EcoBot Turns Waste Into Power

Cabe Atwell

January 28, 2014

3 Min Read
EcoBot Turns Waste Into Power

As robot technology advances, one important area of common concern is how to power these bots. The same is true for many different areas of technology. Exoskeleton suits are under development, and some already work great, but keeping these suits powered for more than five minutes seems to be a big drawback. The easiest approach is to increase the battery size or the number of batteries supplying the system. However, this can weigh down bots and exoskeletons and increase the amount of energy needed to power the system. Overall, this defeats the purpose of adding the batteries in the first place.

It is clear that a new method of energy is needed to power robots. Scientists and researchers have been working to develop robots that can harvest energy to recharge their batteries. Such robots should be able to last longer in threatening environments or in areas where little human care can be given. One such robot currently being tested is the EcoBot.

Developed by Chris Melhuish and a team of researchers at the Bristol Robotics Lab in the UK, the EcoBot has been built to derive energy from organic matter, including flies, old vegetables, or even human waste. It was originally developed and tested by feeding it flies. Unfortunately, to get flies lured into the bot, it needed to smell like sewage. A bacterial enzyme inside the original version would break down the fly's chitin exoskeleton. Sugar from the chitin would be metabolized to release electrons. Sulphides would combine with electrons, migrate to the anode, and release the electrons to create a potential difference between the anode and the cathode.

The bot has since been upgraded to include a biochemical reactor, known as a microbial fuel cell. This breaks down electrons in a very similar manner. However, experiments have shown that the EcoBot's electric motor pumps are prone to blockages and breakdowns.

As a result, the researchers have developed a 3D-printed, shape-shifting, heart-like pump to prevent buildup and blockages. "We've used smart materials that contract a bit like muscles do to compress the body of a far simpler pump," engineer Peter Walters of the Centre for Fine Print Research in Bristol told New Scientist.

The pump uses nickel-titanium fibers and compressible silicon to create a heart-like pumping system when current is applied. The system leaves deposits and rock-like structures at the bottom to prevent clogging.

Using sewage and organic waste is a great idea for powering robots. However, much more research and advancement is needed before this can be a practical way to harvest energy.

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About the Author(s)

Cabe Atwell

Cabe is an electrical engineer, machinist, maker, cartoonist, and author with 25 years’ experience. When not designing/building, he creates a steady stream of projects and content in the media world at element14,, MAKE ─ among others. His most recent book is “Essential 555 IC: Design, Configure, and Create Clever Circuits.

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