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Gears

ciechanow.ski

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Re: Gears

#151

Post by TaylorAlexander »

StavrosK wrote: post #145
TaylorAlexander wrote: post #74

I really like this presentation! It’s wonderful. I don’t mean to hijack but I thought this would be an appropriate place to share a photo album of the 3D printed planetary gears in my open source robot: https://imgur.com/gallery/GqXD2Zj I’ve been 3D printing gears for some years now and I want to spread the word that 3D printed gears actually work really well! The gears in the image album above have been operating on…

That project looks great! I'm very tempted to start building this because of how good it looks, but I know it would take lots of time and effort, even with the designs already available. As an aside, would something like https://www.makerfol.io/ be useful for your build log? I see many people using imgur for this but it's always struck me as suboptimal.

Thank you! It’s certainly an involved project. I recommend starting by building one motor and gearbox assembly and getting control working from python. If you can get that far you can build the rest!

And the website you linked looks nice. There is also hackster.io and hackaday.io. While those sites are fine, it becomes one more thing to update. I prefer imgur for simple photo albums as that integrates well with reddit, my primary promotional place. Imgur actually works really well for me there. And then my real build updates are on my YouTube channel. And I have my own website where I try to throw everything.

So I end up trying to funnel people to my website and just using whatever media hosting makes sense for that particular media.

Re: Gears

#152

Post by StavrosK »

TaylorAlexander wrote: post #151
StavrosK wrote: post #145

Earlier quoted context omitted.

That project looks great! I'm very tempted to start building this because of how good it looks, but I know it would take lots of time and effort, even with the designs already available. As an aside, would something like https://www.makerfol.io/ be useful for your build log? I see many people using imgur for this but it's always struck me as suboptimal.

Thank you! It’s certainly an involved project. I recommend starting by building one motor and gearbox assembly and getting control working from python. If you can get that far you can build the rest! And the website you linked looks nice. There is also hackster.io and hackaday.io. While those sites are fine, it becomes one more thing to update. I prefer imgur for simple photo albums as that integrates well with reddi…

That makes sense, thanks! Regarding the build, I didn't see any information regarding the control system on the material I saw, but I probably wouldn't want to make it as autonomous as you have. I'd probably connect an ESP8266 as the controller and a receiver for my RC radio and control it that way.

Out of curiosity, is there more detailed information about the controller somewhere?

Re: Gears

#153

Post by anderspitman »

pier25 wrote: post #104
anderspitman wrote: post #84

If someone ever makes the creation process for this type of visualization accessible to the average university professor, it could blow the lid of the digital textbook market. Most digital textbooks I've seen are basically just putting the text and images on a web page, and maybe integrating multiple choice quizzes. That's seriously under-utilizing the medium. They need to be interactive , and encourage the student t…

I developed some widgets for interactive books in primary and secondary education. We had different quiz widgets (multiple choice, etc) but also drag and drop stuff and other types of widgets. The people in editorial producing the books configured the widgets using custom HTML tags. It worked very well. As long as they knew HTML they could configure these widgets. The problem is that anything that is easy to produce…

I suspect the optimum balance would still be somewhat technical. Maybe something on the level of a spreadsheet. It takes some specific knowledge to use effectively, but is still fundamentally a simple and intuitive tool.

Re: Gears

#154

Post by chubot »

kragen wrote: post #43
chubot wrote: post #9

Earlier quoted context omitted.

It is indeed great, and probably one reason you don't see it more is that it's a ton of work! That's 5K lines of hand-written code! (view source and it's at the end of the page) $ wc -l gears.js base.js 4135 gears.js 904 base.js 5039 total I've wanted to make visualizations like this for my blog. Writing a blog post takes me around 10 hours, which is a fair amount of effort. I believe that the visualizations will tak…

Writing a small program takes much less effort per line than writing a large program, especially if it doesn't have to be maintainable and extensible, especially by other people. http://canonical.org/~kragen/sw/dev3/circlegrid.html only took me three hours of JS hacking, and it's like 200 lines of code. The simplified version of the basic COCOMO model in David A. Wheeler's "SLOCCount" is Person-Months = 2.4 * (KSLOC…

That's true, and like everything I'm sure writing JS visualizations gets faster with practice, and you become more familiar with the tools.

