In 2016-17 I worked with bio-engineer Michka Melo on microbial fuel cells, also known as mud batteries. We conducted various experiments in my studio and in the FabLab at Cardiff Metropolitan University, attempting to make an open source design for use in art and design, education, diy off-grid applications. We presented our result in the V&A’s Digital Design Festival in September 2017.

You can find an account of our experiments here.

 

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In 2018 I was commissioned for a new robotic art installation for the exhibition Y Las Cosas Que Hacemos (and the things we make) in Bilbao, Spain. I made 11 Mudbots, small mobile robots powered by microbial fuel cells (MFCs), loosely inspired by the dung beetle. The MFCs in the Mudbots did not work for long and the installation relied on human power for most of the duration of the exhibition. More info here.

 

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Slightly disgruntled by the experience, I stored the Mudbots and focused on other matters for a couple of years. In 2021 I was contacted by Mexican product designer Tony Gutierrez who had found out about the Mudbots. Toni had developed Mosby, a very elegant design for MFCs that includes living moss. The moss contributes to a healthy bacterial population. We agreed to share best practice of Tony’s long-lasting MFC units and my electronic designs towards an open-source recipe for easy to make and maintain mud batteries.

 

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With my interest in MFCs renewed, I received a small grant from Cardiff School of Art and Design towards further experiments with plant MFCs using bryophytes (moss), taking inspiration from Mosby and from experiments conducted by Paolo Bombelli in Cambridge. The grant was also used for designing an electricity harvesting module with an electronic engineer. I presented the mixed results of this new wave of experiments at the Beyond conference in Cardiff in autumn 2022, see poster here.

 

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I am now working on a new wave of MFCs, using a simpler and easier to maintain design with copper-zinc electrodes, that so far is giving good results. In collaboration with artist Harun Morrison we will implement in March 2023 an installation at Goldsmith University London. Located in a garden on campus, Singing Compost will convert the electrical activity of MFCs embedded in the soil into sound.

 

Tech note June 2023

We found out after installing the Singing Compost that the copper and zinc electrodes we used generate a current due to their electro-chemical properties (the oxidation of zinc occurs at the anode, while the reduction of copper ions happens at the cathode). It is possible that electrogenic bacterial populations close to the electrodes contribute to the electrical output, but most electricity harvested is from the copper-zinc oxydo-reduction reaction, with moist soil acting as the electrolyte. This system is referred to as an Earth Battery.

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My long time friend and brilliant sci-artist Antony Hall is also working on MFCs at the moment, check his work here, a collaboration is in the pipeline.