I'm not the first one to have thought of this and there are many ideas as to how to do it. Presented below is my take on an ST-4 compatible autoguiding interface. It plugs into the Pi's 40 pin I/O connector and sticks out of the case so as to allow the cable to connect from the guide port on your mount to the Pi. I've also added a DSLR trigger too.
I've uploaded the board to Oshpark so that you can order one (well, 3 really). The BOM is trivial and the opto chips are nothing special.

Below are the Eagle files.
RPi_ST-4_Opto_Interface.brd
RPi_ST-4_Opto_Interface.sch
Which 3D rendering software did you use?
ReplyDeleteYou say the BOM is trivial, but I don't know what components you used. Unless I'm just missing something.
ReplyDeleteRead the schematic. It's a quad opto-isolator and a single opto-isolator and a few 100r resistors.
ReplyDeleteThe rendering software is Eagle3D. It's a free ULP script from somewhere in Germany. I've had it forever.
IIRC the current Eagle has a built in renderer.
Looks awesome. Which driver is used for this?
ReplyDeleteAlso: can you put up the BOM anyway?