Here's something I've been pondering for a while so I thought I'd throw it out there to the experts to see if it's feasible:
What I want to do is make an Arduino circuit that can play specific sound samples and take other actions when it detects certain EPROM addresses being accessed on another circuit board, in my case older coin operated arcade game boards (80's/90's era, like Pacman and such). What I'm wanting to do is be able to add additional sound effects, possible speech and other things to games that don't normally have them, having it cued by things such as the game displaying specific graphics like the player's character exploding, getting punched in the face, etc. I'm thinking that perhaps I could have it detect when the address pins of the graphics EPROM go high in the order to call up each of the graphics I want to cue off of.
Example: For the game Double Dragon = Player get's punched in the face - original game program calls up graphics image of character reacting to it - Arduino detects that address being accessed on that graphics EPROM and plays an audio clip like swearing, yelling "Ow!", etc.
Sound plausible? I'm hardly an electronics or Arduino genius so I'm open to the idea that I have NO idea what I'm talking about and it couldn't work the way I'm thinking.