This is the simple iron farm design from LogicalGeekBoy.
This design is made to be as simple as possible, so it does not have maximum output in comparison to other iron farms. It is intended for users who don't want to build a lot or do not need stacks and stacks of iron.
The farm will make about 7.4 stacks of iron per hour and does work at night. Just ensure that the first night of full assembly, the sticky pistons are pushed on to block eye line of the zombie to villagers so that they sleep at least once. Otherwise the golems will not spawn! Golems will be spawned approximately every 30 seconds.
Watch the video attached for more information or to watch him build the farm.
126 White Stained Glass (can use any block)
41 Stone Bricks (must be soild blocks)
6 Oak Sign (can use any type)
6 White Bed (can use any color)
3 Water Bucket
2 Cobblestone Wall
2 Lava Bucket
2 Sticky Piston
2 Stone Button (can be any type)
Raw materials for survival:
Total iron needed: 47
Total slime needed: 2
Approximate wood logs needed: 48
Side note: the torches are not required- I only put them there to prevent the water from turning into ice if built up high.