What it does
Demetro simplifies urban reforestation by improving the accuracy of plant mapping and tracking. Developed for projects like ForestaMi, it uses GPS and NFC to verify planting, monitor growth, and support collaboration between volunteers and institutions.
Your inspiration
We started from a simple observation: urban reforestation projects often face practical issues like measuring, mapping, tracking. While supporting initiatives like ForestaMi, we saw how volunteers and institutions struggled with complex tools and inconsistent data. We asked ourselves how we could make the process more accessible, accurate, and open. That’s when we hacked an odometer and began building a modular system combining analog mechanics and digital tracking. Demetro was born from the belief that better tools can empower people to take better care of the environment, together.
How it works
Demetro is a tool designed to support urban reforestation through a four-phase process. It begins with planning: using tools like QGIS or AutoCAD, experts create a digital map with precise coordinates and species information for each tree. This map is uploaded to uMap, exported as a CSV file, and loaded onto an SD card. On-site, the SD card is inserted into Demetro’s digital module. As the user walks, Demetro displays the direction and distance to the next planting point. Once the point is reached, a brake mechanism activates a spray to mark the spot. The device then resets and guides the user to the next point. During planting, Demetro shows the assigned species for each location. Users verify the match using NFC tags attached to the trees. These tags store species data and can be scanned later for monitoring. With a smartphone, anyone can report a plant’s health status, enabling accurate, collaborative, long-term tree tracking.
Design process
Demetro began as a university hacking project, inspired by the idea of repurposing an odometer to support urban reforestation. The first prototype was made from PVC tubes and PLA 3D-printed joints, using the wheel of a commercial measuring tool to track distances. The system relied on a smartphone app using GPS to guide the user. However, this proved insufficient due to the limited accuracy of phone-based GPS, especially in complex environments. To solve this, we shifted to an Arduino-based system using an MKR1000 board and a dedicated GPS module. We also developed a custom digital interface with a TFT screen that provides real-time guidance and distance tracking. The smartphone was replaced by a standalone, more reliable navigation module. We reinforced the structure with steel tubes and ASA 3D-printed joints. Two 20 cm front wheels ensure stability, while a tiltable rear wheel allows for curved paths. The spray system evolved from a simple 3D-printed lever to a precise mechanism using a bike brake and steel cables integrated into the handle. Each press marks the spot and resets the counter for consistent spacing. Demetro is now a modular, intuitive system designed to simplify complex mapping and planting, making reforestation more accurate, replicable, and accessible.
How it is different
What makes Demetro unique is its ability to combine analog precision with digital intelligence in a single, low-cost, replicable tool. Unlike traditional reforestation methods that rely on manual measurements, vague GPS apps, or expensive professional tools, Demetro offers a complete system, from digital mapping to physical marking and long-term monitoring. It’s designed to be built in a FabLab using accessible materials and open-source hardware, making it affordable and customizable. The integration of a detachable digital module with a high-precision GPS, TFT interface, and NFC reader ensures both accurate tree placement and traceability over time. Its modular design allows for multiple applications, from urban forestry to agriculture. Demetro doesn’t just guide where to plant, it connects people, technology, and nature in a collaborative and scalable process.
Future plans
Our next step is to improve Demetro’s accuracy by integrating RTK (Real-Time Kinematic) technology, which allows centimeter-level precision in positioning. This upgrade will enhance the reliability of tree placement, especially in dense or complex terrains. We also aim to refine the interface for greater usability and to test Demetro in real-world reforestation projects in collaboration with local communities. In the future, we hope to make the tool even more accessible, expanding its use to other environmental and agricultural applications.
Awards
Demetro was selected through a design competition and further developed in collaboration with Polifactory as part of the Distributed Design Market Platform. This opportunity, co-funded by the Creative Europe Programme of the European Union, allowed us to improve both the technical and design aspects of the project.
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