Haven’t done work in a long time, since school started, but I have a few hours of timelapses and I think I should add to the journal.

Basically, I’ve just been working on the PCB, and doing some research, trying to find parts that fit the budget. I think I did a pretty good job, but there are still a few costs that I haven’t accounted for, so I might be in for a surprise later down the line.

Anyways, the PCB is pretty much done, so here are the parts:

• an orientation sensor
• 2x motor drivers(2 channels)
• 3x motors
• battery
• USB-C charger
• Raspberry Pi Pico 2W

I haven’t designed the physical PCB yet, and I still have to figure out the width of the copper paths, since I am working with higher currents.

After I got the basic shape of the PCB down, I started with CAD. I quickly stopped, because the motors seemed too long to fit on the 90mm ball I chose, but, since the angle was 45 degrees, I can just design it so the omniwheel has a 30 degree angle of contact with the ball.

That’s kind of it, but I’ll try to get this project into a presentable form, in order to hopefully get it approved before the deadline.

First steps

Inspiration

I wanted to build some kind of balancing robot for a while, and I thought that a ballbot would be a simple entry into this domain, unlike bipedal humanoid robots or similar stuff. Another big inspiration for me was Tazer, a youtuber who built a balancing bipedal robot to pass his masters. He gave some very insightful explanations on inverse kinematics and inverted pendulums(I have no idea how those work yet) on his secondary channel, and that gave me a push towards starting this kind of project myself.

What I actually did

Since I am awful at technical drawings and putting my own thoughts on paper, I started by first looking for some examples of ballbots, and I landed on this compact design from Navel robotics, that has a feature that lowers the center of gravity, increasing stability.

After I got the main design sorted out, I looked up for a few key parts. I got the IMU from Tazer’s robot, it’s a BNO055. The microcontroller is an ESP32, because I intend to use the Bluetooth function to connect a cheap controller, as opposed to a rc drone remote, because those are extremely expensive(I couldn’t find any cheap ones, if anyone is reading this and has any idea where I could find some cheap ones, comment pls).

Then, I spent some time searching for cheap omniwheels(might have to print my own to stay within the S-tier budget that I’m aiming for), and I settled on a 90mm juggling ball, which is also pretty expensive, so I will look for an alternative down the line.