Houseplants bring the beauty of the environment inside and are shown to improve human heath. However, plants often have trouble growing indoors due to irregular sunlight patterns. To optimize a houseplant's ability go grow inside, I created The Phototrobot, which is an autonomous solar panel powered robot that follows visible sunlight. By powering The Phototrobot with renewable energy, I'm utilizing the similarities between plants and solar panels to protect the natural world that my robot brings indoors.
The Phototrobot was originally inspired by the Rumba robot. I wanted to create a robot that was circular and close to the ground because felt this specific shape would make my robot minimally intrusive while still aesthetically pleasing. Additionally, I was inspired to implement a sunlight searching program because of the Rumba's existing search functionality.
I later became inspired by rotating solar panels when I began thinking about adding an environmental aspect to my project. I've studied solar panels in the past and learned that specific products exist that rotate them to the most efficient angles based on the time of year. Since these mechanisms are very expensive, I wanted to take the idea of adjusting solar panels based on the current sunlight and scale it down to a smaller robot.
I began thinking about how I could combine solar panels and plants on top of a small robot. Since solar panels need a lot of surface area to be effective, I wanted to tilt them so I could fit more within my confined area. Since I know that in Massachusetts solar panels work best at a 45-degree angle, I thought tilting my solar panels was a good decision.
I originally wanted to make my solar panels and plants modular, with two different types of components that could be customized on top of the robot. However, I then moved to making five pieces that hold both solar panels and plants so that I wouldn't have to think about complicating the wiring with so many removable pieces. I ended up scrapping this idea when the solar panels were shipped because I realized that the sizing I found on the internet indicated that the panels were much larger than I originally anticipated. I changed the orientation of the solar panels so they would fit on my robot and began modeling one piece with these constraints.
I also began thinking about how to transfer the wires from the solar panels through all the different layers of my robot. Since the top piece of the robot was originally intended to spin, I wanted to keep this capability and integrate wires that were able to spin with a mechanism called a slip ring. Because of this, I designed a couple different pieces I could 3D print to integrate the wires through the spinning part of the robot.
Once I made these design decisions, I began editing the original version of The Phototrobot from a previous studio. I wanted to keep some of the design elements that I believed worked well the first time. Specifically, I wanted to use the wood filament 3D printed pot idea and the flexible wood piece for the outside. I kept these parts of the design and started integrating the changes I'd begun to plan.
I experimented with my modular plant and solar panel holder, the singular solar panel and plant holder, the slip ring holder, and designs for the top piece of the robot during the first couple weeks. After finalizing the designs, I moved to assembling the whole robot.
As the construction diagram shows, The Phototrobot has three main layers: the base layer that attaches to the wheels, the center layer where the sensors are housed, and the top layer that's visible. On top of this layer, I attached the solar panel holder and the planter that fits into it.
Once I finished the construction, I began the wiring so the robot would execute it's intended function. I wanted the robot to turn towards the sun when the front wasn't facing it and move towards the sun once the robot was oriented correctly.
The wiring contains two circuits: the solar panel charging the battery and the sensors giving data to the Arduino so it can set the wheel motor rotation and speed correctly. There are five sensors that track the light in a circle around the whole robot that are all wired separately to the Arduino for five streams of separate data.
After wiring and programming the robot, I put all the pieces together to get the final product. Overall, the simple design of the project masks the complex circuitry and mechanisms on the inside.