Diary of a Student Engineer Part 3: SolidWorks Finished, Attachment Design next

Conor Kennedy
4 min readMar 15, 2021


Hi again, I had to skip last week’s blog post as I had other assignments and work to catch up on. However, in the last week or so I’ve managed to make considerable progress with this project. A few check boxes I have recently ticked off include completing the design of all the individual components for the Tumbler, putting together the corresponding SolidWorks assembly and I also had time to build a few prototype home-made ping-pong launchers which I’ll be using to fire a few balls into a container on top of the robot. More recently, I’ve also begun brainstorming designs for a mechanical stabilising attachment for the Tumbler — but more on that next week.

Robot Complete

So, as promised here’s a few pictures of the finished product:

PhotoView render of completed CAD model

Since the last post, I spent most of my time working on the motherboard of the robot. Given the complexity of the custom-made board by Elegoo, I had to make a few compromises so that the CAD model was aesthetically accurate but simple enough so that it didn’t take up an inordinate amount of my time. To achieve this I first did some research into what the key components of the motherboard were for this robot. This in turn, gave me a list of 7 items that if I could accurately incorporate into the design, I felt I would get a satisfactory end result.

The List:

  • LED x2
  • Push Button
  • Ultrasonic Sensor
  • Nano Microcontroller
  • A Driver Integrated Circuit for the Motors (Model: TB6612FNG)
  • A Microelectromechanical Processing Unit (Model: GY-521)
  • An Array of Extra Pins

From this list, I knew I would be able to design the LEDs, push button, extra pins and any extra casing for the components. It was the remaining electronic components that posed more of a challenge. For this, I chose to outsource the most complex pieces from Dassault’s own repository of pre-built components, which you can find here. By incorporating these pieces, I think the robot model conveys the complexity of the motherboard much more accurately than anything I could have created in the span of a week, so I would definitely recommend taking this course of action in future projects (especially where time is tight).

The Motherboard

As for a few areas where this model could be improved; Well the motherboard could be improved on further of course. Some of the more peripheral items, like the texture for the main PCB, aren’t included in the final design for time-saving reasons but obviously would have enhanced the model if it was. Beyond this, I also decided to forego the wiring of the robot for the time being, however if I manage to get my hands on the physical robot in the near future I think I’ll add these in to ‘complete’ the look. Wires are a bit of a funny thing to design in CAD given their flexibility so a tangible model to play around with would definitely help in this regard.

Looking Forward

So, my focus has now shifted from the modelling of the existing robot to the more innovative task of designing a stabilising mechanism for the robot. As the tumbler will have to navigate an obstacle course, it is bound to bump into items that it’s ultrasonic sensor cannot detect and perhaps even get stuck. So, the purpose of this mechanism will be to keep the robot upright at all times and ideally help it get out of any sticky situations it might find itself in, which it inevitably will. I hope to give an update on this by next weekend. In tandem, I will also be continuing work on the ping-pong launcher. This will get a blog post of it’s own but for now, I’ve included two of the prototypes I’ve been messing around with in the last week.

Both designs are based on potential elastic energy

Until next week,

Conor K