Grow Controller: Supervisory Control and Data Acquisition (SCADA) for indoor agriculture

Clarkson University has several interesting research topics going on, including several projects relating to indoor aeroponic agriculture. The science includes lighting system analysis, nutrient mixes, plant growing environments, and other topics. The initial aeroponics control system, developed by researchers at Clarkson, used off-the-shelf programmable logic controllers. This equipment was very expensive to install, and this led to the idea of developing a stand-along indoor integrated grow controller. Using lessons learned from my experience with the Magic Claw, I designed a modular, low-cost grow controller to replace the PLCs that were used in the prototype greenhouse.

The photo shows the first revision of the controller. This unit is the first "line powered" device I have built, using a listed 120VAC to DC level converter, which is the large black box on the upper right of the board. This board has, at upper left, a connector for remote sense boards, described below. Then there is an AUX connector for various analog inputs common to the agriculture industry.

This shows the Expansion board. This is meant to control a single "Grow zone" under supervisory control of the base controller, descirbed above. This board plugs into the remote sense conector, and can be daisy chained together. This provides 4 more relay outputs for zone-based fan, light, or pump control, plus a header for 0-10VDC output for dimmer control. In addition, it has connectors for up two two "leaf zone sense boards", which measure irradiance and environmental conditions in the leaf zone. There is a little white knob in the left center of the board: That sets the address of the board, which is then auto-detected by the grow controller.

This is version two of the grow controller. The connector at the upper left can still connect to expansion boards and leaf-zone boards, but this unit has more features: More relay outputs, higher accuracy analog inputs, a Real Time Clock (RTC) and more nonvolatile storage. This enables the board to run recipes and survive blackouts, the latter of which is extremely important for aeroponics operation. The V03 board, currently under development, adds even more features, including support for standard SCADA communications protocols and a slick and awesome web-based data historian and interface.

The final photo shows the V02 grow controller hooked up to some of its sensors, for testing the accuracy of the analong inputs channels. This is the local control for the grow controller, and is the same LCD Interface as is used with the Stage 1 crane controller board.