In this Instructable I will be teaching you how to make a simple redstone machine that smelts/cooks things for you. All you need to do is put the item you want to smelt/cook in the first chest, then wait and take it out of the second chest! Note: This will work on all platforms of Minecraft, including MCPE :D
Step 1: Let's Begin
First, simply dig a hole with a length of 5 blocks, a width of 4 blocks and a depth. Look at the picture for more of an idea.
Step 2: Building the Internals (Part 1)
Place a dropper (facing up) where the picture shows. Crouch and connect 2 hoppers to the dropper. Place a furnace on top of the far left hopper.
Step 3: Building the Internals (Part 2)
Add a hopper on top of the furnace (while crouching), and then place a chest on top. On the right side place a block, then place 2 hoppers on top of each other (facing upwards, and crouch while doing this), place a chest, and you are almost done!
Step 4: The Redstone
Now for the hard part. First extend your hole a little, use the picture to help. Place a comparator facing out from the bottom dropper. Place a repeater in front, place another comparator in front of the repeater, but click/tap this one to make the little front torch turn on. Put some redstone dust in front of this comparator, beside it, diagonally, and next to the repeater. Once this is done, place another repeater going into the block below the droppers. This is really hard to explain, so please look at the pictures to help.
Step 5: The Redstone (again...)
Build a platform on top of the circuit you just made (look at the pics) and build the circuit again, the comparator coming out of the dropper. LOOK AT THE SECOND PICTURE, IT IS VERY IMPORTANT. Yay, you are almost finished!
Step 6: Coal
Simply add heaps of coal to the furnace now. In the picture I used 64 coal blocks.
Step 7: Decoration
Now just add blocks of your choice to cover up the insides. You can now put signs above the chests saying 'In' and 'Out' if you want.
Step 8: Finished!
Please feel free to comment and stuff! But before you try it, read this: If you put something in the chest that is unsmeltable, it will jam up and the only way to get rid of the jam is to break one block in the floor and take the items out of the furnace. Have fun with it and comment with a screenshot of it! :D Enjoy!