Preliminary Design Document

Stacked Hydroponics Growing System for Vertical Farming

Preliminary Design Document

by Richard Reynolds

Prelude:

As the world's population increases, the job of feeding this population becomes increasingly difficult. From the issues of simply finding the space to produce the food to the effects of over farming the available space to the effects of the chemicals used to increase crop yields; the problem is becoming more and more pervasive. And now, with the use of GMOs and the unknown long term consequences they could present we are obviously reaching a tipping point. We do not yet know whether GMO based food crops could cause real problems, but the food supply situation has reached a point where we don't seem to have time to properly research them. So we forge ahead and hope for the best.

One possible solution to the problem might be found in the concepts of vertical farming. Vertical farming methods could be incorporated by the growing industry into existing grow spaces to greatly increase yields while reducing environmental impact. While at the same time better managing the runoff of chemicals into the environment. Ultimately producing as much food as possible in as small a footprint, both physical and chemical, as possible. There are currently many methods being researched that might accomplish these goals. They range from systems that provide planting space around the sides of a vertical column to automated plant inverted "Ferris wheel" systems that move large numbers of plants in a manner that allows them to receive and share light and nutrients in a relatively small footprint. And more simply, vertical gardening can just be a way for a family to produce fresh wholesome food in their homes suing very little space. And possibly, this is the real answer to the problem. Because the more people who do this the smaller the big problem becomes.

Background:

I am not an electrical engineer. I do however have an electronics background via an associates degree in applied electronics technology that I received in the early 1980s. I worked as a technician for the first several years after school. First I opened and managed a computer repair center for Tandy Corp. and then went on to work as an R&D technician for a maritime radio station. In that time, During this period I taught myself to administer UNIX/XENIX based computer systems and to develop application and systems software using the C programming language. Eventually, I became a full-time programmer and systems administrator. Now 30 years later I find myself back in the combined hardware and software world. I am currently an embedded software developer for an engineering services and software company. This is definitely my preferred calling.

Reason for applying:

I am very interested in this particular challenge. This is because it brings together elements of the more complex and esoteric technologies of computer software and electronics design and marries them with the more practical and mundane technologies of simply providing the food we eat. And because the project goal is not to create just another gadget. Some of the aspects of this challenge that interest me most are:

• The opportunity to explore some of the latest microcontroller, sensor, and wireless communications technologies. I have professional experience working with Digi's Rabbit microcontroller modules, using Dynamic C on bare metal and with the Arduino 2560 Mega and Wiring as a hobbyist. I also have professional experience working with several embedded Linux platforms. Namely, Beaglebone Black and Raspberry Pi, using C/C++ cross compiled from Eclipse and C# via Mono and Monodevelop. I would like the opportunity to do more work with microcontrollers at a bare metal level.
• The concept of the marriage of computers, electronics and farming/gardening technologies. I have built several small hydroponic gardens, but none incorporating electronic control and monitoring.
• The concept of solving very basic human problems using cutting edge technology. As opposed to building just another gadget to clutter up our lives.

Project proposal overview:

Definitions:

Growing area - An indoor area designated for the cultivation of edible plants.

Grow station  - An area that provides space enough to grow one to two individual plants.

Planting unit  - A single stackable container. Each container should provide three to four grow stations.

Stacked grow unit - Some number, four to five, of plating units stacked in a single tower arrangement.

My proposal consists of the design and implementation of aeroponics/hydroponics based stacked grow units using vertically stacked planting units. And of a wireless control and monitoring system. The concept of smaller stackable units will allow for small, one stacked grow unit, home-based installations as well as the ability to scale up into fully commercial installations. My proposal for this challenge is to build a 20 grow station system, a grow area centric wireless slave control/monitoring system, and a centralized wireless master control/monitoring system. Time and budget permitting I will also include a cloud-based data logging and presentation element.

The entire system will consist of the following elements: Understanding that all design elements are subject to change as the project progresses.

Growing:

• One large container that will act as both a stabilizing base and as a water/nutrient reservoir. This will consist of a plastic or fiberglass tub or grow pot of sufficient size to accommodate water and nutrient solution for up to 20 individual plants. The base will be built so as to provide 360^o oscillatory rotation. The rotation of the base will be automated and is used to provide uniform controlled lighting to all plants. Automation will be via the control/monitoring system described below.
• A 20 grow station aeroponic/hydroponic garden, or stacked growing unit. This will consist of 5 stackable planting units, providing 4 grow stations each.
• Water and nutrients will be provided by pumping a hydroponic solution up through the middle of the stacked grow unit. A dispersal head will be installed at the top of the unit so as to provide a mist or flow to the top planting unit. The remainder of the planting units will be supplied with hydroponic solution via gravity feed as a result of the top, and each subsequent unit's drainage.

Lighting:

• Some number of modular, possibly stackable, LED or Halogen Lamp grow light units. These units will be oriented in columnar fashion so as to match the height of the vertical grow unit. Lighting exposure times will also be automated via the localized control module described below. Allowing optimum lighting for all phases of plant growth and yield.

Automation:

Grow area centric control and monitoring system:

• A growing area wireless control/monitoring system. This system will act as the data acquisition and control platform for the individual stacked grow units. It will monitor various environmental conditions and control all lighting and plant watering/feeding operations and will also provide low-level energy usage monitoring through the onboard AEM. This system should be capable of controlling and monitoring some number of stacked grow units. It will consist of the following elements:
• A Silicon Labs EZR32WG 915MHz wireless ARM based microcontroller unit. This unit will interface to all stacked grow unit sensors and control devices. It also contains some additional onboard sensors, including low-level energy usage sensing, that may be incorporated into the control/monitoring process. This unit will also act as a communications link back to a centralized control/monitoring system.
• A Silicon Labs Sensor-Puck board. This board contains environmental sensors that will be used to monitor conditions in the immediate area of one, or a small group of, stacked grow unit(s).
• Custom software application(s) for controlling and monitoring the local unit(s). And to provide a software to the remote wireless microcontroller unit.

Centralized control and monitoring system:

• A centralized wireless control/monitoring system. This system will act as a centralized master control/monitoring system for a single stacked grow unit or a group or multiple groups of stacked grow units. In the case of multiple or groups of multiple grow units it will serve to aggregate monitoring data and provide a centralized single point of control for all grow units. It will consist of the following elements:
• A Silicon Labs EZR32WG 915MHz wireless ARM based microcontroller unit. This device will serve as the central processing unit for the vertical “farm”. It will receive and log monitoring data for all available remote units. It will also serve as the master controller for all remote units.
• Custom software application(s) capable of controlling and monitoring a single stacked grow unit or multiple or multiple groups of stacked grow units. And to provide a user interface for all control and monitoring functions.