A Self-Made Machine

Fulfilling the dream of self-replicating machines

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More than 50 years ago, computer pioneer John von Neumann dreamed up a self-reproducing machine. It would mine its own ore, and smelt it into metal ingots. Then it would machine the ingots into parts, and assemble them, into a copy of itself. During the 1980s, nanotechnology evangelists worked out the same idea on a much smaller scale. Critics envisioned a horror scenario, of molecule-size bots, reducing the entire world to a "gray goo."

Today there's RepRap, short for "replicating rapid-prototyper." RepRap isn't a von Neumann-style omnivore, but rather, a parasite. It doesn't harvest its own materials, like gray goo, or von Neumann’s idealized machines. But also unlike them, it's entirely real. To reproduce, it needs a ready supply of metal rods, machine screws, stepper motors, microcontroller boards, and meltable plastic filament. And geeks.