Champaign-Urbana Community Fab Lab
Champaign-Urbana Community Fab Lab



This week, we had to make a walking pom-pom bot using Arduino, servo motors and everyday items. When I read this week’s assignment prompt, I knew it was going to be a challenge because I am below average when it comes to conceptualizing mechanisms. So I looked at the prompt and drew the first thing that came to mind. This initial concept consists of two servo motors taped together with one popsicle stick strapped onto each motor (Picture 1). I thought the two popsicle sticks would act like two angled legs. Will it work? ¯\_(ツ)_/¯

Picture 1



It didn’t work (Video 1). The bot stayed in the same place, chopping around. At this point, I wasn’t sure what I needed to change to get it to start moving its position (because I also generally suck at physics). I looked at my friend’s bot (which was going places!) and I noticed her motors were turning very fast. It also had shorter popsicle “legs.” I then noticed that my “legs” probably needed to turn more. So for my second prototype, I decided to cut half the popsicle legs off, set the servo motors to turn faster, and set the motors to turn for a greater number of degrees. The plan was to propel my bot forward using momentum. Increasing the speed of the motor through the code wasn’t a problem. You can see in Video 2 that the updated pom-pom bot design/mechanism is an improvement from the initial design because it’s slowly going somewhere. In my head though, I thought my pom-pom-bot was going to move forward a lot more because of the alleged momentum.

I also added some decorative feathers and googly eyes to give my pom-pom-bot some personality.

Video 1


Video 2



For my final pom-pom bot (Video 3), I really wanted to keep trying for that “momentum” action. I added an additional, short, popsicle “leg” on each motor. This leg is positioned between the arc of the two legs. I thought it might help with the push forward by giving the bot a bit more arc from the ground. I also changed my code so that it would iteratively push forward quickly and retract slowly. The final bot’s movements weren’t as symmetrical as the bots from the 1st and 2nd design, but this third bot certainly went farther faster than both of the previous bots. Because I didn’t want to use too many materials or take apart my first and second bots, my redesigns were relatively simple part additions or subtractions to the bot. For that reason, my final pom-pom bot looks a lot like my first design, but with a few extra legs and flair.

I wasn’t sure how to code different motors to go different speeds/positions at the same time. At the time of the project, this wasn’t essential to my pom-pom-bot design so I admittedly did not google a fix to this curiosity. If I wanted to improve or redesign my bot, I would probably have three or four motors, and at that point, I would definitely have to be more precise and strategic with the coding.

Video 3