This design can be created to absolutely any size, creating just one cobblestone block every 2 seconds, or hundreds. For the purposes of this tutorial, all data will be for this design, which is 8 blocks long.
- 8 Block Breakers
- At least 8 Pneumatic Tubes
- 68 Glass Blocks (amount varies depending on size, any block will work)
- 2 Buckets of Water
- 2 Buckets of Lava
- 8 Red Alloy Wire
- 1 Timer
- Some sort of receiving block for the cobblestone to flow into, e.g. a Chest or an Energy Condenser. For the purposes of this tutorial, it is an Incinerator.
The Heart of the Machine
First things first, what makes this work are Block Breakers. These RedPower2 machines will, upon receiving a redstone pulse, break whatever block is in front of them and send it out the back. If there is Pneumatic tubing there, it will be automatically sent to an appropriate location via the tubes. If not, it will simply be ejected and dropped onto the ground. Place your eight block breakers in the ground, and make sure that they are in a straight line and are adjacent to one another, as pictured.
For the purposes of the tutorial, we use Glass blocks, so that we can see what is happening. However, this container can be made out of any block which prevents the flow of water
Place your desired blocks in a two-block-high rectangle, around your block breakers, as pictured.
Then place a line of your desired block above your block breakers such that there is one block of air between the breakers and your blocks.
Watch your Step!
Place eight blocks at either side of the breakers. These blocks are temporary, so that the water and lava can spread out, rather than dropping straight down. You will be breaking (and losing) them in a few moments, so choose something expendable, like Dirt.
Now, the number of Lava buckets you will need will vary depending on how long you want to make your cobblestone generator. For an 8 block long generator, like this one, you only need 2, but for a 16 block long generator, you will need 4 buckets. The reason is because, as pictured, lava only flows 3 blocks out from the source block, and doesn't form new source blocks, like water does. So, for this 8 block design, you have to place two separate lava source blocks to cover the entire machine. Of course, you could just go out and get 8 buckets of lava, instead, but it's up to you.
Then on the other side, just fill the entire thing up with water. Using two water buckets, you can create infinite source blocks by placing one bucket, the placing the other bucket two blocks away to create three source blocks. Fill your bucket from the middle of the three and repeat to fill as large an area as you desire. Your generator should now look as pictured to the right.
Now go Underground
...Because working above ground is too mainstream. You will want to dig out directly underneath your block breakers, then one block to the side, so you have a 2x2 tunnel underneath the whole generator, as pictured. It's probably best to dig under the water, rather than the lava for obvious reasons.
Then place your Pneumatic Tubes underneath your breakers...
Now get out your red alloy wires and place them on the ceiling directly next to your block breakers. If you did not know they could do that, now you do. They can also go on walls and between Microblocks and all kinds of cool places. Place your timer on the ceiling as well at either end of the wire... yes, the timer can go on the ceiling too. Don't worry about the breakers activating - the pneumatic tubes shouldn't be connected yet, so the breakers won't actually send the cobblestone anywhere, they'll just hold on to it.
You can also use Redstone Tubes, which acts as both Pneumatic Tubes and Red Alloy Wire in one package.
And to Finish it Off
...place any extra needed Pneumatic Tubes to connect the block breakers with your chest / condenser / incinerator of doom and the block breakers will automatically begin sending your cobblestone to its destination. I've found the best time to set the timer to varies greatly depending on lag, location, length, and probably a half-dozen other things. For example, this specific setup, in singleplayer, on this world, runs at 1.550. A 16 block-long one on the specific SMP server tested can only run at 2.250.