The WaveShare CM4-IO-POE-BOX-B is one of my favorite ways of deploying a Raspberry Pi and it already comes with a lot of the I/O options that I frequently need. It even accommodates some Raspberry Pi hats.
But if you want to stack multiple hats, include additional break-out boards (e.g. for radio connectivity), and install several external connectors, then you quickly end up with an unmanageable tangle of wires and cannot close the original case.
This model provides an alternative cover. It has space for two small PCBs that can be tucked away to the side, it has openings for up to four standard keystone inserts, and it has a big hole for a 22mm diameter socket (e.g. an XLR socket for DMX512 connectivity using the built-in RS485 port).
I find that RJ45 keystones offer a lot of flexibility to bring an assortment of inputs and outputs to the outside. But the beauty of keystones is that you can easily customize the type of connectors that you want for your own application.
You can of course edit the included OpenSCAD file, if you don't need all of these features (e.g. the big 22mm hole). In fact, all of the dimensions can easily be adjusted in the file, if you discover you need a bigger or a smaller enclosure.
Prints with pretty much any filament. Use four square captive nuts and 15mm M3 screws to attach the new cover.
The author marked this model as their own original creation.