S08 - Session P1 - Design of vertical farm and space farm - Design of low cost, open-source growth cabinets for evaluating growing media and crop suitability for space environments

Authors: Harry Wright *, Alexis Moschopoulos, Luke Fountain

Controlled environment growth cabinets for evaluating growing media and crop suitability are costly and complex systems making research into these fields prohibitive for citizens or small research groups. With a renewed interest in space exploration and research into crop growth in space we have designed open-source benchtop growth cabinets with the same internal dimensions as that of the Advanced Plant Habitat on the International Space Station. The growth dimensions are 40 x 40 x 40 cm with a media tray insert of dimension 5 x 40 x 40 cm. The cabinets have two channels of LED lighting, five white light units as well as four full spectrum LED units which use passive cooling and can be independently tuned using potentiometers. Temperature and humidity are not controlled by the cabinets and they are expected to be placed in an environment where those factors are in an acceptable range to not hamper the selected crops growth. A Raspberry Pi is used for logging of environmental factors as well as controlling irrigation events. A GrovePi+ header is used on the RPi for ease of adding and removing sensors. The growth chambers have a temperature and humidity combined sensor (AM2302), a light sensor (TSL2561 ) which monitors light intensity only (Lux) as well as a pair of analogue capacitive moisture sensors which control irrigation events using a threshold media moisture level. A 5 V pump is controlled through a relay connected to the RPi and this irrigates the media using a dripper based irrigation ladder. A digital camera is also connected to the RPi to capture photos of plant growth from above. Each growth cabinets costs ~GBP900 (USD1200) and we have built a pair such that one factor can be changed and growth between the two cabinets can be compared.