Blog: Prototyping Accessible Green Tech in Garden Lab Whispers Grow

Our Garden Lab Whispers Grow project is now well underway! We have been experimenting more with mud batteries and macroscopes, exploring themes of accessibility and nature connectedness. 

After an exciting start with mud batteries and macroscopes, our team of collaborators met again to do some more hands-on exploration! Our team includes KWMC producers, Wales-based DIY tech artist Paul Granjon, accessibility advocate/disabled designer Ruth Hennell, local green groups, and local disabled creatives Oliver Woods and Daisy Hvnter.

We kicked off the session by revisiting the mud batteries at Springfield Community Allotments. Mud batteries capture the electricity produced by microbes living in the soil. They are a great way of making people aware of the life going on under their feet at all times. This time, we began with potting some humble weeds – often disregarded by gardeners as a nuisance. However, even a weed can create power with a little help…

Creating a Mud Battery:  

To make the mud battery, we planted the weeds in pots of soil. Then, some copper and zinc-plated electrodes were added to the pot, creating a chemical reaction which produces electricity. Bacteria in the soil settle on the electrodes, bringing more power to the battery. The weed in the pot helps keeping the soil healthy and nutritious for the microbes. You might remember from our previous blog that this reaction generated enough power to turn on a small LED light.  Here’s a video of artist Paul Granjon explaining how make one yourself:

However, the power created by the mud battery is low and it fades when too much is required from the microbes. To allow the microbes to “rest”, we can power the circuit at regular intervals instead. We tried linking multiple batteries together, creating a harvesting circuit that stores the electricity from the microbes until there is enough to flash a little red LED light. We learned that while one plant pot can create about 0.5 volts, five plants joined together can create around 2-3 volts. 

This voltage can be represented through sound. We experimented again with a speaker (powered by a separate standard battery) which generated sound depending on the voltage reading. The sound was a quiet crackly noise when the voltage was low and got louder when the voltage was higher. This crackle can be re-coded to any sound, so one volt could be a chicken clucking, while two volts is a cow mooing! 

Mud Battery Prototyping: 

We loved that the microbes cannot continually create electricity – they need to rest, as we all do, particularly those of us with chronic illnesses. Inspired by this, Ruth has been working on sketches and prototypes for a plant bed in the shape of a human bed. We are imagining having them activated by a timer switch which plays a little melody for a few minutes before the microbes rest again. 

Meanwhile, Oliver has been working on a 3D printed controller for the mud battery’s circuit board to sit inside. The design is based on photos of soil microbes, which “look like a wotsit with little wiggly tails”!

This idea was developed further with young people at Springfield Community Allotments on 30th October. We are excited to share more information about this soon.

Macroscope Prototyping: 

Alongside our mud batteries, we have also been playing with macroscope cameras (not to be confused with a microscope, which captures atoms and molecules. Instead, a macroscope captures extreme close-ups of anything that could be seen with the naked eye).

We have been thinking of how to attach it to a mobility aid and adding a joystick control so it can be controlled from the top of the aid. This would enable people with mobility disabilities to view different perspectives without necessarily moving their physical bodies. Paul has been experimenting with using a Nintendo Wii remote for controlling a WiFi macroscope. We explored the design together at The Factory on 8th November.

Meanwhile, Ruth has been thinking of a snail-shaped case for the macroscope, inspired by the ‘snails eye view’ she gets when she lies down on her mat. Paul mentioned that we could make a mobile remote-controlled snail macroscope. Ruth loved the idea of sending out a robotic snail out to explore on her behalf when she is stuck in her flat with fatigue or pain.

We have be prototyping this further at The Factory using a toy remote-controlled car!


Garden Lab Whispers Grow is funded by Bristol + Bath Creative R+D Grounding Technologies and supported by Impetus. To carry out the project, KWMC is collaborating with Paul Granjon, Ruth Hennell, local green groups, and accessibility advisors. Paul is a Wales-based artist with a background in DIY technology and Ruth is a Bristol-based disabled interdisciplinary designer and accessibility advocate. Together, we are designing a series of “garden lab” experiments in the allotment and beyond, looking into how to grow more caring relationships with nature and inclusive processes for climate action. This project is supporting KWMC’s aims for setting up future long-term citizen science programmes in the neighbourhood. 

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