The schools Assistant Director has a similar globe, major exception..his is covered in dents from when the power goes off and the globe hits the floor. Kinda sad looking, but it still works.

Dont know why but that made me really laugh!! .
For a piece of art that might or might not be a problem!

 

Ok lg... it will take a while until I arrives but I will surely contact the forum on this thread... thanks.. and how much do u think I could get space between? I would like as much as possible ofkours. The object would be about 300 grams

 

300 grams! thats a fair bit! I will need to mess with coils for that kind of weight. maybe need a rethink, but I wont know until more wire arrives. distance will depend but you wont get much more than 2-3cm without getting complicated at that weight, I am only guessing but I would think a coil top and one bottom, of course then you have to worry they are in balance, or it will flip over!
also you want to avoid Oscillation as it gets unstable, the bigger the distance the more it oscillates, go on make me laugh, tell me how many feet distance you want

 

I have been thinking about this, distance will be important, the following is some thoughts but please remember I am not one of the clever people, I am a kid and beginner so I dont always get it right!
The hard part is not taking you down a path you cant do, we have to keep in mind that I have access to alot of equipment, so what looks more than possible to me may be alot harder for you. I can do alot of the grunt work, that isnt a problem but what might be is the following.
With a heavy weight and large distance, my instinct would be to go with a top and bottom coil or say 4 coils (in the corners) that sit at the top (pull) or the bottom (push), the trouble is If I was doing it myself I would reach for a micro to make it easy, otherwise you are looking at a more complicated design, for example if you went with a coil hidden in each corner you then have to have a mechanism that will respond to keep things level, or you start to turn over.
Now when you have an oscilloscope and that, its easy enough to hook it all up and tweak things to get it right, no two hand wound coils will be the same, the other option is to send the piece to me and have me fit the coils, but then you dont get to do it, and thats most the fun part! I would suggest you try and go with 2.5-3cm tops! at 300grams you will need a fair bit of power, sounds ok but start getting over 5A and you have all kinds of problems, not least the expense of a PSU that can handle that sort of current, it needs to be fairly well regulated as well, you dont want oscillations creeping in.
I would be tempted to make whatever it was Hollow,there are some clever tricks to hide the fact things are hollow, especially in wood. Also alot of current means you have to start worrying about heat.
Just a few things to think about, I am not trying to put you off, just give you an insight into why planning is going to be important, making stuff float is easy, making something specific float is harder! heavy objects and large distance is very hard(for me anyway)
LG

 

I have been thinking about this, distance will be important, the following is some thoughts but please remember I am not one of the clever people, I am a kid and beginner so I dont always get it right!
The hard part is not taking you down a path you cant do, we have to keep in mind that I have access to alot of equipment, so what looks more than possible to me may be alot harder for you. I can do alot of the grunt work, that isnt a problem but what might be is the following.
With a heavy weight and large distance, my instinct would be to go with a top and bottom coil or say 4 coils (in the corners) that sit at the top (pull) or the bottom (push), the trouble is If I was doing it myself I would reach for a micro to make it easy, otherwise you are looking at a more complicated design, for example if you went with a coil hidden in each corner you then have to have a mechanism that will respond to keep things level, or you start to turn over.
Now when you have an oscilloscope and that, its easy enough to hook it all up and tweak things to get it right, no two hand wound coils will be the same, the other option is to send the piece to me and have me fit the coils, but then you dont get to do it, and thats most the fun part! I would suggest you try and go with 2.5-3cm tops! at 300grams you will need a fair bit of power, sounds ok but start getting over 5A and you have all kinds of problems, not least the expense of a PSU that can handle that sort of current, it needs to be fairly well regulated as well, you dont want oscillations creeping in.
I would be tempted to make whatever it was Hollow,there are some clever tricks to hide the fact things are hollow, especially in wood. Also alot of current means you have to start worrying about heat.
Just a few things to think about, I am not trying to put you off, just give you an insight into why planning is going to be important, making stuff float is easy, making something specific float is harder! heavy objects and large distance is very hard(for me anyway)
LG

i want to spend as little as possible ofkors, but i could spend about 70 80 $ on it... you think that could be enough? and u must know im all noob about this and im waiting for you or someone else to star guiding me thru it... i cant do nothing without it... soon i will order disc and make it but about anything else i have no idea what to do, nor what are you talking about

 

I am still waiting for winding wire to show up, once I get that then I can give you some idea what is possible, do you have a old pc ATX power supply hanging about? the most expensive part would probably be the PSU, the electronics shouldnt cost very much, without power supply under £15.
If I was you I would try and get the weight down a bit, maybe get clever and make it hollow? any reduction would help, but more the better.
The last coil I had I have burnt out, I was pushing 6A and trying to lift 250g, very unstable. But I need to mess with it all alot more yet. There seems to be a point at which the weight goes from easy to very very hard, I will wind another coil when the wire arrives and find out where that point is, use that as your max weight.
I would like to keep the coil power under 3A, my aim is around 1.5-2A but I dont know if thats possible with anywhere near the weight we are talking about at the moment.

