World Download for my Smart Minecart Loader. In this download, I have two versions of the loader: the first is the most compact form and works for hopper minecarts. The second is a slightly modified version that works for chest minecarts.

In the video I walk through a couple smart minecart loaders and describe several fail cases. Then, I show how to make my smart minecart loader that improves upon previous smart minecart loaders. My final design does not use any pistons and is the most compact smart minecart loader I've seen.

Several modifications can be made to this design to suit your needs. One that has been asked for is if there is any way to have the minecart stay at the loader until you want it to leave or until you put more items in the input chest. The answer is yes, and all you need to do is put a lever (or any redstone input) on one of the two top yellow blocks behind the chest. This will force the gate to be closed until you want it to open again. Another solution is to simple remove the top circuit (comparator, repeater, torch coming from the chest). Then the only thing that will allow the minecart to leave the loader is if it has enough items in the minecart (based on the barrel).