Overbalanced Wheel (Fake Perpetual Motion Machine for Fun)

Of course, perpetual motion does not exist. But lots of great inventors, including Leonardo da Vinci, played around with the idea so I feel like I'm in good company. I think anyone who is interested in engineering, mechanics, and physics or the history of these fields will enjoy building this project.

I've always been facinated by the "Overbalanced Wheel", which is basically a wheel with weights that slide or move from a position close to the center of the wheel to a postion near the edge of the wheel as it turns; basiclaly shifting more weight to one side of the wheel to keep it turning in that direction.

I decided to build my "Overbalanced Wheel" out of an old CD (always great for DIY projects), some screws and metal brackets I bought at Lowe's and a few "secret" components that will be revealed in Step 5.

NOTE: Don't look ahead to Step 5 unless you want to take the fun out of perpetual motion!

First, check out the video!

Step 1: Materials & Tools (Non-Secret)

Non-Secret Materials Needed:

1 - CD
8 - 6-32 Cap Nuts
8 - 6-32 Screws
8 - 6-32 Washers
8 - 6-32 Nuts
6 - 1/2" x 4.5" x .035" Metal Mending Plate (Lowes 364404)
4 - 1/2" x 1-1/2" x 1-1/2" Metal 90D Plate (Lowes 364311)
1 - 1/2" x 3" x .035" Metal Mending Plate (Lowes 364323)
1 - 2" Metal Gear Shaft
1 - 1" Diameter plastic gear (to fit shaft above)
2 - Rubber grommets (same diameter as gear shaft)

Non-Secret Tools Needed:

Drill
Cutting Tool
Dremel
Screwdriver
Pliers
Hot Glue Gun

Comments

[Flying_MashedPotatoes]

Do really need more fake perpetual motion machines to perpetuate the world's stupidity?

[mikesoniat]

I had no intention of perpetuating stupidity. I said right up front that it was "for fun". I also thought it was an interesting project and many people here seem to agree.

[bakunin]

I am one of the agreeers! I think the process of building a perpetual motion machine, and then seeing it not work, is an excellent way to learn about the conservation laws of physics.

[billjoh]

I like this even tho its doesn't work. But what seems strange to me is every one thinks there is no perpetual motion machine when if you look down at your feet your standing on one. The earth.....?

[Treknology]

According to historical records, Earth days and years were shorter than they are today. Either our clocks are suffering a temporal anomaly or the Earth is really slowing down.

[Dilong_paradoxus]

The earth is slowing down because of tidal locking with the moon (there's a what-if.xkcd about this), not necessarily from friction. Space is very close to a perfect vacuum, so the friction effects are negligible.

[Treknology]

I didn't mention friction in this case, just that the Earth's rotation and revolution are slowing down. If you want to argue about Luna and tidal forces, do a basic Google check on tides in different areas, and you will find that the data does not match with Luna/tide theory. Some bodies of water exhibit FOUR tides a day instead of the "traditional" two.

[Dilong_paradoxus]

Sorry, I said that badly in my first comment. I didn't mean to contradict you, just to add clarifying information in the last sentence. Anyway, tidal locking doesn't have to mean actual tides in water. The moon is tidally locked with earth, so the same side always faces us, and the moon probably hasn't ever had significant amounts of water. Also, that's pretty cool about the four tides a day, although I suspect that's more due to harmonics in the water basin and delay between the passing of the moon and the actual high tide.

[Treknology]

When it comes to tidal harmonics, you have hit the nail on the head. Most of the moons in our system are "locked" so that only one side faces the host planet. However, Luna is the only one that has such a slow orbit that it never goes "retro-grade" in relation to the Sun.

[Beekeeper]

I have often wondered whether one could make a 'perpetual motion' machine using magnets to push a wheel around, instead of weights rolling or sliding towards the centre. I imagine a different number of magnets on an outer wheel such that there is some push and then pull. The whole thing suspended on magnetic bearings. If it worked, would one be using the energy inputted to originally make the magnets and it would only last until the magnets gave out?
Perhaps some of you geniuses out there would try it or tell me it is impossible.

[dreadengineer]

Unfortunately it is impossible. Though magnets seem mysterious, the way to think of them is like a "hill" in energy. (Or rather like a valley next to a hill, if you're considering the north and south pole forces on another magnet.) In order to get energy by rolling something down the hill (i.e. getting repelled by the magnet), you have to first put in exactly the same amount of energy when you push it up the hill to begin with. No matter how you arrange hills and valleys, you can't make a closed circular path that has net downhill movement. (As a proof of that: it has to get back to the same initial height, so it's net up/down movement must be zero.)

[Beekeeper]

That sounds logical but..... I believe one can shield one side of a magnet so that it has less effect on one side than the other. To take your analogy, wouldn't that mean that the hills are higher than the valleys? You can get more push than pull?
David

[dreadengineer]

I think I understand what you're saying. Unfortunately it's not possible to shield a magnet such that it's easy to approach in one direction and hard to approach in another.

