Executive Summary

Our team knew that creating an automated hydroponics system was not going to be an easy task, but we did not know the extent of it until we began. Together, we had nine months to create a hydroponics system that was customizable, user-friendly, and automated the watering cycle and nutrient-dosing routines. These nine months were abruptly shortened to six months due to the COVID-19 pandemic; nevertheless, we created a system we were proud of. This executive summary highlights those six months of project development and the wrap up, presentation, and reflection periods that followed.

Problem Statement

Hydroponics is a method of gardening that grows plants in nutrient-infused water instead of soil. This technique allows plants to grow faster, use less water, and produce higher yields than traditionally grown plants. However, hydroponic systems typically require considerable supervision and maintenance.

Project Goals

Our team is continuing the work of Paul Suess and Jose Torres: two OSU students who began creating a hydroponic system for ECE Senior Design in 2018/19. Using their existing work as a baseline, we set out to create a hydroponic system that was

• Automated
• Customizable
• Easy to use

Through these goals we envisioned a system that anybody could use to grow plants with minimal supervision, minimal maintenance, and minimal water. We named this system Hydrogrow.

Design Process

Creating an automated hydroponics system is a complex task with many steps and requirements. To make the process more manageable, we divided the project into three phases:

1. Prototype

During this phase, our team consulted with our client weekly to learn more about hydroponics and his visions for Hydrogrow. He also lent us his prior experience with the project to guide us toward an improved design. Together, we developed a full system block diagram, and started to create prototype versions of the web interface, node PCBs, and node enclosure. By the end of this phase, a proof-of-concept and initial documentation for these block was completed. This phase took place during fall term.

2. Create

During this phase, we took our block prototypes and continued to refine them. We also developed the base station PCB, and base station enclosure, which became a much longer, more arduous process than expected due to the large number of peripherals it supports. During this time, we continuously consulted with our client to ensure the design followed his specifications and we consulted with a professional electrical engineer to verify that our design would work as intended. This phase took place the first seven weeks of winter term.

3. Integrate and Evaluate

During this phase, we tested each block individually and combined them to create a complete system prototype. The integration portion required us to work together closely, using digital communication methods, such as Slack and Google Drive, and in-person work meetings. We spent about a week in the lab hooking up all the hardware, slowly testing it, debugging it, and adding more functionality to the software. By the end of this phase, we planned to have all of the system’s engineering requirements completed, however due to COVID-19 restrictions, we were only able to complete seven of our 12 requirements. This phase took place during the last half of winter term.

Current Status

Our system prototype at the end of winter term had all of the hardware and the majority of the software completed. For our final system checkoff, we completed the following engineering requirements:

1. Fault Notification
2. Remote Access
3. Instant Autonomy
4. Ease
5. Unique Watering
6. Local Display
7. Water Frequency

In completing these engineering requirements, the system can currently boot up and connect to WiFi from power on; the user can set the watering frequencies for two nodes using the web interface; the system can pump water to and from the trays according to the user-provided watering frequencies; it can detect the reservoir water level and display it on the local display and web interface; it can also detect various disconnection/leaking faults and alert the user via email. The features we never finished implementing include nutrient and pH regulation and reservoir water circulation. Additionally, the software needs to be updated to support two nodes.

Since project development has stopped, our team has cleaned up existing project artifacts and documented our work such that it will be easy for another group to take over. We have continued to work together via Slack and Zoom to prepare Hydrogrow for the virtual expo and showcase.

Looking Back

Overall, project development went more smoothly than expected. This is mostly because our team was in constant communication with each other, had guidance and tips from our client about what worked and what did not work with the previous iteration of the project, and tried to thoroughly document the block interfaces before working on the implementation. The most difficult aspect of the project was trying to manage our time while juggling so many PCB peripherals, but because we were meticulous while during the design phase, the integration phase did not take long; there were only a few PCB connection changes and software edits we had to make. If we had more time to work on this project, we are confident that we would have a fully functioning hydroponics system. Some of our other challenges and the next steps to complete the project are documented below.

Challenges

One technical challenge that we encountered while working on Hydrogrow was how to monitor the volume of nutrient solutions without using an in-solution sensor. The concentrated nutrient solution causes in-solution sensors to corrode, eliminating this as a viable option. Our team was able to conquer this challenge by using an ultrasonic sensor to measure the solution level without coming in contact with the solution itself.

A logistical challenge we faced was ordering PCBs from China during the coronavirus outbreak. PCB manufacturing companies in China offer low-cost PCBs, which was attractive as we tried to minimize costs whenever possible. Due to the outbreak, production was slowed and even halted at times, which affected our timeline. To account for this delay, our team needed to finish PCB design earlier than expected in order to finish the project in time.

Next Steps

With more time to work on the project, our team would like to successfully implement pH and electroconductivity sensing. Circuitry for these sensors was designed and included on the PCB, but was never fully tested and proven to work correctly. This is a major part of the project and would be a clear next step.

Another addition to the project would be to include temperature sensing as pH and electroconductivity measurements are directly affected by temperature. This would allow for the system to more reliably sense pH and electroconductivity through fluctuating temperatures.

A final addition would be to include a drain to prevent water overflow in the case of an electrical failure. The current system relies entirely on the pumps and control signals to fill and drain the growing trays. In the case of a fault, in which the watering cycle is started but the control signal to stop the pumps is never sent, the system would overflow the trays. The addition of a drain into the growing trays would help to eliminate the chances of flooding.

A complete listing of next steps for this project is included in the Next Steps document.

Final Project Timeline