A smartphone-powered device reads gas concentrations to detect plant diseases.
Developed by a team from North Carolina State University, the device is based on the knowledge that certain volatile organic compounds given off by plants can indicate disease. A sample leaf from the plant in question is placed in a sealed test tube for about fifteen minutes—where it releases VOCs. Those gases are then pumped to a chamber containing a strip of test paper embedded with reagents that will change color in the presence of certain VOCs. The color change is imaged by the smartphone’s camera and then interpreted by the user, although the team is developing an app that will read the results automatically.