Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Jeremy McCreary]

Why let Saturn have all the fun when you can make your own ring systems in living color?



"Ringmaker" is my term for a spinning top designed to sweep out concentric rings of color at speed. This adjustable "CYMK" ringmaker produces bright, high-contrast rings of many colors by "mixing" reflected cyan (C), yellow (Y), magenta (M) light against a black (K) background...



The perceived mixing is just an illusion cooked up entirely within the brain-eye system. Since video and even still capture interfere in various ways, you really need to see it in person to get the full effect.

As a top, this 66 g ringmaker stays up ~12 s by hand -- not bad considering the rotten aerodynamics. But for this video, I ran it in a motorized test rig at a steady 840 RPM — with surprisingly few centrifugal failures.

And for the Luddites who like their rings the old-fashioned way — in black and white...





See video description for details.

[Jeremy McCreary]

This blacklight version comes across better in video, but you still have to see it in person to get the full effect.



Differences from CYMK version:
• Brighter, higher-contrast rings from fluorescent panels emitting (not reflecting) orange (O), lime (L), and blue (B) light
• Smaller-radius chassis with less drag and free-standing wobble
• Increased test rig terminal speed (920 vs. 840 RPM)
• Longer free-standing spin times by hand (15 vs. 12 s)

See video description for details.

[ta0]

To spin your Venus rings top you made what looks like a Mars rover 

I guess with fluorescence it's easier to combine the colors on video.
One day I need to really investigate what are the best options for averaging frames on a video. I guess it would be easier to just average several photographs into one photograph that will show it like the eye sees it. Stacking photographs is routinely done in Astrophotography, for example, so there must be lots of help available.

This reminds me that I need to repair the Electric Top I got from Olney's collection (and I promised to Kirk I was going to repair). This photo is from an auction, I don't have the box or the instructions:



Unfortunately, it's not really a top but a motor designed to show color mixing.

[Jeremy McCreary]

To spin your Venus rings top you made what looks like a Mars rover 

Hey, thanks for the idea: An autonomous self-propelled space rover / top gantry with embedded LEGO EV3 data-logging robotics computer, motorized steerable wheels, and robotic arms for picking up and chucking downed tops. Probably doable.

Interestingly, this gantry and its brushed permanent-magnet DC motor provide a useful way to compare a top's total braking torque at terminal speed to that of a low-drag reference top. Stay tuned.

I guess with fluorescence it's easier to combine the colors on video.
One day I need to really investigate what are the best options for averaging frames on a video. I guess it would be easier to just average several photographs into one photograph that will show it like the eye sees it. Stacking photographs is routinely done in Astrophotography, for example, so there must be lots of help available.

This reminds me that I need to repair the Electric Top I got from Olney's collection (and I promised to Kirk I was going to repair). This photo is from an auction, I don't have the box or the instructions:

Unfortunately, it's not really a top but a motor designed to show color mixing.

Still, I'd love to see it in action.

Would also love your help in figuring out the (preferably phone) videography of such things. Previous attempts to shoot them with my fancy DSLR also met with limited success, but time to try again.

[ta0]

Still, I'd love to see it in action.

I'm working on it.
I found the patent form 1901:



I made new reeds working as brushes (g), but I discovered that the permanent magnets (C, C') are not much magnetized anymore.
I'm adding external magnets. I think I'm close.

[ta0]

When I got the Electric Top, it was missing one of the motor brushes (a brass reed). But when I disassembled it, the other also broke.
So I made new ones out of 1/32 brass foil (I couldn't find 1/64 brass what I think would have been better).
It originally had some ceramic insulators where the screws go through the walls that disintegrated when I took them off. I didn't replace them as the holes are big enough for the screws not to short circuit if centered.
I had to re-polarize the soft magnets made by the walls, which had demagnetized in 120 years time. Fortunately, I had some strong cylindrical neodymium magnets of both polarities with similar curvature. I left them overnight as you can see on the photograph:



This was the result. I think Kirk will be proud of me! 

[Jeremy McCreary]

I'm proud of you, too! This wonderful relic clearly fell into the right hands.

Especially liked the video persona of the last disk pair. Love all the crazy visuals you can concoct with these temporal partitive color-mixing effects.

Q1: I'm in the market for an affordable variable DC power supply. Do you like yours?

Q2: Is the power to the motor automatically cut somehow when you stall the shaft? Or perhaps more likely from that time, a centrifugal clutch or freewheel mechanism? Nice feature!

[ta0]

Q1: I'm in the market for an affordable variable DC power supply. Do you like yours?

Yes, I like that little triple DC power supply (variable 0-30 V at 2.5 A, +/-5V and +/-12V). The thing I like the most is that on the variable output you have separate controls (and displays) for the voltage and the current and it can work either as constant voltage source or a constant current source. But I bought it 20 years ago so I don't know what's the best option in the market.

Q2: Is the power to the motor automatically cut somehow when you stall the shaft? If so, nice feature!

Yes, and that is explicitly mentioned on the patent as a feature. The fixed magnets try to align the armature with them and in that position the circuit is open. So you can just leave the motor connected, start it like a finger top, stop it with your hand and just leave it, with no switch involved (when connected to a battery).

On the video I'm only applying 0.6V (and limiting the current to 1.2 A).  Once it was working I didn't want to risk it, so I was conservative. That's why it stops so easily when i touch it. But before realizing the magnets needed to be re-polarized, I put 2.5 A, so I'm sure it can more powerful and run faster. It's designed for batteries more than double the voltage I used. On the other hand, the "dry, salammoniac or bichronate" batteries mentioned on the instructions probably had high internal resistance, so they might not have given double the current.

[Jeremy McCreary]

I love this thread. Sal ammoniac (NH4Cl), as you know , is what makes salty licorice salty. And that's my very favorite kind.

NW Europe had a real soft spot for tops not so long ago. And that's exactly where salty licorice is most popular. Coincidence?

Best of all, ammonium chloride doesn't explode like its nitrate cousin.

[ta0]

I love this thread. Sal ammoniac (NH4Cl), as you know , is what makes salty licorice salty.

I didn't know that, but your comment made me look again at the first chapter of the "Electric Toy Making" book by Sloan. It describes in detail how to build yourself bichromate and sal ammioniac batteries. Hint: you need mercury but no warnings about safety anywhere.  In fact, the formula given in the appendix for amalgamating zinc looks like a nightmare safety suggestion for a young toy maker:

Dissolve one part of mercury in a mixture of two parts of nitric acid and hydrochloric acid  . . .

The electric top would have fitted perfectly with the subject of the book, which has a chapter on electric motors (but was copyrighted 10 years earlier).

One thing that I didn't mention is that the "top" will spin in one direction but not the other. If you want to be able to spin it in the reverse direction, you have to reverse the polarity of the battery.
I tried it with the same voltage but with 2.5 A limit and it does spin much faster.
I can see now that the name "top" is a little more understandable because it's started with a flick of the fingers like a finger top.