Arduino Pom-Bot


For the in-class project I used one servo motor to create a simple flower in a pot. I cut a hole through the back of the cup to feed the wire through and created a flower to attach to the motor arm. The trickiest part was making sure the motor stayed put inside the cup while moving, which I ended up resolving by poking two holes through the bottom and fastening a pipe cleaner around the motor. The final result can be viewed here: IMG_0530

Getting the final project off the ground proved much more difficult in comparison. After getting some help from my roommate in ECE, I managed to successfully hook up the two servos. I originally wanted to try making a fish or snake-like robot. My attempt to create the skeleton of it consisted of stringing a pipe-cleaner between two servos, but after doing some further tinkering and research it turned out that more than two motors would be needed, and I have no idea how to easily replicate simple harmonic motion in Arduino code. Therefore I ended up scrapping that idea.

an example of a failed attempt

I kept trying to come with ideas, but many of them didn’t work. The ideas made were not based on the objects that were actually created, but rather on how I could program the servo to make it move. For some reason I really just couldn’t come up with a way to make the object move, even though I understood that the servo motion could not be symmetric and one motor had to be stronger or have a wider range of motion than the other in order to propel the object in a direction.

I finally just tried going through with a standard toy robot. The image to the right is not particularly descriptive, but basically the idea was to put servomotors into each leg, connect a long bar to the servo motor arm and leg interior, and the motors would simple rotate between 0-45 degrees to move one leg in front of the other. The code for this was pretty simple, just two for loops oscillating between 0 to 45 degrees and writing the angle to the two motors. I used the Arduino online IDE to edit and push my code to the board.
 I only had brown cardstock lying around at home, so I used that to create each leg; the connecting rod between the motor arm and the cardstock is a pipe-cleaner twisted around the motor head. Overall the idea was pretty simple; however as seen here: IMG_0533 there were some issues getting the leg to move. Throughout the whole project my greatest frustration with the motors was that fact that often they were too weak or light to move the object attached to their arms, but rather the motor bodies themselves would move X degrees relative to the object. So as you can in the video, if the leg was resting on the table it wouldn’t move; the motor would just rotate on the inside of it. Even when I tried connecting both legs, neither of them would move: IMG_0535. I couldn’t think of a way to weigh down the motors such that the object would move relative to them instead of the other way around.

As you can tell, the last hyperlink is the closest thing I have to a final product and it’s not finished. However considering the large amount of time already taken to get this much done I decided to go ahead and submit what I have. This project was actually pretty frustrating in that I just kept seeing none of my ideas actually work, and working with the servos was tedious as well. Often I had to keep “zero-ing out”, ie. resetting the motor head to zero, in order to make sure I had the correct start and end points for the motor’s range of motion. And as mentioned, I couldn’t figure out a way to get the whole objects to move as I had envisioned them. From this project and the previous Arduino unit I was able to learn how to use the Arduino IDE and work with basic hardware. But it’s convinced me.. I think I should stick to software hahah.

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