Still, after finishing the article, I'm impressed by not just the the number visualizations, but by their legibility and smoothness. I can't in any universe imagine it taking less than a week of full-time work. If you told me it took a month of full-time work I wouldn't be surprised at all.

----

I liked this concept of "interpretive labor" and that's what I'm really getting at:

https://distill.pub/2017/research-debt/

There’s a tradeoff between the energy put into explaining an idea, and the energy needed to understand it. On one extreme, the explainer can painstakingly craft a beautiful explanation, leading their audience to understanding without even realizing it could have been difficult. On the other extreme, the explainer can do the absolute minimum and abandon their audience to struggle.

I've been writing for public consumption for about 3 years and really feel that tradeoff. When I put effort into some writing or explanation, the result is better. People tell me it clicked, etc.

And I would say you can go a lot further than you think in bridging the gap. This article is evidence of that! Lots of people here are saying they wished they had this in high school, etc.

3Blue1Brown's videos are another example of that. I was fairly good at math in high school but if those videos existed then, I would have probably gotten a lot further.

----

This ties in nicely to your Dercuano notes which I have had open in my browser for awhile! There are many interesting topics there. But I also feel like you went to the other extreme and there's a lot of interpretive labor involved in reading them :)

Why did you decide to polish and publish the "memory models" post? I'd like to see more posts like that. (I could send you the notes that jumped out at me if interested.) Whenever I've taken the time to polish some writing, I've never regretted it. For some reason it feels annoying to start (probably because I have to clear my brain of other things), but when I'm doing it it's fun, and when I'm done, it's worthwhile.

Re: Gears

#155

Post by beachy »

roland35 wrote: post #112

A very cool style gear is a harmonic drive. It has a somewhat flexible inner gear driven by a cam which engages it to the outer gear. It allows for extreme gear ratios with high torque in very small packages (think helicopter pitch control). https://en.wikipedia.org/wiki/Harmonic_drive

Very cool! It looks like the output shaft has quite a bit of lateral movement, perhaps something like a Schmidt coupling (https://www.thingiverse.com/thing:233667) could be used to remove that movement and allow a fixed output shaft.

I last saw one of these inside an IBM 3890 check reader machine.

Re: Gears

#156

Post by linsomniac »

erikig wrote: post #134
alphaBetaGamma wrote: post #81

I have heard that it is good practice to always chose the number of teeth of two gears to be relatively prime. This is because there can be impurities in the metal, and if you have a small part of a tooth that is harder than the rest it will erode the opposing gear (there is always some friction going on). By choosing the number of teeth to be relatively prime, the wear and tear is distributed uniformly on the gears,…

Anyone that is fascinated by gears owes themselves a visit to This Old Tony's video on YouTube titled "Gears! - But Were Afraid To Ask" https://www.youtube.com/watch?v=Q-XOM4E4RZQ He goes into the nerdy depths of gear make-up, metallurgy, meshing, machining and mistakes as he manufactured metal gears on a mini-lathe.

I second TOT, his videos are just fun to watch. Plus, you learn something.

Re: Gears

#158

Post by catblast »

frankus wrote: post #72

Maybe I’m misremembering but isn’t torque usually expressed as a cross product of force and radius? (Making pound-feet the pedantic but correct phrasing of the colloquial “foot-pounds”) That way the torque vector points in the direction that a screw would move if you turned it in the direction it’s being forced.

That is the correct way to express torque with vectors.

The definitions in the blog post are not vectors, they are scalars and the dot is not a dot product, just multiplication. (F_t there is what is commonly notated as F_perpendicular). I agree it is confusing to those of us used to seeing bold letters usually used for vectors (and I would argue that using more conventional notation at even a basic level is better), but it's not wrong.

Re: Gears

#159

Post by SummerlyMars »

mtreis86 wrote: post #135

Slightly off topic but it has long bothered me that racing simulations let you pick arbitrary gear ratios in the tranissions and differentials. Real life has two restrictions, you can't have half teeth, and you can't have huge teeth count. A 3.00 ratio sure, 12:36 but a 3.01? No car differential can fit a 100:301 ratio gearset and 10:30.1 just won't turn past the broken tooth.

I'm not a car guy, and I don't know about the differentials, but don't continuously variable transmissions allow for this? I'm guessing they're not in common use on race cars, but in principle, shouldn't they allow for a 3.01 ratio?
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