IDEAS FOR GOODThe crQlr Awards, a global program celebrating projects and ideas that design for a circular economy, was launched in 2021 as Japan’s first award dedicated to circular design. One of the special award-winning projects for crQlr Awards 2024 is the “‘Return to the soil’ circular sensor“.
“Return to the soil” circular sensor
The “Return to the soil” circular sensor is an IoT device made primarily from plant-derived cellulose nanofibre, designed to decompose naturally with the help of pill bugs and other living creatures in the soil.
IoT sensors, which detect and transmit environmental data such as temperature, humidity, and soil moisture, are increasingly being used in agriculture, environmental conservation, and urban management. For example, in agriculture, soil moisture sensors enable optimal irrigation, while temperature and humidity monitoring systems help predict pest outbreaks, leading to more efficient use of water and pesticides.
Similarly, in urban management, real-time environmental data collection is crucial in responding to extreme weather events like heatwaves and droughts, exacerbated by climate change. As the number of sensors deployed in the environment continues to rise, so does concern over the environmental impact of these electronic devices.
On the other hand, the increase in environmental burden caused by installing sensors in natural environments has emerged as a new challenge.
Electronic devices, including sensors, are developed with long-term stable operation in mind, so they are typically made from long-lasting materials such as plastic, copper, and silver. As a result, conventional electronic devices do not easily decompose in the environment and, if not properly collected, can become electronic waste that pollutes the environment.
Industrial and agricultural sensors are widely deployed, but retrieving them remains inefficient. Additionally, as sensors shrink and become more complex, collecting and manual disassembly become increasingly difficult. IoT sensors with wireless communication and batteries contain tightly bonded materials, complicating separation and increasing recycling costs.
The “Return to the soil” circular sensor addresses these challenges by redesigning sensor materials and structure. The sensor detects soil moisture by emitting heat, which is captured using a thermal camera, allowing remote monitoring of both the sensor’s location as well as soil moisture levels.
While many attempts have been made to develop biodegradable sensors, achieving both sensing and data transmission functions while ensuring biodegradability has been a significant technical hurdle. The “Return to the soil” circular sensor successfully balances these aspects through an innovative design which considers the full product lifetime.
The sensor’s materials consist solely of naturally occurring plant fibers, soil components, and natural oils, including cellulose nanofiber, paper, natural wax, and tin. By minimising chemical processing, the device can be broken down by organisms like pill-bugs, eventually decomposing into the soil like fallen leaves on the ground.
A vision for circular environmental monitoring
The research group led by Assistant Professor Takaaki Kasuga from Osaka University’s Institute of Scientific and Industrial Research (SANKEN) developed this sensor. These researchers describe it as a “deployable sensor” that can be installed in large numbers without contributing to long-term waste. Future applications include integrating fertiliser components into the sensors, creating a dual-purpose device that both monitors and enhances soil health, creating an important regenerative function to the sensors.
Cecilia Tham, one of the award judges, praised the project. “This project presents a well-thought-out approach to addressing the growing issue of electronic waste while achieving essential environmental monitoring. It holds great potential for applications in agriculture, conservation, and urban management. The ambitious vision of harmonising technology with natural ecosystems is both inspiring and impactful.”
Environmental data continues to be an increasingly critical metric for research about the effects of climate change on our world and is recently being used more for corporate sustainability KPIs. The “Return to the soil” circular sensor is an essential invention for society, preventing the creation of new environmental burdens at the very point where data is collected.
Originally published on IDEAS FOR GOOD.
[Reference] Research at Osaka University[Reference] “Return to the soil” circular sensor
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