Smart Chambers and Sensor Networks: Monitoring GHG Fluxes with DIY Innovation

To measure greenhouse gas (GHG) exchange in real-time and at high resolution, Work Package 3 (WP3) is developing low-cost, multi-sensor chambers designed for long-term, autonomous deployment in the field. These portable devices—built using open-hardware principles—will integrate sensors for CO₂, CH₄, N₂O, NOx, VOCs, and environmental variables, operating as modular “electronic noses.” With robust microcontroller programming and remote data connectivity, the system aims to reach TRL 5–7, enabling reliable field validation and paving the way for scalable ecological monitoring technologies.

We intend to quantify the net GHG exchange in our study sites. This entails measuring C fluxes throughout the seasonal cycle. To achieve this, we plan to obtain high-resolution measurements (both spatially and temporally) by developing low-cost multi-sensor equipment^1,2 that allow for extensive deployment in Work Package 3 (WP3). WP3 will focus on the design of a light and portable measurement chamber for in-situ gas measurements. The chamber will integrate the selected sensors for target gases and for environmental variables, the electronic circuit, the microcontrollers and the power supply. The chambers are designed to operate autonomously for an extended period of time (months), requiring only occasional basic maintenance and field re-calibration. In some cases, we will test novel developments of sensor technology (e.g., BVOC and metal oxide sensors^3,4). We will implement sensing nodes that will integrate multiple sensors in a setup that is known as an “electronic nose”, a cutting-edge technology that comes from the biomedicine sensing field.

**Basic design of an automated chamber.** Chambers with different sizes and configurations will be adapted to measure flows in water surfaces^3,4, shrubs, tree leaves⁵, and stem⁶.

According to Commission Decision C(2014)4995 on Technological Readiness Levels (TRL)⁷, we aim to achieve at least TRL5 (technology validated in a relevant environment) and ideally TRL7 (system prototype demonstration in an operational environment). This would position our multi-sensor design for the innovation phase and potential industrial application. This work package includes five tasks:

Task 3.1 Sensor selection and delivery system:

The sensor selection will be carried out carefully according to expected environmental field conditions and expected concentration ranges for each target volatile. The targeted chemicals will be CO₂, CH₄, N₂O, Volatile Organic Compounds and NO_x.

Task 3.2 Node design and implementation:

This task focuses on the development of the initial batch of prototypes for low-cost, DIY monitoring sensors. The prototypes will undergo configuration tests using various microcontrollers such as Arduino, STM32, and Raspberry. Specific routines and libraries will be written, tested, and optimized to program the microcontrollers. This includes activating the sensors, valves, and fans, checking their functionality, ensuring power autonomy, setting the data acquisition frequency and storage, and establishing real-time communication.

Task 3.3 Node connectivity:

Real-time communication between the sensor nodes and the cloud will ensure seamless data transmission and integration and remote data access. The communication protocol will be selected depending on the application requirements and environmental conditions. Also, the node will include a local storage device (SD card) to save the data locally and ensure completeness of the acquired dataset.

Task 3.4 Open hardware:

This task aims to establish an open-hardware and open-software ecosystem that promotes accessibility, transparency, and collaboration within the community. The design process will be thoroughly documented, encompassing schematics, PCB layouts, and bill of materials, to facilitate replication. Likewise, the software, including microcontroller routines and sensor configurations, will be released under open-source licenses, ensuring that the source code is freely available for modification and redistribution.

Task 3.5 Field tests:

Before deployment, the developed sensing nodes will undergo testing to ensure their functionality and reliability. Initially, the sensors will be tested under controlled conditions to verify their proper operation and measure background and noise levels. Once the sensors’ responses to different stimuli are validated, a few prototypes will be distributed to site operators for testing in real-world field conditions. This task also involves making technical modifications and adjustments based on the field testing.

¹Pearce, J. Materials science. Building research equipment with free, open-source hardware. Science 337, 1303-1304 (2012).

²Porter, J. H. et al. New eyes on the world: advanced sensors for ecology. BioScience 59, 385-397, doi:10.1525/bio.2009.59.5.6 (2009).

³Butturini, A. & Fonollosa, J. Use of metal oxide semiconductor sensors to measure methane in aquatic ecosystems in the presence of cross-interfering compounds. Limnology and Oceanography: Methods 20, 710-720 (2022).

⁴Bastviken, D., Sundgren, I., Natchimuthu, S., Reyier, H. & Galfalk, M. Technical Note: Cost-efficient approaches to measure carbon dioxide (CO<sub>2</sub>) fluxes and concentrations in terrestrial and aquatic environments using mini loggers. Biogeosciences 12, 3849-3859, doi:10.5194/bg-12-3849-2015 (2015).

⁵Miyama, T., Kominami, Y., Tamai, K., Nobuhiro, T. & Goto, Y. Automated foliage chamber method for long-term measurement of CO2 flux in the uppermost canopy. Tellus B: Chemical and Physical Meteorology 55, 322-330, doi:10.3402/tellusb.v55i2.16692 (2003).

⁶Helm, J. et al. Low-cost chamber design for simultaneous CO2 and O2 flux measurements between tree stems and the atmosphere. Tree Physiology 41, 1767-1780, doi:10.1093/treephys/tpab022 (2021).

⁷EURAXXES. About Technology Readiness Levels https://euraxess.ec.europa.eu/career-development/researchers /manual-scientific-entrepreneurship/major-steps/trl, 2024).

The Bio-Physical Environment: High-Resolution Monitoring of Carbon and GHG Fluxes

Headwater catchments are composed of distinct landscape units—grasslands, shrublands, forests, soils, and water bodies—each playing a unique role in carbon and greenhouse gas (GHG) dynamics. This article outlines how variations in vegetation, altitude, and land use shape these systems and how climate and nutrient deposition act as key drivers of change. In Work Package 4, we deploy novel sensors to monitor carbon and GHG fluxes across a full seasonal cycle. These high-frequency measurements help us track both steady processes and abrupt climate events, improving our understanding of ecosystem responses in a changing world.

Tracking Carbon and Nutrient Dynamics Across Europe’s Headwaters: A Biophysical Approach to Climate and Ecosystem Change

SERVICO2 will re-analyse long-term data from 13 headwater catchments across Europe to assess trends in carbon export, weathering, GHG emissions, and water quality. This work supports climate modeling and ecosystem service evaluation at the continental scale.

Socio-ecological Valuation of Ecosystem Services in Headwater Catchments: Co-creating Governance for Atmospheric CO₂

SERVICO2 aims to advance the socio-ecological valuation of ecosystem services, focusing on CO₂ regulation in headwater catchments. Through stakeholder mapping, ES assessment, and co-creation workshops across Europe, the project promotes inclusive governance and informed climate policy.