Winter is coming...

Name: Victor Hsu
Affiliation: Oregon State University
Phone: 541-737-4398
E-mail: hsuv@onid.orst.edu
Website:
Knowledge Required: A programming language compatible with a microcontroller (assembly, C, Arduino toolchain, etc.), an interest in plants, and a desire to toy with Mother Nature.
Motivation: We like to cook, and fresh herbs really make a delicious difference in the taste of the food. Unfortunately, the growing season in Oregon is pretty short, so we are relegated to trying to grow the herbs indoors. However, the color of traditional grow lights is pinkish-purple in color, which is a rather harsh color to have inside a home (these are colors that our daughter really likes, but are colors we don't want to have to look at all day long). By using a microcontroller (like an Arduino), some RGB LED strips, and a pre-existing LED library (like FastLED), it should be straightforward to put together a indoor grow light system that can cycle through the useful colors, as well as provide white and full-spectrum light (research shows that both are also important for plant growth) in an energy and cost efficient manner.
Description: You live in Oregon, so answer this question - what does the Oregon winter bring? Death to outdoor plants, that's what. So while delicious and useful herbs flourish in the spring and summer months, they don't do so well in the winter. However, bringing them indoors, or growing them indoors can be challenging, mostly because of the light. Plants contain chlorophyll, which are molecules involved in photosynthesis and are essential for plants to absorb energy from light. The absorption spectrum of chlorophyll (https://en.wikipedia.org/wiki/Chlorophyll) shows maxima for violet-blue and orange-red light, which is why many grow lights are pinkish in color. Studies have shown that: blue light increases a plant's growth and maturity rates; red light yields more leaf growth and larger crops; violet light enhances plant color, taste and aroma; and green light enhances chlorophyll production. So, how could you control light color and intensity for optimal plant growth and health at home? Strips of RGB LEDs! In fact, according to NASA scientists, LEDs provide the best source of lighting for indoor plants (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150009399.pdf). The goal of this project is to develop a microcontroller-based LED lighting system for the indoor cultivation of plants. Using a spectrophotometer, RGB values will be determined that maximizes energy absorption by plants, and these values will be used in the lighting system.
Objectives: RGB LED strips can be programmed to yield any color of light at selectable intensities. By using a spectrophotometer that I have in my lab we should be able to characterize the spectral and intensity properties of the LEDs by setting different RGB and intensity levels. These values can be programmed into a grow light system optimized for plant growth and health. The objective of this project is to develop an indoor grow light system that can be programmed to turn on and off at selected times, cycle through the different optimal colors, provide white light, provide full-spectrum light, a combination of the above, or even provide different light at different plant positions, all based on user need.
Deliverables: At the end of the process, there will be a designed, programmed and working indoor grow light system prototype. Depending on the desires of the team, the code and hardware can be released as open source, or can be marketed and sold as kits.
Other comments: For this project, no knowledge of electronics (or biochemistry) is required, the need is for programming. There is no circuit design needed as we will simply be hooking up LED strips to a development board. I will provide the microcontroller boards, LED strips, and plants (unless you have your own plants you want to use as test subjects!).

   D. Kevin McGrath
   Last modified: Thu Nov 16 11:32:03 2017