A simple conveyor built system, and I got the idea from KaspersMC.
It's an inovative device, and it can be used however you want to use it.
I also built it above ground for you to see how it works, and the way the first piston works, you pretty much just copy that and do that over again to make it however long you need it to be.
I suck at redstone so this is a great improvement for me.