loads, etc. Park this "Machine" in a spawn chunk and go AFK - score.
I've been experimenting with Nim's Version and still am. Instead of lava, I tend to use cacti - slower but easier to get and less dangerous. I've got Nim's version double & triple stacked with corner ladders so the villagers can mingle and breed - not necessary. I've another design I'm testing with a layer of doors sandwiched between the golem spawn chambers so I can increase the villager to door count.
I'm also looking at the MC Wiki's for a better understanding of the door (Home) mechanics to find further gains & output.