Carbon Dioxide Sensor

Carbon Dioxide Sensor (Archived)

Environmental Stewardship & Social Justice


With increasing concern for climate change and the environment, analysis of water and CO2 exchange in plants is needed to assist sustainable land planning. Plants play a key role in regulating the carbon dioxide content of the Earth’s atmosphere, and with the destruction of natural habitats for resources and urban development, finding sustainable options to replant can help urban, drought and fire affected areas reduce their carbon footprint and water consumption.

Plants use two primary functions to produce and store energy: photosynthesis and respiration. Photosynthesis describes the chemical reaction in plants that converts CO2, water, and sunlight into glucose and oxygen,

6CO2 + 6H2O = C6H12O6 +6 O2,

and respiration describes the conversion of glucose and oxygen into CO2, water, and energy in the absence of light,

C6H12O6 + 6O2 = 6CO2 + 6H2O.

Transpiration describes the exchange of water between the plant and the air around it during photosynthesis and respiration. Water is carried from the roots to the leaves during photosynthesis, and then released through the leaves during respiration.

Unfortunately, existing CO2 measurement systems for analyzing the photosynthetic CO2 exchange, respiration and transpiration of plants often cost over $10,000 dollars and require manual data collection, proving costly and inefficient.

Goals and Design

We hope to create a system for under $200 that can be used to capture a leaf's respiratory rates in situ. Our goal for making this measurement chamber accessible to all is to facilitate the creation of a plant library that identifies the effects of climate and environment change on transpiration. Ideally, we could also use this data to identify optimal plants for carbon sequestration for a given area. Current systems cost thousands of dollars and are human operated; they cannot be left out in the field for repeated measurements. Our system will be viable in the field and automated using Arduino or RasPi without compromising the quality of data, making this data more accessible and promoting sustainable land planning. We will develop this system using readily available components and make the design open source, so that anyone can build and improve upon our design.

We will perform a comparison of a Raspberry Pi compatible apparatus, using an affordable CO2 sensor with relative humidity and temperature measurement capabilities, to an $8000 analysis system. Our preliminary apparatus will be under $200, consisting of leaf holder made of PET, EPDM weather resistant foam gasket, a clamp and the COZIR sensor, operated by a Raspberry Pi. The preliminary design of our leaf holder is shown in the image below.


In later stages of experimentation, an actuator will be installed to open the leaf holder periodically and refresh the air supply, with the CO2 sensor will taking data every few minutes.

If we can successfully balance the cost and quality of data for our automated CO2 analysis system, we hope that scientists and environmental enthusiasts alike can access this data to promote a sustainable future. Ultimately we hope that this alongside the plant library will promote informed decision making about the plants we choose for CO2 uptake and water conservation.