9.6 hours · 1:39pm Mar 13th, 2017
That's how much battery life my laptop on Minecraft will have. Lemme explain:
Large chests have a 6x9 space, each able to hold a stack of items. When you smelt an item, no matter what it is as long as it can be smelted, it will take 10 seconds to smelt it. So, I need a small chest for fuel which I'll use charcoal and a large chest for oak wood logs.
6x9 stacks of 64 oak wood logs taking 10 each to smelt would be 6x9x64x10 = 34,560 seconds.
To get this into hours, I divided by 60 twice. 34,560 seconds divided by 60 is 576 minutes. 576 minutes divided by 60 is 9.6 hours.
There will be power going into the hoppers that go into the furnace to keep the charcoal and logs in the chest while the laptop is off, but when turned on, they'll no longer be powered and the furnace will start cooking. I will have to work out something so that only one charcoal and log are used at once. If I let them just flow in, they'll cook while the laptop is off, thus killing the battery.
To have the battery be able to turn off the laptop, there will be a comparator coming from the furnace and into a block with a redstone torch on top. When nothing's being cooked, the comparator will shut off, the torch will turn on and will force the laptop to shut off and keep it off.
Neat, huh?
Pretty cool! I've always loved redstone circuitry. I haven't gone THAT deep into it, but I have a lot of contraptions in my Minecraft worlds (mostly secret-not-so-secret doors). I haven't been on in a while though. It's kind of sad, really, but I haven't had the same drive to build redstone stuff like I used to.
4455635 The battery isn't really deep, it's just using comparator mechanics from a furnace until everything's been cooked and the power goes off.
Although, the touchpad for it is going to be pretty hectic. Ya. I made a downwards selector with pistons.
It's an area (9x13) with iron weighted pressure plates on top. Below this is redstone dust over a 9x13 area. Under the glowstone are sticky pistons facing down and they are placed every other block. The first row of 7 pistons has a redstone block on the face, the next row has two slimeblocks coming from the faces of the pistons then redstone blocks, then the next row has four slimeblocks and a redstone block, then the last row has 6 slimeblocks and a restone block.
I used the weighted pressure plates because when stepped on, they power only one spot of redstone. So every other plate will activate a piston. Those then go to power their lines which will allow you to move the cursor on the screen which I have not gotten to yet.
There are also the right and left click buttons. I have done nothing with the left click button so far but I've got an idea how to get the right clicker to work.
You see, when you activate any one of the pistons on the touch pad they invert a redstone torch. Each of those pistons wil invert one and they all connect to one line and to get that line to turn off, all the redstone torches will need to be inverted. This right click button simply activates all the redstone on top of the glowstone, which lags the game a bit.
The line then turns of but then back on again and the line goes into a facing up sticky piston with a block on top, a repeater coming out of that block on one tick and into another block which has a facing up stick piston beneath. What happens is the second sticky piston only gets a 1 tick pulse of power so it pushes up its block but doesn't pull it back down. This piston segment is a t-flip-flop. You give it a pulse of power it turn on, give another pulse it turns off. From there I will have to think of what the right clock button will do and how to do it.
Now that's just the touch pad! Would you like me to explain how I power the 40 high by 74 wide redstone lamp screen by 2x2 segments?
4455877 No, I know the battery isn't that crazy, but the rest of it sounds freakin' bonkers!
I had some trouble following that, so no, please don't explain any more of it. I would love to talk about it if we were looking at it and playing the game and stuff, but trying to imagine it from text on a screen is almost painful. I would ask if I could take a look at it and play Minecraft with you, but my PS3 was stolen some time back. 
I still have my PS4, but that won't do a lot of good, now will it? 