Functionality

The Plopper is a block that will pick up any items in its general vicinity that are about to despawn. It will do so at a set range, which is 2 by default, but can be changed by adding upgrades. Each upgrade will add 2 blocks to the range, with a maximum of 16 blocks in total (7 upgrades). The range affects all directions (north, south, east, west, up, and down) and is cubical. Here's an image showing a cross-section of the plopper's range (white is default, black is fully upgraded):

You can access the picked up items by rightclicking the block, or piping items out of the bottom. But do note, that you can only pull items out of the plopper, and not put any into it. It's not supposed to be a storage solution :)

Showcase

Here is a video showing off the block. The birch planks represent the area in which the plopper in the video can pick up the items (note that the items dropped outside of the range don't disappear with smoke particles).

As you can see, the block comes with a sound and particles. Both can be turned off via the configuration file.

Like previously mentioned, the plopper works with pipes (in this example, Itemducts from Thermal Expansion)! By default, you can only extract from the bottom of the block, but that's toggleable as well. (The lever is not required for the plopper)