Would this controller work with Picade?

http://www.ebay.co.uk/itm/Zero-Delay-Arcade-Game-Controller-USB-Joystick-for-MAME-Raspberry-Pi-1-2-3-AC489-/311755635195?hash=item48961579fb:g:6SsAAOSwpkFY6Fa8

Might sound like a silly question but forgive me , Im very new to Picade and electronics etc. If I bought this, and put it together, made a little box for it etc, would it work as a second controller for 2 player games ie for play on the same screen, if I plugged it into the usb port on the raspberry pi inside the Picade?

I suspect it would. It will masquerade as a standard USB HID device. How easy it is to set up depends if it emulates a keyboard or gamepad, though.

I don’t believe EmulationStation differentiates between multiple keyboards, but you can certainly make Picade (PCB) pretend to be a gamepad.

Happy to help you get it up and running if you post your experience here ;)