When Mary Bao, Mike Hua, Jack Kaplan, Harrison Lin, Colin Losey, and Lingbo Chen were tasked with developing an indoor greenhouse, they opted for old school soil farming instead of hydroponics. The Rice University engineering students (Chen is an electrical engineer while the others are mechanical) worked with the HSB Living Lab at Chalmers University of Technology in Gothenburg Sweden on the project for their capstone design course.
The students decided on a traditional soil system to allow for deeper root penetration and the ability to grow a wider variety of plants and vegetables. Vaxthus is the name of the project, the Swedish word for greenhouse, and the soil and vegetables sit inside a wood and acrylic frame. The system is fully automated on a closed loop system but manual controls were added for users to customize growth based on personal preference. Water and light are the controlled parameters, and the touchscreen display shows the user moisture, temperature and humidity data. A pump acts as raindrops dripping water onto the plants and then recycles that water from the lower drip tray. Kale, herbs, carrots and radishes were all tested in the first prototype unit, and two additional units were constructed for installation at the Living Lab.
Vaxthus is a great project from a capstone design sense. The students took the design constraints for their greenhouse - automation, modularity, urban setting, and built a system that met those constraints. Mixing mechanical and electrical engineers is a great way to foster teamwork, it's easy to see both the mechanical design aspects of the project and the control and programming areas. The design won the Shared Space Challenge in June and team member Mike Hua posted a mesmerizing video this week of the system during a watering cycle.
(Photos courtesy Rice University)