On 2.00Gokart; Or, Designing a Design Class to Disrupt Design Classes as We Know It; Or, How to Make MIT Undergraduates Build Silly Go-Karts so You Don’t Have To

I think I’ve promised a 2.00gokart “total recap post” after every session of it so far. This is a piece that is long overdue on this site, and in all honesty, probably also way past its time to present in a more formal venue. Edit: It’s now on Make Blog! Thanks Make! For the past now 2 years and four sessions, what I consider to be my most long and extensive project has been developing quietly in the halls here at MIT – that is, as quiet as the high-pitched whine of square-wave commutated brushless airplane motors can get you, anyway, interrupted periodically by the interdiction of concrete-backed drywall upon metal; facilities and my space directors will never let me live that down.

I’m two months late and running from when I first said to expect a wrapup of the summer SUTD special session I ran for their visiting students.  What this post will be is a ton of writing. Interspersed with as many photos and references as I can manage, of course, in my usual style of discourse, but most of it will be me waxing poetic – and perhaps polemic at times – regarding my own motivations to start this course, experiences in running it, and ultimately what my end goals are and where I want to see this class end up.

I anticipate this post being extremely long. In fact, so long that I’m going to split it into multiple sections ahead of time. What will be presented from here on is basically a much more concise, casual, and perhaps more profane and offensive version of my original Master’s Thesis, minus most of the the graphs and tables (because every Master’s Thesis in engineering needs graphs and tables, for whatever reason), and with more pictures and videos. The first two parts essentially amounts to me ranting, and the second half is the productive info, followed by more despotic proselytizing.

Here’s the table of contents: First, a summary of my motivation for making the class. Next,

  1. A brief rundown of my own history with engineering projects and how that both aided and hindered my academic performance at MIT
  2. How I took an interest in teaching and why I saw issues with the current system of design classes
  3. A history of my involvement and leadership in the electric vehicle design realm
  4. Recap of the 2012 class “2.00scooter”
  5. The changes made for the 2013 class “2.00gokart”
  6. The 2013 summer special session and the changes made for it
  7. Where the class stands now; content, procedural, and logistics.
  8. What I think the class brings to the world of design classes that is different or novel.
  9. More about the resource base of the class and the cost of running
  10. An SAE Asston (like an ISO/DIN Arsetonne) of lecture notes, resources, and links I have built up so you can run your own silly go-kart class

Read more “On 2.00Gokart; Or, Designing a Design Class to Disrupt Design Classes as We Know It; Or, How to Make MIT Undergraduates Build Silly Go-Karts so You Don’t Have To”

Loose Odds and Ends from the Past Week or so

Things have been getting exciting in the last week or so as the SUTD Summerkarts Global Leadership Program students have arrived, and we’re now well under way into the Silly Vehicle design phase all over again. Global Leadership Program. That’s such an epic name for 2.00gokart, guys. To be fair, there’s plenty of other things going on for the students too, most of which are ‘leadership’ flavored. In this running of the class, since I’m not being watched over by The Department and need to make sure everyone has paper lab notebooks, the student groups will be blogging their builds! I’ll post a list of links once everyone gets set up.

mikuvan

I’m currently at 380 miles.

Having essentially reached the limit of things that have been going wrong, I’ve been faced with no choice but to start attacking rust. This thing hasn’t even so much as hiccuped a single time since Operation: Bad Timing. I would say that at this moment, having checked everything I think is important, I’d trust a trip out to at least New York City (about 240  miles).

I’ve mostly been spending the past 2 weeks psyching myself out and picking up some materials.

 

Based on estimating the clooooouuuuuud Internet and asking friends, I got a pile of things from Eastwood – panel sheets, a bucket of sealer, and some rust converter. I was skeptical about the “rust converter” – it allegedly converts iron oxide (“rust”) to iron phosphate or iron tannate, which is some shit I’ve never heard of and only appears in product descriptions plagiarized from Wikipedia. This sounded shady, and success seems to be hit or miss. However, it’s relatively cheap, so we’ll see what this magical potion does. That, plus another haul of random abrasive and sheet metal banging tools from Harbor Freight, ought to round out the basic non-sketchy rust patch. I’m going to try the pound-and-weld-metal route – falling short of soldering since it sounds a tad too hardcore at the moment – instead of throwing fiberglass at it.

