81. Simple solar tracker

In this day and age, solar panels were invented to produce a renewable source of electricity and ensure that the environment we live in stays clean. In simple terms, the way a solar panel works is that photons travel into the panels, knocking off electrons in the body. With the space from the knocked-off electrons, the rest of the elections run in to fill in the empty space, generating electricity.

<Finished unit>

While it does work, most solar panels are stationary, which means they can only produce energy up to a point, but as the sun moves, the energy produced is smaller. Since it cannot change its position, it will not find a way to produce as much power as it can every time the sun changes direction.

This is why something like a solar tracker is needed to ensure that the solar panel will always get the maximum energy collection needed to create a high output. To do this, you will need a solar panel, usually a small one as a prototype for your project.  You will also need 2 LDR(light-dependent resistors), a small servo, an Arduino, and 2 10k ohm resistors and wires. For added complexity/visualization, you can use an LCD with a DHT11 sensor for checking the environmental status You will also need hardware components, such as a plate to house the electronics, a foamboard to act as a reflector, and bolts/nuts to make the main plate like a table.

<Pre-setup>

To start, try to drill 4 holes into the plate so you can insert the long bolts into them. Thus as mentioned, you turn the plate into a table for the electronics. For my method, I want to start with the LCD and the DHT wiring first, so that is what I'll do. Wire up the negative lines and the positive lines (Such as the led backlight) to the Arduino power lines, and the data lines (Reset, Enable, d4, d5, d6, d7)  to the Arduino's digital pins. Make sure that the LCD works with the Arduino by making a test print, which can be done by importing the LCD library, initializing the LCD, and using the "LCD.print" command. Once you have it done, solder the DHT leads, going with the same powerlines, and hook up the signal lead to the empty digital pin. use the example library that uses the int data from the sensor, and prints it to the LCD.

Once you got it, build a reflector plate with the foam board, which you insert the LDR sensor on both sides, and solder the leads to the power line and the resistor to create a voltage divider. The signal pin will go to the analog pin of the Arduino, the positive line of the LDR, and the ground line of the resistor.

<Under the reflector>

Wire up the small servo, going by the power lines and the signal line respectively, and attach a wheel with a beam, to the servo. Find a way to glue the end part of the beam to the reflector, and then double-check to make sure the 3 sensors, the servo, and the LCD, are all connected properly.

It's time to program the Arduino. You will need to know that the device's function is to tilt the reflector left or right according to the light source. To perform this, note that you will need to make the differentials for the 2 LDR sensors. For example, if the LDR on the left is detecting more light than on the other side, then it will tell the servo to tilt to that light source. It also applies to the other way. If there is an equal amount of light for both sides of the reflector, it should stop tilting, and stay at that position. All of this should be an if statement, inside the void loop. Once you have the reflector tilting according to the light, you can implant the LCD and DHT code alongside it so that the Arduino will run the 2 codes at the same time.

<Top portion>

In the end, you should have a device that will demonstrate the usage of solar tracking, while having a way to show the current temperature and humidity visually. There are many improvements you can do to this device, such as showing the current position of the reflector and printing it to the LCD.

However, as stated, you can use it mainly for solar tracking, and thus you can use this idea for giant solar panels (if you own them).