Here is an amazing map featuring 15 different redstone creations. Some of the included redstone machines are two TNT cannons, an advanced item sorting machine and an automatic iron ingot farm. But there's much more than that to discover. All of them are fairly easy to build and can most definitely be useful for your future creations in Minecraft.
Creator: Jhomes, Twitter Account
TNT Cannon: Ultra Shot Auto
A fully automated TNT cannon which fires long range TNT blocks. It's a very useful machine which you should setup at your base to defend against possible intruders.
Decide whether to enable fire arrows or just using the ordinary ones. Either way, it's a very powerful machine to quickly demolish enemies. A clear disadvantage is that it runs out of arrows after 30 seconds or so, but by then you've probably already killed your enemies.
TNT Cannon: Basic
The basic version of the TNT cannon. It doesn't fire as far as the ultra cannon but it's more easy to build and good for close range battles.
Virtually Infinite Storage
Place the items and blocks which you want to sort in the chest and then let the machine do the boring task of sorting it for you. The lamp will blink while it's working. You can place any items in the machine as it got loads of different item categories available and the items it doesn't know what to do with is placed in the "Miscellaneous".
Identity Security Card
Keep your based locked up and only accessible by authorized personnel. To open the iron door it requires the player to place two key password papers in the hopper. Once entering, there will be a button inside to close the door. This means the passwords are only required when entering the building.
Identity Security Card V2
This machine works similar to the other secured door but one difference is that the password can be retrieved from the dropper after you've used the button to open the door.
Vending Machine (No Payment)
Set up a free to use vending machine. Use the arrow to select the block which you want to retrieve and then press the button to get it.
Animal Cooker 3000
The idea is awesome. Free cooked meals. But I couldn't get it to work entirely. You are supposed to put a spawn egg in the chest on the right and then pull the lever on the wall to release the animal in the cooking machine. This all works fine but I never seem to retrieve the steak. If you do get it to work, please let us know in the comments!
Item Frame Lock Door Systems
The four item frames on the left are just for demonstration and to show you the code you need to open the iron door, don't use these! Instead use the item frames and arrows on the right wall to open the iron door. This is a basic but very effective setup to make sure only you have access to your base and not some unwelcome intruders.
Infinite Iron Farm
Is it cruel? Most certainly. Is it an effective way to get iron ingots? Oh yes! It's a really simple setup with iron golems on the top of the machine which automatically drop into some lava when spawning. (If you wanna stop the cruelty or if it lags too much, use the diamond pickaxe to destroy the spawners!)
Epic Farming Systems
This is one of those machines which probably would put loads of people out of work if it existed in real life in the early 1800s. It's genius though. Press one button and automatically harvest all your fields and have all the crops placed in a chest.
Button Lock Door Systems
Four numbers are required to open the door. There doesn't seem to be a reset button, so I suppose you will have to add that by yourself somehow!
Super Awesome Wardrobe Room
Pick among several different armors, step into the wardrobe and press the button to automatically put the gear on.
Place an item in the dropper, pull the lever and it will travel to the top.
Purchase golden apples by placing emeralds into the hopper.