All that, and waiting for several days of hot and dry weather to do the majority of the work, just to smoke out any residual moisture from the body holes. Recently, it’s actually been hard to come by, with the Northeast in its Periodic Random-Ass Storm Season (PRASS). There’s no point in tying a puddle up inside my work. Worse come to worst, I’ll point a space heater at the trouble spots for a day before doing anything.

What I’ll do first is probably do all the sanding and grinding; the full-depth investigation, basically, and then post it publicly to get some opinions and appraisals. The idea is to cut or grind off what I can get to, covert and cover over what I can’t abrade off, and then slather external underbody repairs in sealing compound. I also managed to find a matching Chrysler color at Advance Auto Parts to repair the exterior paint afterwards, tested by blasting random areas and staring at it a few minutes later. This may backfire horribly.

Part of the reason I’m hesitant to start is because I have the feeling that things will get more and more Death Race 3000 if I mess something up or discover more structurally unsound areas than I previous anticipated. What you can’t see….

Though, in the limit of Death Race 3000 style modifications, this thing will probably look more and more like a classic wedgebot.

testing the mini-jasontroller

I replaced the full-size caseless Jasontroller in RazEr REV2 with the mini version detailed last week.. I’m definitely a big fan of these now – they’re basically the same as the full size, in a much more useful package.

This is the smaller controller uncased and fully cleaned. I essentially took out every wire I didn’t need, and also locked the speed setting to high internally by jumping the right side orange wire; by default, the “3 speed range” switch comes in the medium range, which means it divides down the throttle input) This has no bearing on its upper speed limit which is still around 540-550 eHz or so, but for low speed motors the throttle response will be substantially retarded otherwise.

These controllers have a discrete logic power switch, unlike the full size Jasontroller, so I also hardwired that internally (left).

I discovered that the entire controller case fit inside the space where my old full size Jasontroller went, minus one corner. So, instead of redrilling the mounting holes for the smaller heat spreader bar, I cut the entire case into an L shape with the board resting in its stock location…

…shrink wrapped the whole thing, and Velcro-mounted it in. Clean and waterproof, and the additional aluminum should still offer some thermal capacity.

The overall height of the controller when stripped of its case is under 0.8″ (in my configuration, it’s not much shorter due to the existing case outline remainder), which opens up the potential to be stuffed into even more things.

I’ve noticed no difference in riding behavior between the mini-Jasontroller and full size, once again confirming they’re basically the same thing. I’ve noticed some slight difference in starting behavior – the mini doesn’t twitch backwards, at least not often. More observation will be needed to discern the differences. In the mean time, I’m officially qualifying the mini-Jasontroller as Certified Legit. You can buy it on this page, and maybe soon from Equals Zero. If you make something using one, post it!

I’ve added this controller to my Scooter Instructable in the EV controllers section.

more silly rideable things

One of the downsides of having 160 cubic feet of self-motive cargo volume is Oh man, this free stuff on Craigslist looks awesome. I’ve previously been limited by what I felt like carrying back on Melonscooter, or worst case, ride back independently. That’s no more.

What you see here is a most-relevant-to-my-interests free Craigslist haul of two nonfunctional electric bike (-like-objects) from a closing e-bike shop. The one on top, as it turned out, is quite the machine. It’s a TidalForce IO cruiser bike, from another one of those small EV companies with an illustrious but ultimately short lived existence, in complete condition. The bottom red pile is a generic Chinese “电动车” or “Chinese moped”. These are sold here and there under various names (here’s one example, and most likely the company that retailed it since it says GREENPOWER on it!). Its condition was a little more beat up, but seemingly just devoid of batteries.

Here’s a better shot of both of them. Being me, I’m actually more a fan of the little red moped – it’s a little weirder and has that Chinese charm to it, but the Tidalforce was much more complete, so I began messing with it first.

