Turtle History
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Back in September 2019, I quit a robotics teaching position because of pedagogical differences. I wanted to have some artifact to do the things I argued for: student agency, mathematical reasoning, student engagement and attitude towards computational thinking. I was still high from my semester at UC Berkeley and (still) obsessed with Mindstorms, I was thinking about how I wanted to teach mathematics and geometry for my upcoming student teaching semester. Wow. How cool would it be for my students to work with TURTLES and all the ideas presented from the book and in a LOGO environment?! I searched extensively for a cheap solution for this. After some searching, I couldn’t find anything that would be cheap to buy in bulk or that was up to date. I then made the decisions to make my own! This 3D printer’s gotta be useful for something!
I started chatting with some people who might be able to help me with the engineering things–I didn’t know squat about CADing, 3D Modeling, electronics, etc. I was just a nerd that could do some coding and was obsessed with Seymour Papert. I brought the idea to Daniel Leung as well to see if he was interested in collaborating. To my surprise, he was already thinking about ways for kids to interact with electronics and coding! He took me to his office and showed me his giant stack of micro::bits and alligator clips and some other things.
*"I've been wanting to do something like this, but I haven't had the time to play around yet!"*
I had Lucio Moreno and Jasmine Heer talk through some of the mechanical engineering stuff with me. Lucio helped me out with drafting some of the CAD stuff on Autodesk Fusion and Jasmine helped him out with measuring out some things with a digital caliper. I learned what those are. They are pretty handy.
Meanwhile, I started learning how to code with the micro::bits. I did a few quick projects, but quickly realized that I needed a driver board to connect the motors to the board. Daniel and I looked at a few online. I decided to go with the Keyestudio Motor Driver Board. The cost was low and had what we need. After that shipped, I started looking at how to control motors through the micro::bit code. Results were pretty disappointing.
I didn’t have enough voltage! (I didn’t know this at the time, so that was pretty frustrating.) The board needed 6V insetad of the 3V I was giving it. The micro::bit was able to run with the 3V, but the board needed 6V to power the board and the microbit at the same time. Dang. Being the idiot I was, I started looking for 6V batteries and ended up ordering battery packs of 4 (1.5V each). I ended up taking my whole shindig with me to my Circuit Theory lab and used their power source to test out the motor. Got a lot of strange looks when the tiny motor screeched because I fed it so much juice.
After taking it home to show my roommate, Jeffrey, he asked why I couldn’t just put the batteries in series. Dang.
I found out how to also connect a servo so that we could move the pen up and down. Fun fact, the orientation of which way you plug the servo in matters…..
Daniel mentioned that he’d like to have this project in an after school program that he taught at his son’s middle school, McSwain Elementary/Middle School in Atwater. I realized that we could probably do some research on this! I met with Ahmed Arif from UC Merced’s HCI Group. We met for and I told him that we could probably get this thing going in a few weeks!
I printed out some of the CAD files that Lucio made. Here’s what we’re looking at in November:
Things started to get hairy because everyone’s schedule became hectic and unpredictable–finals and all. I had my CalTeach portfolio due at the time too. The project was placed on a brief hold while I was trying to get my life together and Lucio also didn’t have enough time to finalize his CAD drawings.
I was running into some issues I wasn’t sure how to debug. Hardware is hard. I had set everything up so that my Turtle would drive, but my wheels would vibrate in place most of the time. I had some balancing issues where the weight on top was not evenly distributed, so one side of the body would always tip over. There were a million factors that could be going wrong here.
I suspected it was a problem with the tiny wheels. We suspected it was a problem with the tiny motor. We suspected that the batteries weren’t giving enough voltage. We suspected a LOT of things and we tried many different things–I wish I had logged them all out. The wheels would spin fine if we lifted it off the ground and ran it, but it didn’t have enough power to overcome the static friction, is what I thought.
After walking up “the hill” one day, I ran into an old friend from Merced College, Daniel Milliate.