This add-on (also named “hat” in the RP world) is a double-sided PCB that sits on top of the Pi’s GPIO pins and turns the tiny computer into a fully functional device that can be used inside arcade cabinets or with a supergun setup.
The new Jamma hat eliminates the need for a separate power adapter as the host setup’s PSU now serves as the main power source for the Pi. On the video side of things, RGB signal, without any conversion, will be directly fed into the arcade monitor (or any RGB monitor). The most exciting feature, for me personally, is the ability to use Neo-Geo controllers (or a custom-made stick with a db-15 connector) through my H.A.S, instead of going down the on-board USB ports route.
I really admire the plug-and-play nature of such a product; it simply turns the RP into an arcade board that can be conveniently plugged/added into an existing Jamma setup. The Jamma RGB-Pi hat will set you back ~55$. That’s not too bad of a deal, specially that RGB-Pi’s own custom image runs arcade games in their native resolutions and refresh rates.
PS: The Jamma RGB-Pi is only available on RGB-Pi‘s official website; in order to buy one the user must first fill a form, then he/she will get contacted by email to complete the purchase.
Check out the installation instructions: https://github.com/mortaca/RGB-Pi/blob/master/jamma.md
RGB-Pi’s official website: http://www.rgb-pi.com/