I wanted to let folks know about the Photosynq (www.photosynq.org) beta test which is open for applications! Photosynq is a low cost, open source platform for taking handheld measurements of plant, soil, and seed health. Our goal is to create a network of low cost, hand-held measurement devices which researchers, educators, and citizen scientists can use to build a global database of plant health. Currently, we are focused on spectroscopic methods including photosynthetic efficiency and chlorophyll content, but we can also measure temperature, relative humidity, light intensity and color temperature (how much green, blue, and red), atmospheric CO2, and contactless leaf temperature. It's very hackable and is built around the Arduino platform.
Though the device is useful for an individual farmer, the website and online database enables anyone to quickly and easily share their data, and create collaborative research projects.
If you're interested in beta testing the device, please go here and sign up - http://photosynq.org/beta-test-application/. We expect to start the beta in late January.