Final Design for Automatic Solar Tracker

I have decided on a final design that I will use to rotate a photovoltaic cell to track the sun. I will be using the design shown in Figure 1 below. The photovoltaic cell is placed on the black padding and held on with rubber bands. This wooden design includes a lazy susan that allows the photovoltaic cell to rotate in the phi direction. The base of the wood is marked with increments of five degrees. The vertical piece mounted on the lazy susan allows the photovoltaic cell to rotate in the theta direction.

Figure 1: Solar Tracker Design

 

 

To make this design automatic, I will add a servo motor to the base that will turn the lazy susan. The motor will be controlled by an Arduino that is receiving information from photoresistors which will be placed on the same platform as the photovoltaic cell. Depending on the amount of light that falls on the photoresistors (which will be separated by a wall), the resistance values will change and I will use this concept to write a code that will adjust phi so that both are receiving equal amounts of light. The theta direction will be initially set based on the calculations in the following link but will not change throughout the day. (Note: The Latitude of Loudonville, New York is about 43 degrees North)

http://www.solarpoweristhefuture.com/how-to-figure-correct-angle-for-solar-panels.shtml

 

I have downloaded the Arduino IDE (Integrated Development Environment) and have loaded simple programs on the Arduino Uno such as Blink or AnalogReadSerial to make sure that things are running smoothly.

 

This coming week, I will began to experiment with writing code that can read in data from a photoresistor and display it on the serial monitor.

Possible Designs for Automatic Solar Tracker

Last semester, I just rotated the solar panel 10 degrees manually every 40 minutes. This past week, I have been brainstorming possible designs that I can use to rotate my solar panel automatically. The following links are different designs that people have used to do similar projects.

2-Axis Solar Tracker

https://www.youtube.com/watch?v=5m5faWAhX4E

https://www.youtube.com/watch?v=sXsUiPKTdBs

Using a lazy Susan as part of the design but only rotating in phi direction

https://www.youtube.com/watch?v=ljTJqQYSJ8g

Rotating every so often – based on time rather than using photocell resistors

https://www.youtube.com/watch?v=44pfdK5UAp0

Arduino solar tracker but only in the phi direction

https://www.youtube.com/watch?v=1xoLTkjbuEQ

Solar tracker using Arduino that powers itself

https://www.youtube.com/watch?v=ATnnMFO60y8

I am in the process of collecting the parts that I will need for my circuit.
-Arduino
-Four photocell resistors
-Motor

In order to decide on what motors to use, I had to research the different types of motors.

Stepper vs Servo Motors:

https://www.lifewire.com/stepper-motor-vs-servo-motors-selecting-a-motor-818841

Stepper motors have a larger number of poles (typically 50-100) while servo motors only have about 4 – 12. This is important because the poles are the point at which the shaft naturally stops. This means that the stepper motor can be more precise in its movements. However, servo motors are better for high speeds and high torque. I have researched people who are working on similar projects and most of their designs seem to use servo motors. I believe these motors will be better for rotating the device holding my solar panels as it tracks the sun.

 

This coming week, I will decide on a final design and find/order the motors that are needed for my project. I will also start to build the design.

Project Summary

My project is to determine whether or not a moveable solar panel that tracks the sun can generate more energy than a stationary solar panel. First, I will set up both a stationary device and one that I can manually rotate every so often throughout the day, so that it will receive sunlight during all hours of daylight. Due to the fact that solar panels use the photoelectric effect to convert light to energy, I will be able to measure the voltage output from each panel and perform some calculations to find the power generated. Then I can compare the efficiency of the two solar panels and if the rotating solar panel proves to be more efficient, then I can create a design that will automatically rotate the device. The design will be an important part of the experiment because, in order for the mobile solar panel to be beneficial, it must use the minimal amount of energy to rotate.