Talk:Tutorials/Storage minecarts

Loader Design C doesn't work in 1.14

--93.36.192.138 15:38, 10 November 2019 (UTC)Insane

Unloader design C doesn't work at all - I think there is an error in it. The lower of the two repeaters should actually be a redstone comparator.

Maximally Robust Item Loader
Here is an item loader design I've come up with that is robust against various circumstances that might cause other loaders to jam:


 * non-empty incoming minecarts
 * hopper minecarts
 * non-cargo minecarts
 * a clutter of small item stacks to load

In addition, minecarts are filled as much as possible, and the cart is not sent off unless one of the following criteria is met:


 * The cart is genuinely full.
 * The cart is out of empty slots, and the items to load don't match the partially filled ones.
 * The loader is out of items to load (optional, see below).

The key idea is to have two fill lines: A primary fill line and an overflow fill line. If at any time there is an item in the overflow line, it indicats a full cart, causing the minecart to be sent off. At the same time, the overflow line is blocked to prevent it from clogging up. The overflow line automatically empties into the next cart, resetting the mechanism even before the cart has time to bounce back, and loading resumes.

The main fill line is also monitored, and any incoming minecart sent back immediately if there are no items to load (except possibly the overflow, which will empty ioto the cart at this occasion). This is optional; to have carts wait for more items to load, just omit the rightmost two columns as well as the redstone wire at the center of the bottom layer. Alternatively, the behaviour can be temporarily switched off by powering the block labeled "A", e.g. via a lever or other circuitry.

(Note: Do not place a wide chest across the top hoppers. While it may seem tempting, it will break the mechanism.)

Of course even a near-ideal design come with a few caveats:


 * If a minecart comes in with no empty slots and can't accept the item in the overflow line, the cart is rejected even if items in the main fill line would match. (I guess theoretically this could even happen if items in the overflow and main fill lines compete for the only empty slot, but I'm not seeing this in practice. - Edit: This does indeed happen.)
 * The overflow only kicks in as soon as the main fill line bottom hopper has filled up. Therefore, the loader doesn't send off the minecart until it has a hopper's worth of more items to load.

The latter issue could probably be mitigated (though not reliably eliminated) by additionally monitoring the main fill line bottom hopper for a power-2-or-greater fill level, and using this as an alternative signal to stop the loading process and send off the cart; however, such a mechanism might be difficult to fit in alongside the "out of items to load" detection circuitry, and would still fail for a clutter of small stacks.

Tested in Java Edition 1.16.1.

CLipka60628 (talk) 10:24, 17 July 2020 (UTC) Minor edit: CLipka60628 (talk) 11:06, 17 July 2020 (UTC)

Variant Design
Here's a variant of the above design that reduces the number of excess items required to detect that a minecart is full. In this variant, 23 stackable items or 1 unstackable item will suffice. The overflow detection still has its place though, as it prevents the loader from clogging up with small stacks of different type.

As a drawback, the "send cart home if out of items to load" mechanism cannot be temporarily suspended in this variant; powering the corresponding block would "spill" over to other subsystems and mess them up.

CLipka60628 (talk) 11:26, 17 July 2020 (UTC)