Adapter for Atari/Sega joysticks on Apple ][ / Franklin ACE 1000
This is a slight reworking of Tor Arne Hustvedt's "Apple IIe digital joystick adaptor for using Kempston/Atari/Amiga digital joysticks on an Apple IIe", available at https://www.pcbway.com/project/shareproject/Apple_IIe_digital_joystick_adaptor_for_using_Kempston_SEGA_Atari_Amiga_digital_joysticks_on_an_Apple_IIe.html
The schematic has been recreated from the board file, and the BC558 PNP transistors have been replaced with 2N3906 transistors (which seem to be more readily available).
STL files for a 3d-printed case are in the stl/ directory.
The resulting board works perfectly on a Franklin ACE 1000 using an Apple //e-to-][+ game port adapter purchased from console5 (https://console5.com/store/byteboosters-9-pin-to-dip-16-pin-joystick-adapter-for-apple-ii-plus.html). As it appears to be out of stock, I'll trace out the connections at some point and publish a DIY clone.