Is there a way to break blocks with a redstone/piston system and then pick them up with a hopper in vanilla Minecraft. I want to make an automatic cobblestone breaker.
I know that I can break sand, I want to know how to break stone.
Not possible in vanilla. For automatization you should use some mods, they are just for this.
If you want really a lot of cobblestone vanilla way, just make yourself Effi 5 diamond pickaxe and place beacon with Haste 2 , then you can break mountains in seconds :)
If you do skyblock, automatic grinding of stone is maybe useful, but can be considered as "cheating" :)
you can use command blocks. place a redstone torch under the block you want to break and a command block above. then the command is:
/setblock <x> <y> <z> minecraft:air 0 destroy
in your case it will be:
/setblock 0 0 -1 minecraft:air 0 destroy
other than that there is no vanilla way. (this is also not very vanilla)
to pick it up by a hopper place the torce on a wall under it and place the hopper at least 2 blocks under the cobble to make shure that you don't power the hopper
Here is a proof-of-concept video, illustrating a system using TNT. The cobble is generated and blown up by TNT; and then transported by water to (presumably) a hopper. There are other ways to achieve the desired effect -such as using creepers/withers/etc (through a monster spawner or darkened room) - which could be done, for example, by using creepers and ocelots with directing corridors, to get the creeper to where you wanted him to go.
If you're looking for an easy way, just get a whole bunch of gunpowder and make loads of TNT. Otherwise, I'd suggest trying the "creeper and ocelot" method.
It is impossible to break blocks like cobblestone using only redstone or pistons. However, there are several mobs such as the Wither, Ghast, and the Creeper that can break blocks. My suggestion for making a block breaking system would be to use these creatures of mass destruction.
One way to do this wold be to have an observer block facing down at the cobblestone which triggers a piston to push the cobblestone when it appears, you have pistons further down that push these lines of cobblestone into a big stockpile, there you can mine it or blow it up.