The backstory of this machine was that the customer dropped it off for battery service and abandoned it. Apparently, these bikes were notorious for having their NiMH cells degrade very quickly.

Lacking a legitimate charger, I jacked it in on a power supply to 45 volts CV and fed it at about 0.8 amps for basically the better part of a day. The cells inside are nominally 8Ah, so the charge rate is a nice C/10 trickle charge. In case any of the cells were permanently toast, it wouldn’t cause thermal runaway. The battery came off nice and warm, and I rode around until the bike shut down from undervoltage. This charge lasted basically 5 miles with very little pedaling. The original advertised range was 15 or 20, but according to the storytellers realistically 6 or 8 miles, so it didn’t seem that far off the mark.

The termination condition is dictated by the battery management system onboard, and this is where things got difficult. No matter what, I couldn’t convince the charge-o-meter to go above 20%, even when I’ve clearly left the battery on slow trickle for many hours! I suspected that this artificial BMS meddling is what shut the bike down in the first place, since it didn’t feel like it was about to slow down.

I did some research online and came upon this useful page for decyphering the onboard controller for the bike, as well as this flamewar thread on Endless Sphere where someone mentioned that the battery needs to be discharged to under 32v to resynchronize the charge indicator.

This battery is too damned smart. I couldn’t get any output voltage from it unless the bike was on, since it has internal FET switches to shut off the cells from the pack output, so I couldn’t artificially drain it. And even at 44 volts off the charger, I couldn’t get the bike to move more than a couple dozen feet before the BMS shut me down. I hate it when batteries are too smart – I’m forced to crack them open.

Off the front wheel comes. It’s on a quick release, so a latch and some cable pulling later and it comes cleanly off.

Removing the case screws and side, check out this holeaphobia-inducing lotus flower of cells! The terminals all had bits of corrosion on them, but there were no signs of leakage that I could observe.

Hammering on the opposite side of the wheel makes the entire battery structure fall out. This is the important side of things – the BMS board. My mission was to artificially brick the pack via the CELL tabs, draining them to under 32 volts, hoping the BMS would reset or something.

I used this shady arrangement of power resistors, totalling 15 ohms, to drain down the pack over the course of about 3 hours, getting the whole array down to about 30v. Afterwards, I immediately closed everything up and threw it back on the charger. It did exactly jack shit.

The battery meter blinked 20% the whole time! I’m going to guess I did this wrong somehow, or more likely, forgot that Ni batteries bounce back in voltage very well after an initial discharge. By the time I was done connecting things back up, the battery voltage could have been well in excess of 32v, making the BMS think everything was still skullfucked. But it should at least recognize the 7Ah I dumped back into the battery, right?! No such deal.

As of now, I’m currently riding this thing around day to day to burn down the charge in a useful fashion. Apparently, the charge meter blinks in its entirety when the BMS reset point is reached, so I’ll hopefully be ready then.

Why am I trying so hard to use this proprietary-ass stock battery when I could very well just hack the “B” battery with any number of potential long running packs? I’m hesitant to do that because I don’t actually like this thing. It weighs nearly 60 pounds and is enormous, clearly built for a much Manlier Man than I. Plus, I can barely stuff it inside my front door. I guess I’m used to smaller and more portable scooters which can be rolled inside – this sucker is going to need the bike rack. Not really my style.

For now, though, it’s alive and working as yet another Craigslist impulse that turned out to be a little neurotic but otherwise livable day to day. What’s with me and that kind of thing lately?

Let’s move onto the Little Red Moped.

After diddling around with the TidalForce for a few days, I decided one night to get this contraption running along with Adam. I cleaned up the mechanicals and repaired the existing wiring while he created an impromptu brick of 12V7 modules I have on standby for the summer EV design class.

Look at that beautiful… 20 gauge? wire going to the hub motor! This machine is capable of Real Power.  The hub motor appears to be a 48v, 500W (or 750W) brushless type, like this.

