The Chair

It works. I attached the drivetrain fully and then (not tracked oops) programmed a very simple mock control program and put it all on one brain (not final design). I no longer have access to my school as my job ended, I’ll finish this project when I come back to school in early August. I plan on (1) fixing the height of the drivetrain so it actually presses into the floor enough to drive smoothly, (2) reinstalling wheel and programming it for self driving, (3) final tweaks for stability

I got the drivetrain basically done

kinda dumb but I built the drivetrain and now I realize the gear is bigger than the wheel so it won’t move oops

Working on drivetrain now I also programmed the rest of the chair with a few safety settings so nobody gets hurt!

Re-added steering wheel with much stronger support bars and a shallower angle with a lower placement that makes it easier to see over and more comfortable to grip. I added the battery and a license plate to a new crossbar in the back.

I took off the steering wheel so I can fix the wobble later, I am keeping that module though but extending the bar on the seatbelt thing

I switched this to a hardware project so I don’t have to use lapse anymore. I lost 4 hours today !! :|

Anyways, I added the steering wheel today. It holds (kinda) well and it will (should) not fall off.

Uses a Yoke design with a screen for HUD statistics like km/h and each node’s battery life, will program this later today. HUD will also be used for “ignition” and the unlock procedure. Considering using an SD card as a “key” for the “car”. The buttons on the wheel represent forward/reverse although I may want to make that it’s own gear shifter on the side and use both buttons as a forward (you have to click both, for saftey) I will also need to add the E-Stop somewhere.

Excited how real this project is becoming!!

Up next: 3D Printing a support bracket for the wheel bracket so that it doesn’t fall tf off anymore. (ribbed setup on the angled piece)

oh lord i forgot to make a devlog again…

anyways throughout this time and many timelapses I have fully programmed the steering wheel code, it has a full resistance turning wheel that is based on a motor + its encoder. it uses the angle to determine what direction to steer and the wheel speed to determine how much force it adjusts back to the center with like a real automobile

also I added a new bracket that mounts to the bottom of the chair with some drilled holes, this removes all wobble

moreover, I added the steering wheel / front brace / steatbelt bar that falls down over you so you can grab the wheel and not go flying out (see fig. 1)

room empty as week 1-2 kids no longer stay until 3rd and 4th period, however I now have much more time as my 4th period doesn’t exist anymore and I can grind for 2 hours minus my lunch time.

That’s all folks, more updates coming soon. Hopefully, I’ll try to remember to post them this time.

Started working on this old hunk of junk again.

Me and my very technically literate friends got this idea at the start of the year. When we first entered the PLTW lab for the first time, we saw the chairs had wheels. Like a lightbulb, it clicked in all of our minds that we wanted to make a go kart…

We didn’t work on it much, we snuck in during lunch freshman year but eventually the teacher in that room made us take it apart because we “were destroying school property” or whatever. To me, you just don’t like to have fun :(

However, I’ve recently restarted. My friend group has recently been employed at our school to teach robotics to smelly middle schoolers over the summer (dude I thought me saying 67 was bad, GET A LOAD OF THESE GUYS). Together, our schedule has 2 free periods (as well as lunch) out of our 4 period day to do whatever in the PLTW room. Since we self-moderate ourselves and have our own keycards, we truly have free will to mess around with anything and everything. Currently, there is at least one Xbox from home and 3 computers loaded with Roblox on the DAILY. Overall, it’s just really nice being with your friends at school without going to school…

Some of the middle schoolers like to stay in there during break/lunch to mess around with the parts, so I can’t lapse it during then. However, during my extra time, I am working on the chair or homework for my 4th period (pfft, I’d rather do the chair, its cool asf)

To begin with the actual devlog, the chair part of the chair is a Rio 2 4-Leg Armless chair from SitOnIt Seating. It has an angled bottom with 4 screw holes – perfect for mounting something.

Firstly, I dug up the old CAD files and trashed all of them starting from scratch. I took some measurements and 3D printed a new bracket for the bottom of the chair. Before, I just bent a piece of metal; but this time, i’d like to actually have something perfectly angled so it’s flat with the floor. I used Fusion 360 for all of my CAD work.

In CAD, I designed a left and right armrest as well as a bar + some ziptie locations to keep everything stable (note, none of this was tracked. Moreover, I did some quick planning with ChatGPT to find an optimal drivetrain configuration. We settled on 200RPM with a 72:48T gear ratio (72T on motor, 48T on wheel) with 4 motors per side of a differential drivetrain for a total of 8. Some quick numbers: 24.8 lbf push forse and 3.57 mph, reasonable for a small vehicle but not a death kart.

.. and then stardance started.. YUP! None of that work was tracked!! YIPEEE. Now, this is what I did in the 1h 28m:

Afterwards, I began work on the actual construction.

First I bolted on the bracket to the 3x C-Channel main bar. I then screwed it onto the chair and OOPS we need to drill some holes because my measurements were way off (screw you, old dial caliper.. or maybe I can’t read it idk).

I built the left and right armrest models in real life in the PLTW room at my school. (lapsed)

I then put them onto the bracket (lapsed)

.. and finally, I built the motor frame for the left half of the drivetrain.

That’s all folks, I hope (and am on track) to finish this in under a month, which is good because my summer school ends in 3 weeks..