Engaging and Disengaging Magnetism

Discussion in 'The Projects Forum' started by Sjuan, Jan 12, 2012.

  1. Sjuan

    Thread Starter New Member

    Jan 9, 2012
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    Hi,

    I need a little help trying to determine the possibility of magnetizing and demagnetizing an object. My question is as follows:

    Is it possible to line two different slabs of thick glass with magnetic strips that can be magnetized to one another for the purpose of holding them together where they do not separate without great opposing force but that can also be demagnetized for the purpose of pulling the two slabs apart?

    If there is a way to demagnetize these slabs to allow them to be separated, by what process is this achieved? Is it a reaction that could be activated and deactivated by a button?

    I am curious as to whether it is indeed possible for them to be disengaged by using a button and whether electromagnets are strong enough to hold two thick panels of glass together without them separating or repositioning.

    Would they separate if the panels were to be dropped or would they stay in place? I ask because I have a very unique design concept for a device which would incorporate two different glass panels. I must add a microchip layer between the glass panels so as to incorporate a chargeable battery and an SD card. However, in using two glass panels as the back and front of the device, accessing the battery and SD card between these two panels must be as easy as accessing a battery or SD card on most smartphones today. This is why I am curious as to whether electromagnets would be strong enough to hold these two panels together without them coming apart or repositioning. This is also why I am curious as to whether dropping it would separate the pieces or whether they can be electronically demagnetized by button to provide easy access.

    I would truly appreciate any insight and thank you for your time!:p
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    yes its possible.. the devil is in the details though.. electromagnets can be tailored to provide as much magnetic force as you need. (ie think if a scrap yard electromagnet that can pick up thousands of pounds of steel)

    It is also possible to choose a magnet with a force that is suitable to hold something together and also allow it to be separated by hand.
     
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  3. Sjuan

    Thread Starter New Member

    Jan 9, 2012
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    Is it very expensive to manufacture small products which incorporate the use of electromagnetic coils?
     
  4. Sjuan

    Thread Starter New Member

    Jan 9, 2012
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    also, If one were to drop this device while it is being actively magnetized with electromagnetism, would it remain in place or would the force from dropping it separate the two panels? I noticed that you stated that it is possible to choose a magnet with a force that is suitable to hold something together and also allow it to be separated by hand but is it possible for it to be magnetized and demagnetized electronically via a button?
     
  5. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    If you are talking about a battery powered electromagnet, you won't be able to make one strong enough for any length of time until the battery is depleted, electromagnets are just a tad more resistive than a short circuit.

    Permanent neo magnets would hold something together strong enough to not move (assuming phone size), but weak enough that it could be pulled apart by strong fingers.
     
  6. Sjuan

    Thread Starter New Member

    Jan 9, 2012
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    So basically what you're saying is that there is no real electronic way to demagnetize a magnet strong enough to hold two glass panels together? The only option is to pull the pieces apart? Would they come apart if dropped?
     
  7. wayneh

    Expert

    Sep 9, 2010
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    The only way to turn a magnet "off" is if it is NOT a permanent magnet, ie. it needs to be an electromagnet if you want to turn it off. But the HUGE negative of an electromagnet is that its strength is directly proportional to the current running through it. I think that rules out the electromagnet idea for your device.

    One thing you might consider is a mechanical solution that allows you to use a permanent magnet. They can be dangerously strong (two 1" disks can give you a nasty pinch when they suddenly jump/snap together), but there are ways to slide them apart or pry them apart. Once you make a little progress, it gets much easier to make more progress.
     
  8. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    This seems to be a mobile device is that right? No mains voltage available?

    If you want to consider electromagnets you would need to provide the following information:

    Weight of the parts to be held together, applied pulling force, what would be the force on the magnets pulling them apart when dropping and how long is the battery supposed to energize the magnets.

    Unless it is for a short time, a battery powered solution is almost ruled out.
    Electromagnets ARE being used to lock doors etc. However mains voltage is available in these cases. http://www.sdcsecurity.com/class.aspx?id=1

    Otherwise, a mechanical solution with permanent magnets seems to be better suited.
     
  9. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    What is trying to be said is that yes you can build an electromagnet to be as strong as you want.. However since your device is battery powered there is a very good chance that the power needed by the magnet will drain your battery in a very..very short time.
    If this was a device with an unlimited power source (like plugging it into the wall) then yes it shouldn't be a problem to get what you are wanting.
     
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