Unhitching the electronics box, I discover this wad of wires. If you ever wonder what Jasontrollers and their ilk are actually used for, this is the answer. As you are reading, millions of Asian moped bros are cruising about on machines exactly like this one.

During my wiring cleanup, I found a spider!

Someone clearly was derping around with this after-market and the controller is likely not the original. Someone was also terrible at this. There were plenty of examples of wires just twisted together and electrical taped up, and solder joints like that.

Whatever. It worked, and all I really did was replace some of the decomposing electrical tape and resplice some of the signal wires appropriately.

With the impromptu 48v battery and a random found bike seat, it was ready to roll!  And roll it did. The acceleration was brisk and utilitarian, and the suspension was a bit underdamped but compliant even when riding up curbs. It’s very quiet, and there’s a pedal assist sensor which almost sent me into the wall a few times when I instinctively kicked the pedal out of the way.

Riding it in this form makes me envision myself wearing a straw hat and dark brown Mao suit, riding along a dusty Chinese road to my factory job. With a cage of chickens on the back to be sold at the market later that day.

We agreed it would be more amusing once completely rewired and running on 72 volts, but sadly, Mao’s Little Red Moped did not see that day. For at Swapfest, I was riding around aimlessly for no more than 10 minutes before someone bought it off me on the spot. Sans batteries, but still.

So my net wheel gain for the past few weeks has been 2, both won by the TidalForce bike. Unfortunately, that may increase again, because I’m considering…

a playmate for mikuvan

Your job, Internet, as the guardians to my sanity, is to tell me I do not need another one of these.

Let’s face it. I was originally looking for a science project with Mikuvan, but elected to put in an honest repair effort to have me some of that thar “auto tech” larnin’ y’all kids are into these days. But now it’s running too well, and a few of us are basically invested emotionally in it, and I have a harder time with the thought of tearing everything down again than when it wasn’t running.

Mere weeks after I stated my life goal Passive Non-Career-Derailing Desire was to collect the Legendary Van Trifecta, I discover that I might have a chance to nab the rarest of them all: the USDM Nissan Vanette. Yes, the one which was well known for lighting on fire.

The back story for this find is quite circuitous indeed. It wasn’t by weeks of stalking Craigslist, or a “Hey, I hear you like derpy vans” referral from my “Hey, I heard you like trashy electric scooters” network. Instead, while doing research on the other members of the trifecta, I found this Jalopnik post for a Nissan Van (-shaped-object) in North Carolina. Some link hunting led me to the original sellers album…from 2011.  Out of sheer shits and giggles morbid curiosity, I emailed the seller what amounted to “lol do you still have this”. MFW the answer was yes:

I’m at a loss about what to do.

On the one hand… Whoa, a chance to capture the rarest Legendary Pokévan and train it make it the base for this electric drive project. After all, the way the world apparently works, as I’ve handily found out in the past few months, is you have a functioning car, then you get an explicitly nonfunctional one to mess around with. This van is so explicitly nonrunning the FCC and ASE are about to join forces to erase it from reality. The chassis mechanicals appear to be comparatively rust free (then again, so I thought with Mikuvan).

The downside? Space. Parking. Not even counting the (once yearly) cost of registration and (fairly low) monthly insurance premiums once it’s operational, there’s no such thing as a little empty grassy patch to stick a nonrunning vehicle here. I was lucky with Mikuvan that my one allotted parking spot was open. What I cannot justify is paying hundreds of dollars a month for a parking spot or garage space for a van-shaped lump without the knowledge that I will immediately be able to attend to it, rare or not.  I’m currently in the process of exercising my social network™ to see if anyone is willing to put up with my bullshit. Ideally, there’s a back alley of a nearby industrial space somewhere that I can slip into, or someone’s back yard who thinks this is all too hilarious. I’m not going to try very hard.

So the dilemma goes. I will probably not see one of these in such a complete condition for many years, but maybe in said years I’d be in a better position to start Big Chuck’s Van Adoption Service.

 (All pictures above of the vehicle were provided by the seller)

I’m filing this post also under Beyond Unboxing since so many things were taken apart in one way or another.