Dropper Item Elevator
This simple tutorial explains how to build an item elevator using Droppers. This is one of the simplest, and most useful, mechanisms in Minecraft.
You will need:
Three pieces of smooth stone to build a redstone repreater.
Optionally, if you also have some Nether Quartz to make a comparator you can build a fancy version that automatically switches itself on and off.
Build a tower of droppers
Start by placing a dropper on the ground so that the hole faces upwards:
Continue placing droppers (hold down SHIFT to sneak to place one on top of another) as high as you want. Here we've put a chest on top to catch the items that are sent up the column.
Add a simple clock circuit
Place some redstone and a redstone repeater as shown below:
The arrow on the repeater is pointing left to right. Right click once on the repeater to add a short delay to the circuit, otherwise the torch will burn out. When you finish, the circuit should start switching on and off (the torch switches on the repeater, which switches off the torch, which switches the repeater off, which allows the torch to come back on?). You can read more about clock circuits here.
Each time the repeater switches the block in front of it on, it will activate the bottom dispenser, making an annoying clicking noise.
Add a control lever
To switch off the annoying clicking when the column is not in use, add a lever as shown:
Connect the clock to all the dispensers
This is as simple as running an alternating column of redstone torches and blocks up the side of the column. This might be hard, depending on where you're building your dropper, so here are a couple of options:
Add a hopper feeding into the bottom dispenser, with a chest on top of it, and you're done.
Put items into the bottom chest, and they will pass through the hopper into the bottom dispenser. Flip the lever, and items will be carried to the chest at the top.
Fancy Automatic Version
If you have some Nether Quartz, to build a comparator, you can build a fancy version that switches itself on and off as needed. Add another block, with a torch on top of it, as shown:
This will stop the oscillator from ticking; you can get rid of that control lever if you like. Now add a comparator, pointing from the bottom dispenser to the block you just added:
Your elevator is now fully automatic! Any time there are items in the bottom dispenser, the clock will be switched on and the elevator will elevate stuff.
Because the elevator is controlled by the bottom elevator, it will switch off while some stuff hasn't made it to the top. In general, this won't matter; we find that 12 items get stuck in a 50-block-high elevator, and we're OK with that. It'll all make it eventually when we send up the next batch! If there's something important stuck in there, just chase it with some dirt or cobblestone!
However, if you're really fussy, it's no effort to add a lever to flush the column and send every last item to the top. Stick it on here, in front of the comparator:
This lever will short-circuit the comparator, and switch the elevator on to force everything through.
100% efficient fully automatic elevator
This is totally not worth the effort to build this, but here is a very simple design for an elevator that is completely automatic, and transfers every last item.