> I'm particularly interested in what types of machines
More important is to look at who's got owning shares in those machines.....
In the perfect world, we'd have open source machines that all enter voites into a public blockchain/ledger and you'd get a private key you could verify your vote with. Optical sounds awesome. But good luck with that. The fraud just seems to swing back and forth from left to right every X years instead. It's madness.
My claim is just a bet right now. But it's one I'm willing to put money on IF they actually do a national investigation, which I'm not confident will happen.