Summary

Origional project by Oscar Fehlberg: https://grabcad.com/library/olympus-xa-external-flash-cord-1

This mod turns the Olympus A16 (or A11) flash into a simple hotshoe flash with cable using type-c or PC sync port. The flash mount also houses a DIY PC-port-to-type-c converter.
There are 5 spring-loaded connectors on the TT350 flash mount, only centered one is needed. Other 4 connector heads and springs can be salvaged for spring loaded connectors in the mounts.
On the flash mount, A needle hole needed to the punched through the hot shoe mount housing to fit a small needle for turning on the flash (4th pic, next to top-left screw)

BOM:
1x Godox TT350 flash hotshoe mount replacement
2x Type-c usb female connector
2x PC sync port female connector
4x M3 x 2mm grub screw
1x M3.5 x 12mm screw
1x M3.5 nut

(for PC-port-to-type-c converter:
1x PC sync port male connector
1x Type-c usb female connector)

Additional:
Soldering gun
Epoxy glue