General "guide"
http://www.playvectrex.com/vectech/controller.txt
Vectrex digital controller pcb drawn in Eagle. This is designed to fit NeoGeoX controller
http://atariage.com/forums/topic/232810-vectrex-digital-controller-eagle-pcb-files/
Adapter to buy for Sega controllers:
http://www.computernerdkev.heliohost.org/vecadapt/vecadapt.htm
Vectrex controller to USB adapter, With this adapter, you can use a Vectrex controller as an USB joystick.
https://www.raphnet-tech.com/products/vectrex_usb/index.php
Instruction for PSX to Vectrex
https://www.instructables.com/id/Modify-PSX-Controller-for-Vectrex-Games-Console/
DIY Vectrex Light Phaser
http://www.binarystarsoftware.com/?p=282
Vectrex Controller to USB HID Joystick
http://little-scale.blogspot.com/2015/08/made-with-teensy-2.html
PSX to Vectrex
http://www94.pair.com/jsoper/vec_psx_adap.html
Not Available anymore
PSX to vectrex
http://www.multigame.com/psx2vect.html
VECTREX <>PLAYSTATION 2 ADAPTER
http://broadcastzen.com/playstation_adapter.html