Self-sustaining robots can do just about anything on their own for days at a time. They can even ingest biomass for energy. The problem is that until now, they couldn't do anything with the waste from that energy.
That's why researchers at the Bristol Robotics Lab in England developed an artificial gut for self-sustaining robots to excrete those biomass wastes. Called the Ecobot III, this system allows it to survive for up to seven days, feeding and "watering" itself without human intervention. It even expels its waste into a litter tray once every 24 hours.
Here's how it works:
1.The robot is fed a nutrient-filled "sewage" with plenty of minerals, salts, and vitamins.
2.The solution goes into one of 48 microbial fuel cells.
3.The solution metabolizes and gives off hydrogen atoms, which generate an electrical current, as well as water.
4.That waste is recycled through the system several times to extract as much energy from it as possible, before it is excreted.
Even after this exhausting process, recycling included, the fuel cells in the Ecobot III can only extract one percent of the chemical energy available in the food it ingests.
And the waste itself is pretty nasty stuff, as you can imagine. Chris Melhuish is the director of the British lab that is conducting this research. He told New Scientist that the generic term "waste" doesn't quite capture it right. "Diarrhea-bot would be more appropriate," Melhuish admits. "It's not exactly knocking out rabbit pellets."
But researchers don't have any plans to change what that waste looks like. Instead, the next step is to explore how the robot will cope with a heartier, perhaps protein and fiber-enriched meal, by which I mean flies.