This project provides computer control for the Yaesu G5500 rotator without the need for their GS232 controller. The interface connects any Raspberry Pi to the 8 pin DIN connector on the rear panel using a small amount of auxiliary circuitry. Look through the document G5500pi.pdf for full details. To give it a try download the software bundle G5500pi.tgz, version 1.1.
73, Elwood, WB0OEW
Here are a few snapshots of my prototype connected to a Raspberry Pi Zero W. Click for larger size.