

Show HN: Sketch, connect and simulate gears and chains - frankl
https://github.com/frankleenaars/gearsketch

======
lifeformed
I've always wondered - Consider the following gear arrangement:
[http://snag.gy/Tvsgi.jpg](http://snag.gy/Tvsgi.jpg)

The tiniest push on the gear on the left causes the gear on the right to fly
at thousands of RPM. Of course, there would be a ton of friction in the system
to overcome. However, what if the left gear was a pinion connected to a rack
that was pushed by an extremely powerful, yet slow-moving source, such as a
glacier or tectonic plate? With enough gears in this arrangement, an
unstoppable force moving just 1mm/year could spin tons of turbines.

Would this work?

~~~
ISL
Think about how large the forces will be at the first tooth interface at the
left (or in the rack). How strong does that tooth need to be?

Alternatively, you can use it the other way. Connect the gear at left to a
tectonic plate. Rest your finger on the gear at right. Voila! You can exert a
force great enough to stop the tectonic plate's motion. Plausible?

When Archimedes said, "Give me a lever long enough, and a place to stand, and
I'll move the Earth.", he actually meant something more like, "Give me a lever
long enough, and a place to stand, and I'll change the momentum of the Earth
very very very slowly. Unless that lever is incredibly strong and I have
access to a considerable source of energy."

~~~
ultimoo
"Alternatively, you can use it the other way. Connect the gear at left to a
tectonic plate. Rest your finger on the gear at right. Voila! You can exert a
force great enough to stop the tectonic plate's motion. Plausible?"

Nope, the question here would be whether the material used to construct the
left gear withstand the force that a tectonic plate exerts given that the gear
system will not allow it to move. I don't think the mechanics of the tectonic
plate exerting force on our gear system and our gear system exerting force on
the tectonic plate are symmetrical.

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Sunlis
Great for touchscreen, but tricky with a mouse. I would like to see an option
for drawing gears where mouse down sets the center of a new gear and dragging
away determines the radius.

~~~
gknoy
Absolutely what I was about to post. For a mouse user, mimicing the circle
construction mechanics (with preview!) used in the geometry construction
puzzle app that was linked a few weeks back [1] would be the bee's knees.

1: [http://www.sciencevsmagic.net/geo/](http://www.sciencevsmagic.net/geo/)

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basicallydan
This is really cool!

The ability to save a configuration and share it would be pretty cool, but as
well as that, other objects such as sticks which are attached to gears would
be a lot of fun. But then I suppose you have to involve gravity :)

~~~
tantalor
Rods and cams would be the next logical step.

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canthonytucci
This is cool but I'm learning quite quickly that I'm no good at drawing
circles with my mouse, perhaps a bit more forgivness when using the gear
drawing tool might make life a bit easier?

Overall I'm impressed.

~~~
gcb0
Will probably send a pull request just to be able to draw gears by the
diameter or radius instead of the perimeter.

can't even draw a square with the clitmouse...

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brbcoding
I have no real use for this, but that didn't stop me from playing with it for
30 minutes!

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caseorganic
Love this! It's very intuitive and fun to draw gears of different sizes and
hook them together.

I'd love to be able to make more complex gears. I immediately tried to make a
compound gear set with three gears and two different bands.

That got me thinking about "Incredible-Machine" puzzle features and how fun it
would be to actually try to build working things like clocks, bikes and
machines with this.

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nicpottier
Really enjoy the different take on the interface.. feel like you might be
missing something in having modality though, seems like you could combine the
actions for drawing a gear and drawing a belt, which would make it a bit
neater.

Any plans to add more complicated gear types? Would love to see something like
this enabling easy explanations of watches and the like..

~~~
Sukotto
In case you're interested, here are two of the best video's I've seen
describing how a watch works (
[http://www.youtube.com/watch?v=OiCPu0SjEW4](http://www.youtube.com/watch?v=OiCPu0SjEW4)
) and how a differential works (
[http://www.youtube.com/watch?v=K4JhruinbWc&t=1m50s](http://www.youtube.com/watch?v=K4JhruinbWc&t=1m50s)
)

Don't let their _old_ school-ness throw you off. They are both extremely well
done and demonstrate in clear and simple language from first principles to
finished object.

