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pst

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    Detroit, MI
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    Electric vehicles, alternative transportation, cycling, ham radio, drones, radio-controlled cars, and a few other nerdy hobbies!

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  1. pst

    Open-source EUC motherboard

    Exact quote of mine from the 2018 thread: "I have decent ability in firmware (and hardware) but unfortunately not a lot of spare time due to work. Still, if you have a good understanding, let me know and maybe I can help." So, anytime people are ready to get something together, let me know. I am a little lean on the control theory but my degree is in SW, and I've spent several years building "embedded stuff" (SW and basic HW) for various employers. No matter who does what, like I said in @KuphJr 's recent post, I would really suggest coming up with a well-documented design which is hardware-agnostic first. And that certainly does not require C knowledge.
  2. pst

    So glad I found this forum!

    Welcome to the group. It might help to have one "introduction" thread, and then a second about the project (or you could add to one of the existing related topics). There are a couple threads floating around about related ideas... the one above about a controller, and another about building a whole wheel: Like I say in that thread, I am happy to help out with some such project too, though my time is (still) a bit limited. Not that anybody asked, but I would suggest starting by coming up with a really good well-documented design (like, explain the battery management (charging, balancing, regeneration, handling bigger/smaller/more packs...), explain the control algorithm, what size of motor it is able to power, etc...). That way anyone who comes along and says "I want an Arduino" or "I want a TI chip" or "I want an NXP chip" or whatever, can take that design and run with it. One of my pet peeves about most so-called "open source" designs is that they really are more build-to-print recipes of HW and SW to replicate one design, which - in addition to not helping anyone learn very much - becomes useless as soon as the microcontroller or power FET or some other key part is discontinued. Then people have to reverse-engineer the hardware or source code part-way to get back to a point where it can be subtly modified and then built up again. Not only is doing design work on paper, and documenting it as you learn, generally good engineering practice, it's also a lot cheaper than making a lot of mistakes in "real" hardware. For a really simple project built on others' building blocks (e.g. TI motor control peripheral), maybe it's less of a big deal, but then you build in a dependency on those building blocks, which causes a legacy/reuse issue. I know this is not really the "hobbyist way" of doing things, but speaking as someone who has contributed to, and attempted to re-use, various so-called "open source" designs over the years, it is really beneficial, and helps get everyone aligned.
  3. Haha, touche. Actually I did find a few interesting posts while thinking earlier today that maybe I shouldn't give up so easily and I should look for good cold weather gear since I could see bits of pavement. Sure enough, in the few hours since that thought, we got 4" of snow, on top of the existing patches of compacted snow and smooth ice.
  4. Hi guys... just resurrecting this thread as I got distracted and never fully fixed this issue. If anyone has some spare control boards - working or not - or I/O boards (with the "spring" antennas and photoresistor), and/or schematics, I would appreciate it! Or else maybe this will be the one I use as a donor for my "new control board to fix all the stupid things China does with control boards" project, haha. But you know the old saying, change only one variable at a time. So would like to get it working confidently before I start mucking around. Thanks for any leads!!
  5. Speaking of this, if you think drivers are rude around cyclists or EUCs, I can tell you that it is far worse for horse/carriage users. I'm sure some people will laugh at this comparison, but every group has their reasons for liking the transportation method they choose. Misguided people exist in all walks of life. This same thing happened with drones, whose sudden proliferation, irresponsible use, and "scary" possible future use cases caused the regulation of all R/C aircraft over a particular weight. I think it's a bit exaggerated to say the US "often" runs counter to public safety. Not to mention, there's a broad range of attitudes about what makes the public "safe." I guess the brave new world of lightweight personal EVs will make sense in certain areas, but around the Plains and Great Lakes, there is simply not a viable personal EV solution that will go through a foot of snow and ice, and keep the occupant comfortable in subzero (-20c) weather, day or night. I personally use the next-best option and use an electric car... but then get flak from people who gripe about the carbon footprint of the cost of engineering and manufacturing electric cars and batteries. Every bit of information I have seen lately suggests that people are looking for more walkability and bikeability in their cities. How many people will walk when it's below 0 is a matter of some debate. So far, EUCs and e-bikes are fully permitted by my state, within motor output limits. This seems reasonable to me. Who knows if some new federal legislation will change this, but I expect not, unless the EU talks them into it.
