I created an automated solar tracking system called SolarNAV for my STEM Capstone project which is designed to satisfy the needs for electricity generation in sub-Saharan Africa. Before developing this system, I completed a summer internship at the Colorado School of Mines robotics lab which taught me the essentials of mechanical and electrical engineering as well as some computer programming that I would need to complete this project. Although I had experience through this internship, I would find my engineering knowledge tested, especially with regards to finding the right parts for the system and developing the circuitry required to make the system function.
Before I even conceptualized the idea for SolarNAV, I started with a problem: the lack of electricity in sub-Saharan Africa. Energy is essential, yet developed nations have significantly more of this powerful resource than third world countries - effectively placing third world countries at a disadvantage compared to the rest of the world. I found that Sub-Saharan Africa is a major place where this energy deficit occurs with electricity being scarce due to a lack of electrical infrastructure, so I decided to cater my solution towards the needs of Africa. Once I identified the problem and confirmed user needs through research, I began brainstorming a solution, hoping to implement engineering practices in the real world to help other people.
I knew I needed to create an electricity generation solution, so I researched all the ways that electricity is currently generated. I found that burning coal is the primary source of electricity generation and renewables like solar and wind contribute smaller amounts. While coal is incredibly efficient, I decided that it wouldn’t be the best choice for Africa because it comes in limited amounts, is laborious to obtain, and it less environmentally friendly. Since Africans need a solution that is cheap, portable, and able to easily charge electronic devices, solar panels appeared to be a clear choice out of the renewables. Also, the sunny climate in sub-Saharan Africa near the equator would be ideal for solar panels. After contemplating how to implement solar panels in sub-Saharan Africa, I considered the fact that solar panels in a fixed position limit the amount of optimal sun exposure they receive each day, making them less effective. Thus, I decided to create a solar tracking system where the solar panel would alter its position with the sun for maximum sun absorption throughout the day.
Keeping in mind my design criteria of a portable, cheap, and user friendly system, I conversed with my mentor to visualize a design for the solar tracking system. Initially, I wanted to use a moving rover with a solar panel fixed on it that could drive around tracking the sun, but my mentor helped me realize that a rover would be unnecessary, overly complicated, and not cost efficient. Then he suggested modeling my solar tracking system from a ball and plate system where a plate alters its position to prevent a rolling ball from ever falling off the plate. Instead of controlling the position of the plate relative to the ball, I would be controlling the position of the solar panel relative to the sun. Realizing that his idea fit my design criteria much more closely, I decided to go with it. Now for the hard part: actually creating the design. I hardly had any background in mechanical engineering, so I decided to communicate with my mentor on how to go about building a solar tracking system. Since engineering is all about building off of previous knowledge and design, he suggested that I use the same structure that a classmate had used at Colorado School of Mines to build an actual ball and plate system. After using his same design, I had an acrylic box that he laser cut for me and various screws and linkages that I would need to connect the servo motors with the plate. With the mechanical design of the ball and plate system finished, I began altering it to meet the needs of a solar tracking system. First, I had to fasten the solar panel onto the plate which I accomplished using double sided tape at my mentor’s suggestion. Next, I had to lengthen the arms of the servo motors because the plate wouldn’t tilt far enough for the solar panel to be effective otherwise. I ran into plenty of problems during this design stage, especially with the central universal joint connecting the solar panel to the acrylic box being too loose, but with the help of my mentor I was able to complete the mechanical portion of the project.
With the mechanical portion complete, I moved onto the electrical portion of the project - the most difficult part since I had little knowledge in electrical engineering besides basic breadboarding. First, I knew that I needed an Arduino microcontroller to control the servo motors. Second, I knew that I would need to control the position of the plate through the servo motors based off of sensor data from photoresistors. With these goals in place, I decided to get to work. I started by learning how to program the servo motors to move with the Arduino. Then I moved onto trying to get the plate to set in various positions based off of programming with the servo motors. Now for the difficult part - I had to figure out how to power the Arduino and servo motors with a 12 volt lead acid battery that would be simultaneously charged by the solar panel. Therefore, the battery would be charged by the solar panel and power the system at the same time. With a higher voltage and a risk of dangerous short circuiting, I spend a lot of time researching and talking with my mentor before I finally started putting the circuit together. There were certainly some problems - I burned up a resistor and saw a few sparks fly - but I made it work in the end. My end circuit design relied on power distribution blocks that fed all of the wires into single terminals to fix the confusing mess of wires before me. Some unfamiliar components I had to implement in the circuit were in-line fuses, buck converters to drop the voltage from the battery to the Arduino, and a switch to turn the whole system on and off whenever necessary. Easier said than done, I finally completed the circuitry and was ready to start testing my system outside.
My experiment consisted of comparing fixed position solar panels to my solar tracking system which I now deemed SolarNAV. The programming took forever to correctly adjust the position of the solar panel to the position of the sun outside, but I eventually accomplished it with satisfying results. After a month of comparing my system to fixed position solar panels, I had a load of data to use to determine the effectiveness of SolarNAV. I determined that SolarNAV is more effective than fixed position panels on an energy basis. Now I took my findings to the Denver Metro Regional Science and Engineering Fair to see how effective my solution appeared in the eyes of people working in the STEM field. With suggestions from my teacher and classmates on how to present, I pitched my project, hoping to succeed in the fair. I received a lot of helpful tips during the fair and points of emphasis I could focus on with my project, notably the cost of developing the system, which helped my to improve my design going forward. Next, I presented to a panel of STEM judges at the Capstone Boards Presentations at Green Mountain High School. Through presenting to the judges, I learned how design collaboration functions in the workplace to provide multiple perspectives on a design solution in order to make the design as efficient as possible.
My greatest reward from this capstone project has certainly been the knowledge I have gleaned through experiencing the engineering design process firsthand and implementing different branches of engineering like mechanical and electrical as well as computer science. Through designing a solution to a real world problem, I learned valuable skills ranging from creativity to considering user needs and empathy. I also interacted deeply with the STEM community throughout this project through the science fair and capstone boards presentations which helped me see what STEM is all about and expanded my perceptions of the possibilities in the STEM field. People in the STEM field are making incredible contributions to society which I truly began to understand through meeting people in the field and learning about their amazing projects. Working with my mentor especially taught me how engineers think about the world from a problem solving standpoint and how collaboration is essential to any successful design solution. In its essence, SolarNAV is something I can be proud of creating and it will always serve as a reminder to how my career in engineering began - starting with a problem, an idea, and a support system to cultivate that idea.