------
kylebrown
Cool! Something like this is the first thought I had when I saw the old book
"507 Mechanical Movements in Dynamics, Hydraulics, Hydrostatics, Pneumatics,
Steam Engines, Mill and Other Gearing" on HN a few months ago[1].

1\.
[https://news.ycombinator.com/item?id=5660770](https://news.ycombinator.com/item?id=5660770)

------
yyao
Very fun!

Ideas:

\- draw involute teeth forms

\- allow non circular gears

\- add other linkages

\- plot force (torque) and velocity (rotational velocity) against time or
position

That would be a pretty slick tool for some quick back of the envelope type
calculations.

------
EzGraphs
Reminds me of Mindstorms:

[http://www.amazon.com/Mindstorms-Children-Computers-
Powerful...](http://www.amazon.com/Mindstorms-Children-Computers-Powerful-
Ideas/dp/0465046746?tag=duckduckgo-d-20)

In the intro of the book Seymour A. Papert describes how gears provided an
early concrete framework that made understanding abstract mathematical
concepts presented at a later point much easier to visualize and apply.

------
milesokeefe
Very good experience on the latest iPad. I wish there was a way to delete
gears though.

Also having the play button toggle pause/play would be nice.

~~~
Sunlis
Drawing a slash through a gear seems to delete it. I'm not sure whether or not
that is intentional

------
jawerty
This is really cool. I could definitely use something like this when testing
gear functionality on a bot I'm making.

------
bockris
I don't have my tablet with me but I'm eager to try it. Have you tested on
Android?

~~~
frankl
I tested it on my 2010 android phone and it just barely works on that. More
recent android tablets should be able to run it quite smoothly.

~~~
bockris
I've played a bit on my desktop browser and it's fun! Can't wait to show it to
my kids. I've looked for similar things a long time ago and only found Java
apps/applets. I like that this is browser based.

Do you have a TODO features list? I don't know Coffeescript but this would be
a good learning experience for me. I can think of at least one feature I would
like to add.

~~~
frankl
Currently there's no todo list with features like other types of gears, more
easily creating gears of specific sizes and the like, but I would very much
welcome contributions of that type. I ported this version from the original in
java, to make it usable on mobile devices, because they are much more widely
available than e.g. wacom tablets.

I'm using the GearSketch environment in my PhD research to study different
forms of support for learning about gears. For instance, I created a puzzle
generator that creates concrete gear configurations based on abstract
descriptions (e.g. there are two unmovable gears, one larger than the other;
goal: connect them in such a way that the large gear will turn faster than the
small gear). Using each student's solutions to earlier puzzles, the software
tried to model their individual understanding of the gears domain and create
new puzzles based on that. Turns out accurately modeling student knowledge is
hard. ;)

The students using GearSketch are 10-11 years old, and understanding the
interactions between the normal gears and chains is already quite challenging
for this group, so my current focus is not on adding more elements. But like I
said: I'd love to see others working on it and would be available to help.

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neckro23
This is pretty neat. I've been doing a similar thing lately (rendering
arbitrary-sized bicycle chainrings in SVG), so I have gears on the brain.

I'm surprised this one uses canvas instead of SVG, actually. Compatibility
reasons?

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tantalor
Please add a permalink feature.

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jack-r-abbit
very nice. very smart how it won't let you put gears together that will
violate their rotation. would be wicked if you could right click (or otherwise
select) a gear and edit its radius and/or tooth count.

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acomjean
reminds me of Arthur Ganson, artist who sometimes makes homemade gears. Has
fun with gear ratios too (I think the machine with concrete will spin 1
revolution in 10000yrs if I remember correctly).

[http://www.arthurganson.com/pages/Sculptures.html](http://www.arthurganson.com/pages/Sculptures.html)

I was a museum gaurd at an art museum that had his work last century. He now
has a permanent home at the MIT Museum.

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jmanamj
At last, I have found the true purpose of my GNote II. Things get a lot more
complex when you realize you can drag gears around with chains attatched after
you place them...

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instakill
Impossible to add the chains with a touchpad.

~~~
frankl
Using it with a touchpad is far from ideal, but you should be able to manage
it by drawing the chain very widely around the gears. The chain will be
tightened automatically.

------
ne0phyte
_Uncaught TypeError: Type error - gearsketch_main.js:53_

Am I the only one getting this? Chrome 28; Windows 7.

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mdturnerphys
My (almost) 4-year-old has a new favorite activity. Thanks!

