Hi, I’m Muto.
I work as an engineer building web systems for companies, and at RumiCar I also teach the programming workshops.
This time, though, I wasn’t teaching. I signed up as a participant and went along to the RumiCar chassis-building workshop.
Same RumiCar community, but a different subject. Instead of programming, the whole day was about building the car itself — soldering iron in hand, wiring things up, putting the body together.
From the front of the room to a seat in it. It had been a while since I was the student, and I’d forgotten how much fun that is.
It starts with a soldering iron
For anyone meeting RumiCar for the first time: it’s a small self-driving car you program yourself. There’s a row of laser distance sensors on the front, and your program decides how the car should drive based on what those sensors see.
What we built this time was the stage all that code eventually runs on — the chassis.
Solder the components onto the board, run the wiring, assemble the body. One sentence to write; quite a lot of things to actually do.
I melted a part almost immediately
And then it happened.
I held the iron slightly too long, in slightly the wrong place, and melted one of the parts. The melted section deformed just enough that it would no longer fit where it was supposed to fit. At all.
I’ll admit I went a little pale.
But our instructor took it, said “this is fine,” and repaired it beautifully. It fit again. Thank you, really.
I also singed my bangs that day. I’d leaned in too close to the iron, and the smell that followed was something I won’t forget. If you have long hair, please tie it back. I’m serious.
Lattes in hand, and completely absorbed
That probably sounds more stressful than it was. The atmosphere in the room is actually very calm.
People work at their own pace with a latte or a coffee next to them. Conversation drifts along in the background. On the whole, it’s relaxed.
But glance down at anyone’s hands and you’ll see total concentration. When you’re working with parts that small, you just naturally stop talking. That combination — quiet on the surface, intense underneath — is one of my favorite things about this workshop.
We had someone join online this time
One of the students joined us remotely.
For online participants, we ship the full chassis kit out ahead of time so it’s waiting on their desk. On the day, they work through it with the instructor over video.
This particular student builds custom keyboards, so soldering wasn’t new territory. That experience showed — they moved through the build without much trouble, screen or no screen.
Our other student hadn’t picked up a soldering iron since middle school. There were some tricky moments, as you’d expect, but with the instructor’s help they finished their build too.
The instructor checks in constantly
The best thing about this workshop is that the instructor keeps asking, at every stage, whether it’s safe to carry on.
With soldering, the later you notice a mistake, the more painful it is to undo. So you go a little way, get it checked, go a little further, get it checked again. Thanks to that rhythm, nobody had to tear down and start over.
The online student got the same treatment through the camera, checked at every milestone. It turns out distance doesn’t change much about how closely someone can watch your work.
Then we all went looking for a flying part
This was my second chassis build, so it went more smoothly than my first. Simply knowing what’s coming next takes a surprising amount of pressure off.
That said — things happen.
I was trimming a part with nippers when it went snap and launched itself somewhere into the room. A part we needed.
Cue the search party. All of us on the floor, peering under desks, hunting for one tiny piece of plastic. Everyone staring at the carpet together. Another moment that only happens in a room full of people building things.
We also discovered that our online student was short a few components. I delivered the missing parts in person a few days later, and I’ve since heard that the car came together properly. Good news all round.
And it drove
The student who was there in the room finished the assembly, flashed a program onto the CM, and got the car running on the course.
Watching a car you built yourself drive away from you — that one never gets old.
All in, the day took about six hours.
That may sound like a lot. It went by fast. And when what’s waiting at the end of those six hours is your own car, moving under its own logic, six hours is nothing.
Once it drives, the rest is down to the program. How close do you dare hug the wall? When do you start the turn? How much speed can you carry through it?
From here on, write your own logic. A chassis you built, running code you wrote — at that point it’s completely, unarguably your car.
One last thing
I melted a part, singed my bangs, and crawled around the floor looking for a component that shot across the room.
Not the most dignified day I’ve had. But somewhere in all the laughing and fiddling, a complete car appeared on the desk in front of me.
Getting it wrong costs you nothing here. The instructor will always step in, and the person next to you will get down on the floor and help you look.
If anything, the parts that went wrong are the parts I now enjoy telling people about.
“Haven’t soldered since middle school” turned out to be fine.
“Joining from home over video” turned out to be fine.
All you really need is the urge to try it.
Hope to see you there.
RumiCar links
- connpass (all events): https://rumicar.connpass.com/
- Facebook group: https://www.facebook.com/groups/rumicar
- GitHub: https://github.com/RumiCar-group/RumiCar
- YouTube: https://www.youtube.com/c/RumiCar