You can do things to make the "slope" short and steep or long and gentle, but it ends up being the same total amount of energy. It's not possible to build a "one-way magnet" that pushes one way but not the other way, just like you can't build a "one-way hill" that is shorter to climb on one side than the other.

There's no reason not to buy some neodymium-iron-boron magnets and experiment though; there's still plenty of cool stuff you can do with magnets.


If you're interested in getting some more physics theory, there's a good series of intro to physics videos on Udacity: http://www.udacity.com/overview/Course/ph100/CourseRev/1

I'm not sure if it covers magnets specifically but it does cover analyzing potential energy and related stuff, so it's a good background for experimentation.

[Beekeeper]

Unless we humans have ideas, even if they don't work, we would still be living in caves. Thanks for sharing your expertise: I'll try giving my little grey cells something else to work on.

I have heard that if you spin a spherical magnet held in a vacuum above a cylindrical magnet it would be perpetual. But that requires a perfect vacuum and anyway there is no means of utilizing the spinning.

David

[Benzyl]

The loud whizzing noise and coarse rotation rather give this away, less a fake perpetual motion machine than a simple Ferris Wheel model. Suspend some Lego people from it perhaps?

[Treknology]

Hmm. A "Ferris" wheel where the occupants' cages slide and thump their way from the center to the outside and back again could be a really scary ride. You could be onto something here.

[mikesoniat]

Thanks for your opinion, Benzyl. I' m honored that you took the time to comment on my Instructable. Too bad you don't have any projects of your own posted. I'm sure they would be far superior to anything I could cobble together...

[GS Gnaneshwar]

Hi Mike, Excellent! Your simple approach for making this small project instigated me to go for a bigger version of Electricity generation. Is it ever possible ? Kindly comment.
Gnaneshwar, Bangalore, India.

[mikesoniat]

Thanks, but I'm not sure how this relates to electricity generation.

[mr fat]

I absolutely love this project! I believe that it is a 15 out of 10 winner!

[mikesoniat]

Thank you!

[Treknology]

I love this, although the constant "click-clack" would get a little annoying.

[mikesoniat]

I guess I better get used to it; after all it is perpetual!

[Treknology]

At least it has an "Access Mode Ready" function that has replaced the "Standby" button which itself has replaced the appallingly stone-age "Off" switch!

[kevins82]

(removed by author or community request)

[mikesoniat]

Thanks, Kevin. The actual design was my own idea, but I was inspired by Bhaskara, Honnecourt, and da Vinci.

[Treknology]

The earliest design along these lines was a wheel with angled spokes, and rails in the spokes for weighted balls. When spun, the wheel would continue for quite some time but, like all these ideas, friction would ensure that it ground to a halt.

The two examples of "perpetual motion" that almost achieve their aims are:
1. High frequency induction waves circulating in an aluminium disc----unfortunately the very act of measuring their presence depletes them.
2. An rounded-corner triangular shaped piece of metal with a bike-chain sliding around its outside edge. Friction does not appear to cause as much of a problem, but the wear-factor on the triangular plate means that as it gradually alters shape, it becomes defective.

[wjcarpenter]

I like the whole idea of this. It's in the sweet spot between simple and complex.

I wonder if you (or anyone) has some bright ideas for a more "finished" way of cutting into the CD. I know if I do it more or less by hand the way you did it, I'll end up with a sloppy mess (and blood in the streets). I've got a dremel and various other simple tools, but no SDI space-based laser weaponry.

[mikesoniat]

Thanks, WJ. I have to admit, cutting the CD was a challenge with my basic tools and limited skills. I'm sure someone could do a much better job with the proper equipment and experience.

[Treknology]

If I dare try building a similar project, I will use Hard Drive platters and a milling machine.

[lemonie]

Build a base that incorporates an intermittent magnetic-pull, you'd need some kind of sync' with an electromagnetic-pick-up. If your bearings are really-smooth you could get a nice steady motion, and control speed by moving the electromagnet about.

L

[rimar2000]

Very nice!

[mikesoniat]

Thanks! I enjoyed making it.

[JayGeeBSE]

I like the idea but the use of a processor seems way over the top. Why not connect your power supply direct to the motor in the servo and omit all the electronics? Maybe a series resistor to limit the speed. You can probably hide a switch under the base, so it runs when you press on the frame - tell people you have to steady it or it shakes too much. If you must drive the servo with pulses you can buy a servo tester with a speed (position really) tweaking pot for a small sum. Cheaper, smaller and simpler than your microcontroller but you do still have the switching problem. A small rechargeable pack behind the CD would make it easier to disguise the power source.

[mikesoniat]

I actually tried a series resistor and a pot, but the results were unreliable. The biggest problem was getting enough torque to turn the wheel with the reduced voltage. I also tried using batteries, but the "Touch Sense" feature (which I really liked) didn't work well without the USB connection. Anyway, like I said in the text, I had the Teensy board because I backed them on Kickstarter. And I guess I was looking for an excuse to use it!

[giocad]

very educational.

[mikesoniat]

Plus it was fun to build! Thanks!

[Jimbok3]

technically it is possible in space......

[LaffyDuck187]

in space there is still friction

[Jimbok3]

not for free floating objects