If you've been 3D printing for a while, you might have heard of Klipper. This custom firmware improves many 3D printers, but does take some work to install.

Created and maintained by Gina Häußge, OctoPrint allows you to turn an old computer (or more commonly a small ARM board like the Raspberry Pi or BeagleBone) into a network-accessible control ...

But while the Raspberry Pi is more than capable of controlling a 3D printer in real-time, there has always been some debate about its suitability for slicing STL files.