The "gastrobot" has arrived: the world's first robot that eats and digests to generate its own power and that may eventually produce robo-poop. The hungry robot, built at the University of South Florida in Tampa and dubbed Gastronome, is one meter long and rolls on 12 wheels. Gastronome is powered by a microbial fuel cell filled with E. coli bacteria. So far it only ingests sugar; as the bacteria break down glucose molecules, electrons are released and captured to charge a battery, which powers the motor. The contraption could run on vegetation-or meat, for maximum energy-but would eventually become constipated: The complicated process of waste elimination hasn't been perfected. Inventor Stuart Wilkinson, an associate professor of mechanical engineering, says one eventual commercial use could be a robotic lawn mower that eats the clippings for power.

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