  6. The fact that juvenile items should be beginner-friendly does not mean everything beginner-friendly is juvenile. A better analogy would be comparing a 2-wheeled motorcycle to the 3-wheeled Can-Am Spyder. The fact the latter is wider and inherently more stable doesn't make it juvenile, it's just a different take on a related product. Some people like one, some like the other. There are tradeoffs to each. If you guys have Segway minis gathering dust in a closet because you hate them so much, I'm open to donations so I can witness their terribleness firsthand! My earlier comparison was (I think?) to the original Segway units that had the handlebars. That doesn't mean accidents can't happen, but it seems like it would inspire more confidence to have a giant lever you're holding onto at all times, since you can more easily overcome the torque from road imperfections, etc.
  7. Yes, I hope I'm clear that I am with you on these points 100%... the video made a reference to "people would not buy EUCs because some are made by Ninebot, which is somehow related to Segway, and everyone hates Segways because they are nerdy." (Paraphrasing ) Even used, most seem to continue to be a couple thousand bucks. Yet, the cost and nerd factor doesn't stop people from having "Segway tours", whereas I think mass market EUC tours are still a long way off.
  8. I liked the video, too, though I'm not sure I ever got much out of how the Z10 is. I agree the original Segway was a little "nerdy" but I'm very doubtful it singlehandedly derailed personal transportation for 17 years. And for 100% sure, nobody is avoiding EUCs because a fraction of the units in operation somewhere on the planet say "Ninebot" if you squint real hard. I doubt most people even know Ninebot as a brand has anything to do with Segway. It's hard to judge how the market will perceive something. Those sit-down EUCs are another example... they could be really positive (you're riding half a motorcycle, how magical!) or really negative (you're riding half a motorcycle, where's the other half, tryhard, back at the mothership!?). More likely, it will be a blend of both, depending who is observing. For better or worse, two-wheeled vehicles are inherently less dangerous, and you can't "transform society" with a product that occasionally randomly causes moderate injury to its users. Indeed, I'm a younger-middle-aged, fully able-bodied person, well accustomed to balancing tasks, and I can still feel where my S2 caught me in the ankle when I was learning to ride a couple years ago. Incidentally I never had a severe injury learning to ride a bike, because: 1) it did not actively speed itself up to run over me, and 2) you can put your feet out and still move while you're on a bike. The analogy with bike riding is not quite right, in my opinion... to me it's more like learning to ride, well, a unicycle. One where you must never move your feet. I made a couple posts early last year (one in Safety, one in General Discussion) regarding my ongoing thoughts about making EUCs safer, and a minority voiced any interest in safety... indeed, a couple even said something to the effect that "it's no fun if you take the risk away". I'm not saying that mentality is good or bad, but as long as it persists, EUCs will likely not appeal to a mass market, or if they ever do, it will only be until a major lawsuit causes a flurry of bad press. Of course the promise of life-changing alternative transportation has been around forever. Governments can't do very well integrating ESTABLISHED modes of transit (pedestrians, bicyclists, and vehicular traffic), despite decades of effort, so I'm not holding my breath. And of course there's the weather issue. The comparison to the iPhone and Steve Jobs is a bit of a stretch, but I already made this response too long. :)
  9. pst

    Motor Recommendations for 3D printed build

    Well, since you ask... The biggest reason is that "cheap used machines" are not always easy to find. Local craigslist and the classifieds here do not seem to have many cheap wheels come through. Though, "cheap" is relative. I'm a few days late for the IPS Zero I guess. Another factor is that used equipment may have small (or large) problems with it, and by definition will be operating with older technology (not that a ton has changed). And it would be nice to know the specs of the motor being used. Ideally I would like something I can build more than one of. Also I'm not keen on buying perfectly functional products and ripping them apart, when other people might be happy to own them and use them as intended. But sure, if someone has a cheap wheel they'd like to provide to the cause, maybe something that worked fine until the control board / FETs let go, please let me know! Or I could post something to this effect in the classifieds area.
  10. pst

