I have acquired a programmable coin acceptor! Turns out they're pretty cheap... hoping to make a fun project out of this for the next hacker camp
I don't think it'll work with plastic coins though, so I may need to find a source for metal non-money coins somewhere
@joepie91 washers might be a cheap solution, if you need to source them in bulk? You could spray paint them with a stencil, or even laser engrave, if you have access to that.
