The Dice-O-Matic is a giant rube-goldberg random number generator used on Games-By-Email in lieu of a cheaper, less-physical, less-cool software dice-roller.
The Dice-O-Matic is 7 feet tall, 18 inches wide and 18 inches deep. It has an aluminum frame covered with Plexiglas panels. A 6×4 inch square Plexiglas tube runs vertically up the middle almost the entire height. Inside this tube a bucket elevator carries dice from a hopper at the bottom, past a camera, and tosses them onto a ramp at the top. The ramp spirals down between the tube and the outer walls. The camera and synchronizing disk are near the top, the computer, relay board, elevator motor and power supplies are at the bottom.
The dice start the cycle at the top of the ramp, toward the rear of the machine. The ramp is comprised of ten steps, each at about a 20 degree incline, with a right hand thread through two and a half spirals. Two layers of cloth covered foam (car headliner) keep the noise down. Felt covered foam quarter-obelisks are at each corner, sewn to the side padding. It took a few tries to get the pitch just right. Too shallow and the dice stopped tumbling, too steep and they would start banging against the Plexiglas. Now they roll very well, sometimes stopping and then getting knocked back into the stream. Perfect.
The hopper at the bottom of the ramp is pure seething violence. I am sure there is a better way to load the dice into the buckets (vibrating tables and all that) but not in the budget and footprint I have. Instead, buckets come up through the bottom of the hopper, smashing their way through the accumulated pile of dice and scooping some up. It is rather hard on the dice, much of the paint gets chipped from the edges of the pips. The buckets are close enough together that dice cannot slip through the bottom.
As Schneier notes, "As someone who has designed random number generators professionally, I find this to be an overly complex hardware solution to a relatively straightforward software problem. But the sheer beauty of the machine cannot be denied."
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