    Motor Recommendations for 3D printed build

    I didn't see any response here but also curious about a similar subject (though would prefer a slightly larger motor). Any preferred vendors, or even some specific links to decent suppliers?
  11. "Fault tolerant" covers a wide range of options, including simply using existing sensors in a smarter way. Adding a strip of metal to sense current draw (or using the one that probably already exists) isn't exactly "sophisticated engineering." As long as people keep buying the products, indeed, the only reasons would be things like market perception, reducing exposure to liability, or the satisfaction of addressing a common source of injuries experienced by their consumers, though I realize that's idealistic of me to expect.
  12. "Slow itself"... "limit itself in speed"... whatever semantics you prefer. Current-triggered tiltback rather than speed-triggered tiltback, essentially. @meepmeepmayer got the gist of what I was trying to say... essentially "do all the stuff that's currently done, just do it sooner, a little smarter, and build in overhead rather than allowing the system to overstress itself and fail abruptly without adequate warning, resulting in (preventable) injuries. Right, and if the market will bear $1000 for something designed with "screw together and see what works" engineering, then I'm not here to change anyone's mind. It's just very different from what I'm used to, so I'm curious to probe people.
  13. Maybe a more apt example would be pedal unicycles whose pedals occasionally fall off when you pedal too hard. Even if it's a niche, I'm not sure it means basic safety measures and due diligence shouldn't be in place. I don't mean to make more out of it than it is... you guys each have more experience in your little finger than I have in my lifetime, so if it doesn't bother you it shouldn't bother me. I just ask that you consider my perspective... during the day I listen to concerns about what happens when some component's pins may short together in 10 years because the solder was exposed to too much corrosive air in China, then I come home to read discussions about "let's compare the moderate injuries we got from failures that could've been prevented with a couple-cent shunt/resistor and slightly improved firmware."
  14. At the risk of getting back on the soapbox from my "safety" thread from several weeks ago, it seems to me that "cutting out like that" ought to be completely unacceptable, no matter the circumstances. Engineers know how to monitor current draw, voltage sag, battery parameters, motor heat, etc. Okay, a fuse blew, it's good that it didn't blow components or catch fire. Fair enough, but fuses exist to protect the system when a FAULT occurs. Riding up a hill is not a fault! The system should be designed to handle this gracefully... either slow itself to a sustainable cruising speed, or failing that at least alert the user of an over-current condition and come to a safe halt to allow things to cool down. I realize electric unicycles, personal electric vehicles, even vehicles in general, require the user to accept some risk, but it's not like this is some extreme sport for most people, it's just a personal vehicle. Can you imagine the outcry if some genre of electric bicycles or electric cars randomly failed, flinging their occupants at the ground, just because there was a hill, or maybe a busy intersection where you needed to accelerate? And the best answer to them is "well, at least it just blew a fuse!" Even if today's EUC riders don't see any problem with this, I can almost guarantee that as these vehicles trend toward more mainstream popularity, such cases will result in draconian, fun-killing, top-down regulation, and/or strict legal prohibitions in the name of safety, and I would hate to see either of these things happen, so I hope the manufacturers voluntarily get their act together before it comes to that. Anyway, rant mode off. Would be interested to hear if I'm alone in this thought, though. The response to the other thread was inconclusive to say the least.
  15. So, sorta-good news... I found the issue with the 14C... got the control board out and noticed that the giant resistor on there was fried. Also the capacitor is a bit damaged, not sure if it's related. Replacing with a new control board and having the "button board" unpopulated results in the headlight lighting on one side, no taillight, the motor works fine as long as I hold the power button down, then immediately turns off. Populating the board results in no light, no functionality. It seems the lead to the photoresistor got crunched so I will apparently have to fix that, but would such a problem cause this behavior? Does anyone know whether there is a source for schematics of the control board? I guess since I have another one I can try reading the stripes off the resistor but would like to know the exact specs (wattage, etc.) of this resistor to attempt to repair the old control board. Also, does anyone know how the switches work on that thing? Is it proximity? Or what? Seems to be a real trick to get the side panel screwed on correctly.
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