I have designed an Arduino based pinball controller for use in Williams games from System6 to System11c.
This board will replace all CPU, Power driver and Music/Speech related boards - an interface for hardware extensions is also present.
At the moment this board cannot be used as a pure replacement as it cannot use the original EPROM software, instead it is meant for people who want to program their own games or add some hardware toys. I have therefore programmed some kind of pinball operating system which takes care of the hardware related stuff and offers an API for the game programmer to work with.
The board is quite cheap (well below 100€) and has no special components like FPGAs on it, so it is quite easy to build it by yourself.
There's a catch of course: I don't want to earn money with this project, which means I'm not going to sell boards or anything else to you, so you don't have much choice except of building it by yourself. However I put all the necessary data to my project page at GitHub, together with a lot of information to make it as easy as possible.
It's still a lot of work to do the code for a new game and I'm some how fed up with doing it all by myself. Therefore my hope is to establish a small community of people who have fun designing new game rules and who just needed a base to start from.
So, if you are interested in this project, please give me some feedback.
The photo below shows the APC in my Pinbot