I made this iron farm from a video by a Youtuber called Pixlriffs which is based off someone else's farm whose name I cant remember.
I built it exactly as he said stopping every few mins when he placed a few blocks.
As far as I can tell everything is built block for block (other than the killing chamber which he didn't explain and the outer wall is approx 15 blocks below the villagers beds).
I have also read a few other forums but they don't explain much and are rather vague.
If anyone is able to give me some advice that would be great.
I am also playing on a multiplayer server but I didn't think that would change anything.
UPDATE: They also don't seem to be sleeping at night.
As can be seen in the image, one of them is sleeping but none of the others are.
Watched them for a while but only that one slept and he never woke up either.
ANOTHER UPDATE (just trying to get as much info out as possible so that someone may be able to help me):
I have been watching my farm for the past 20 mins or so and it has become night and a couple of the villagers are trying to sleep but everytime they do they seem to slide out of the bed and so get up. They then try to sleep again and slide out again, trying to sleep over and over. They stay on they block they are meant to when awake but they can't sleep and aren't being scared by the zombie.
Cant tell clearly from the picture but to me it looks as though the half slabs over the villagers is too low
It looks like you may have a upper halfslab just above the villagers while it needs to be a lower half slab a block above to allow the villagers to 'bounce up' so that they can see the zombie pass the trapdoor
My custom design not exactly the same as the one you built but you should be able to see there's a 1/2 slab gap above the villagers in mine while you don't
As for villagers sleeping/not sleeping - it happens normally.. I think it's a bug in the system since my Villagers tend to randomly not sleep either
You also need a carpet on top of the slab closest to the zombie. With the setup you have now, the villagers are scared but don't have the ability to gossip because they are constantly scared. The addition of the carpet will allow the villagers to gossip and spawn iron golems.
I built DOCMs mine like you did and and it never worked.
I am running Java 1.14.4 I am not sure what version Docm's design is ment for.
Then I build this one
and it started working within 10 min. I like it because it is small and compact and I can fit several in a compact area if need be(outside the 16 block exclusion zone of course).
I have watched a lot of iron mine vids and as far as I can tell the mechanics work like this.
willagers = 3
beds = 3
work stations =3
line of sight between zombie and villagers. make sure to include an area where the villagers can break line of sight periodically.
clear 16 block radius around the iron farm. Build it in the air or under ground but be sure there are not spawnable spaces withing 16 blocks of the area you want the iron golems in. You can make this farm with separate villager enclosures as long as they are at least 10 blocks apart.