My name is Sam and I am a rising senior at the Ramaz Upper School in New York. This summer I am building two projects: a TV Be-Gone kit that turns TVs off and sun-tracking solar panels. I chose to build the solar panels that track the sun because I am interested in renewable energy and solar energy. Additionally, I might want to be an environmental engineer when I grow up and building sun-tracking solar panels would allow me to gain some experience in the field. Lastly, I love building and building sun-tracking solar panels provide a challenge that I am excited to attempt to conquer.
Since my last milestone, I built the charging circuit connecting the solar panel to the battery and I wrote the program for the solar panels to detect where it is receiving the most power and to move to that spot. The charging circuit is necessary to avoid over charging the battery and to regulate the voltage going into the battery. In order to prevent the battery from over-charging I used a zener diode and a transistor to divert the current away from the battery when it is fully charged. When the voltage going into the battery goes above 10 volts, the zener diode reaches its breakdown voltage, This means that the zener diode will allow current through it; whereas before the voltage going into the battery is 10 volts it does not let current through. When current goes through the zener diode it flips a transistor to “open”, which allows more current to be diverted from the battery. There is also a voltage regulator in the circuit that ensures that a constant 10 volts is sent to charge the battery. It does this by sending more voltage through the battery when the voltage is too low by taking electrons flowing into its adjust pin. After I completed the charging circuit I wrote the code that ensures that the solar panels find the spot with the best light. I did this by diverting some the current produced by solar panels into the arduino’s analog pin that can read how much energy the solar panels are producing. In the program, the arduino reads how much energy is being produced at the solar panel’s current location, and 10 degrees both to the left and to the right. If 10 degrees in either direction allows the solar panels to produce more energy, the solar panel moves 2 degrees in that direction and repeats the process. If the solar panel is producing the most energy at the current spot it stays in place.
Overall, I had an amazing experience building the sun-tracking solar panels. At times it got very frustrating, but trying to figure out solutions to the unexpected problems that occurred along the way was the best part. More specifically, my favorite part of building the sun-tracking solar panel was trying to figure out how to mount the solar panel to the servo. It took many tries including a nut and a spear (the screw attached inside the threaded rod that resembled a spear), neither of which worked. However, because of the difficulties, it was that much more fulfilling when it worked.
For my second milestone I attached the servo and solar panel to the base and got the solar panel to spin. The servo is bolted into the brackets that I made last milestone. The servo uses a potentiometer that knows the angle is currently at in order to direct the servo how to turn. When the user inputs an angle that he or she wants the servo to go to, the servo spins until the potentiometer reads that the servo spun to the necessary angle. When this happens the potentiometer tells the servo motor to stop spinning. This is called a feed-back loop. Attached to the servo is the servo horn, which is screwed into an aluminum hub, which is attached to the threaded rod using two set screws. As a result, when the servo spins it spins the threaded rod. This was the third attempt at a connection between the servo and threaded rod after trying to use a nut to hold it together and another screw drilled inside the threaded rod and glued in and on the other end screwed into the servo. Both of these did not work because when the servo spun ti unscrewed the threaded rod from the nut or screw. My solar panel is clamped to the threaded rod using two wooden clamps clamped together with screws. Originally, I had 3d printed mounts for the threaded rod to fit through, but they were too big. I tried to use set screws to hold the solar panel to the mount, but the solar panel weighed too much and the set screws would slip. Instead, I decided to use wooden clamps so there would be more surface area touching the threaded rod, so the solar panel could be help onto while the servo spun.
For my main project I am building sun-tracking solar panels. So far, I have completed the base of my project. The base is made out of wood and held together with screws and gussets. Originally, the base was only held together with screws, but the inner pieces of wood were able to spin on the screws. To fix the problem I added gussets, which strengthened the connection between the various pieces of wood. There are two arms that are attached to the inner pieces of wood that can be used to adjust the angle of the solar panel so it can better follow the arc of the sun. In between the two arms is the piece that will hold the solar panel and the servo that will spin the solar panel. I 3d printed in order to ensure a tight fit around the servo that it will be holding. The next step is to attach the servo and the solar panel and get the solar panel to spin.
Code I wrote that will spin the solar panel according to an internal clock in the arduino
For my starter project I built a TV Be-Gone kit. The TV Be-Gone kit uses four infrared LED lights to send a signal to TVs to turn off. The chip in the kit is programmed with a list of signals that different TVs use to turn off and, when the kit is plugged in, it runs through these signals. On the kit, there is a crystal oscillator that keeps time for the chip, so the chip can turn the LEDs on or off at the current time. In order to turn the LEDs on or off the chip flips one transistor that, in turn, flips four transistors that correspond to each LED. The kit is powered by two 1.5 volt batteries. There is also a capacitor that smooths the noise from the battery so there are no spikes or lulls in the voltage as it goes through the circuit. When I tested the TV Be-Gone kit, it successfully turned off TVs even though it sometimes took a moment for the kit to run the correct signal for the TV.