Seniors design gas exchange chamber for Biosphere 2 plants

A team of University of Arizona seniors is working with Biosphere 2 to better understand the global carbon cycle. Interdisciplinary Capstone Team 26040 3D-printed an autonomous leaf chamber that measures how plants exchange gases with the atmosphere – a key indicator of photosynthesis and plant health.

“We’re designing a device that can automatically measure gas exchange while being affordable and easy for researchers to use,” said Molly Auer, mechanical engineer and team lead.

The team’s small, transparent chamber attaches to a leaf and automatically records environmental conditions including light, air temperature, leaf temperature and humidity. When the chamber closes, it draws air through a gas exchanger that measures carbon dioxide and water vapor concentrations, letting researchers monitor plant activity more efficiently. 

Balancing precision with accessibility has proven to be the team’s steepest challenge. Commercial gas-exchange systems used in plant research can cost tens of thousands of dollars. The students are designing a system that delivers reliable measurements at a significantly lower cost and deploys across multiple plants at once.

To get there, the team shifted from traditional fused deposition modeling to resin 3D printing. Resin printing offers higher precision – crucial at the scale the team is working with – and helps ensure the sealing mechanism achieves an airtight fit.

If successful, the automated chamber helps researchers collect continuous data throughout the day without manually monitoring each measurement. 

"Everyone on my team brings a strong background to the table," Auer said. "Working with members from different engineering disciplines has really helped spark new ideas, curiosity and motivation to move this project forward together."

Watch Team 26040 showcase their work at the Craig M. Berge Design Day on May 4.