 

I am still waiting for winding wire to show up, once I get that then I can give you some idea what is possible, do you have a old pc ATX power supply hanging about? the most expensive part would probably be the PSU, the electronics shouldnt cost very much, without power supply under £15.
If I was you I would try and get the weight down a bit, maybe get clever and make it hollow? any reduction would help, but more the better.
The last coil I had I have burnt out, I was pushing 6A and trying to lift 250g, very unstable. But I need to mess with it all alot more yet. There seems to be a point at which the weight goes from easy to very very hard, I will wind another coil when the wire arrives and find out where that point is, use that as your max weight.
I would like to keep the coil power under 3A, my aim is around 1.5-2A but I dont know if thats possible with anywhere near the weight we are talking about at the moment.

i will buy it if needed... its not expensive. i bought two frisbee's and they are around 100 gram each, in the middle i thought about bending a wood sheet 1mm thick, it shouldnt be heavy... but if the weight is very important i will search ebay for better pieces maybe find some lighter frisbee... or think of something different but i dont know what will be better than frisbee, its light as is and its strong enough to handle the situation. carbon maybe...

 

Will someone recap?

I'm not following very well.

Does the levitated part need magnets?

I found some videos of hollow steel spheres.
http://www.youtube.com/watch?v=RCqjfieeGt0
Can I assume they are legit and no magnets in the spheres?

As a magnet or iron is needed for the levitated part, it seems a super thin delicate hollow steel structure is the lightest possibility.

If magnets are needed, then that will be the heaviest part.

 

i dont know what will be better than frisbee

I've already suggested styrofoam pizza trays. They're circular, with a rim (so similar shape and size to a frisbee), weigh only10.7gm each and can easily be painted.

 

I've already suggested styrofoam pizza trays. They're circular, with a rim (so similar shape and size to a frisbee), weigh only10.7gm each and can easily be painted.

As I don't understand how this works.

Would there be magnets attached?

Or could foam be painted with iron?

 

As I don't understand how this works.

Would there be magnets attached?

Or could foam be painted with iron?

ok back from school , you dont actually needs magnets to make things levitate, any ferrous metal will levitate. The reason you use magnets it so you dont have to use a huge coil (one reason anyway), magnets or metal plates can be glued in place or hidden under veneer etc.
In this case because of the weight magnets would work better, I think the main problem with polystyrene is the look! But thats not my department on this , Frisbee's will work ok, they might need sanding down a bit to shed a little weight.
Untill I can get more wire delivered I cant get any figures together, the main reason I want to keep the weight down is to keep the amount of current needed in the coil down, otherwise we have heating problems and the whole expense of a PSU that can deliver the current, bigger mosfets and heat sinks etc.
I have used a 1.8A coil with no problems, but much more than that and I think it will get harder to do, what I need to do is work on the coil and see how many turns etc work best for the weight we have. If I was a maths genius I could probably do alot of it on paper, but I am not, so I have to get the information from tinkering

 

So then, the magnetism of the magnets on the structure will more than make up for their added weight?

If net then is seems a foam structure with an iron coating would make sense.

 

So then, the magnetism of the magnets on the structure will more than make up for their added weight?

If net then is seems a foam structure with an iron coating would make sense.

The favored magnets are the tiny neodymium type, very small very strong. you can get them the size of a coin cell, but they have a great deal of pull on them. for my own project I dont need that kind of power, so I am using very thing magnets that they use on the back of fridge magnets.

 

i dont think styrofoam pizza tray would be good because its not hard enough for the forces that i will be using (i assume) and they look cheap and not professional...i mean maybe i could use it somehow but it seems too weak for the job...

 

you see here the guy is using magnets only, it seems, that was what i had in mind

https://www.youtube.com/watch?v=RCqjfieeGt0

 

That's the one I referenced in post 28. Prompting question about magnets being needed on the levitated part.

Seems that would save weight if an extremely thin sphere could be built.
Or a foam object covered with iron paint.

 

That's the one I referenced in post 28. Prompting question about magnets being needed on the levitated part.

Seems that would save weight if an extremely thin sphere could be built.
Or a foam object covered with iron paint.

little ghostman any news? you are still waiting for the wire, yeah?

i mean, the thickness and the aesthetics of the disk are important, im doing sculpture, not the act of levitation, i just need the levitation magic

 

still working on it, I am still not sure exactly what you want, the one in the video is push/pull, thats more complex from the point of view you will need H bridge etc, and to be honest if you dont have something like an oscilloscope etc, then your going to find it hard. a basic suspend a magnet/metal object, is not that hard. It dosnt have to be a magnet just ferrous material, the advantage with magnets is you need less power.
If your wanting something like in the video, I dont think you will find that easy. I would go down the micro route for that. the single electromagnet suspend thing, I would use a opamp. I have some wire now, So am I to assume you need to buy everything including a power supply? The reason I ask is, if you go the heavy route your costs will mount very quickly, same with wanting multi position control.
What kind of test gear do you have?