As I have a fix for the missed reverse problem that Defender players sometimes suffer from I want to make the solution available to anyone building a Defender game based on a MAME system.
I can offer a USB encoder with either 18 inputs or 24 inputs, and using MAME standard keys or my modified keys (ALT,CTRL not used). Encoders have a micro-usb socket.
But I don't want to get into the business of selling general purpose keyboard encoders, So email me if you are interested and let me know what inputs you need. If you are doing something interesting like Defender + Tempest or Defender +Missile Command I'll be able to incorporate those controls too !
I use dupont connectors at the encoder and solder or dupont at the controls. I can supply the wires for that set-up. Alternatively I can supply the encoder with screw terminals and nothing else ( you could find your own eg wires with quick disconnects ).
£25 18input encoder with dupont headers.
£27 24input encoder with dupont headers.
50p per input. Wires x2, Dupont female to bare end for soldering.
£28 18input encoder with screw headers.
£30 24input encoder with screw headers.