The most intelligent, cheap and easy way is to use a Playstation pad hack. Hacking pads is inexpensive and easy, just soldering cables on the surface of the pcb. The great advantage of this is that you can use it with your PSX, your PS2, your PC (there are dozens of models of PSX to PC USB adaptors), and also Dreamcast (I have two adaptors called Magic Convertor). All of these adaptors work perfect, with all digital controls working and with no delay at all. I have two arcade control panels and I use them both together with PC and Dreamcast.