Naked Science Forum

Non Life Sciences => Technology => Topic started by: Seany on 24/05/2007 21:12:11

Title: Can a magnet near my phone, damage it?
Post by: Seany on 24/05/2007 21:12:11
If I hover a magnet over my slide phone, it goes wild. I know it isn't good for my phone, but I did it for fun. If the magnet goes close to it, the screen does the same as when the slide phone is up. If the magnet is far away again, it is just the same as the slide is slid down.

Why would it damage my phone, if it does damage it? And how?
Title: Can a magnet near my phone, damage it?
Post by: kdlynn on 24/05/2007 21:43:41
well i know that they can do horrible things to a computer. i'm not sure about your phone
Title: Can a magnet near my phone, damage it?
Post by: another_someone on 25/05/2007 00:28:51
A magnet can damage the disk (hard disk or floppy disk) in your computer because these are magnetically recorded.  It is unlikely there is very much that is magnetically susceptible in your computer (although a rapid change in magnetism can induce an electric current within the phone that might damage it - but by rapid change, I am talking about switching on a powerful electromagnet within a millisecond or so; I am not talking about moving a bar magnet closer or further away over the period of about half a second).
Title: Can a magnet near my phone, damage it?
Post by: that mad man on 25/05/2007 16:09:05
Although they do have some built in protection against weak local RF interference, a magnet would interfere a lot as its fairly strong in comparison.

The magnetic interference on the signal could cause some parts of the circuit to oscillate when they shouldn't causing a possible overload on some components and premature failure.

Bee

Title: Can a magnet near my phone, damage it?
Post by: another_someone on 25/05/2007 16:21:03
Although they do have some built in protection against weak local RF interference, a magnet would interfere a lot as its fairly strong in comparison.

The magnetic interference on the signal could cause some parts of the circuit to oscillate when they shouldn't causing a possible overload on some components and premature failure.

Bee

A magnet may be strong, but if it is a constant field (no wave function), then I cannot see how it will induce oscillation?

The absolute most that I could see a constant field doing is inducing a hall effect on some capacitive components, hence maybe slightly shifting their resonant frequency a bit.

I would agree with you totally if we are talking about an oscillating magnetic field, particularly if that oscillation is in the RF band.
Title: Can a magnet near my phone, damage it?
Post by: that mad man on 25/05/2007 18:01:28
A magnet will not induce oscillation itself but will have an affect on those parts that already are oscillating as Seany has already mentioned, his phone goes wild. Mind you, he didn't mention if this affected the sound or reception at all. [;)]

The magnet can cause an unwanted frequency shift in the oscillators coils and inductors that work in the RF band. If the shift was large enough and not calculated for it could cause a higher current drain in parts and damage to components. Mobile phones are very sensitive, operate at high frequency RF and if I remember right its the lower frequencies that require more power. So, suddenly changing from a high freq and low drain to a low freq and high drain could damage component that are not designed for it.

Bee


Title: Can a magnet near my phone, damage it?
Post by: another_someone on 25/05/2007 21:49:15
The magnet can cause an unwanted frequency shift in the oscillators coils and inductors that work in the RF band.

How so?

Are you suggesting that the core in the coils/inductors is reaching saturation?

Otherwise, I cannot see that a non-oscilating magnetic field will be able to induce a current, so how can it effect a coil.

Ofcourse, if the phone had a voice coil speaker, that might be influenced by an external magnetic field, but I would not expect that to cause long term harm.
Title: Can a magnet near my phone, damage it?
Post by: Seany on 26/05/2007 10:36:39
A magnet will not induce oscillation itself but will have an affect on those parts that already are oscillating as Seany has already mentioned, his phone goes wild. Mind you, he didn't mention if this affected the sound or reception at all. [;)]

The magnet can cause an unwanted frequency shift in the oscillators coils and inductors that work in the RF band. If the shift was large enough and not calculated for it could cause a higher current drain in parts and damage to components. Mobile phones are very sensitive, operate at high frequency RF and if I remember right its the lower frequencies that require more power. So, suddenly changing from a high freq and low drain to a low freq and high drain could damage component that are not designed for it.

Bee


Well, the sound part. If I manually slide my phone up, it makes a sound that it is turned on. If I manually slide my phone down, it makes a sound that it is slid down.

If I hover the magnet towards it, it makes the turning on sound, even though its not slid open. If I hover the magnet away from it, it makes the sliding down sound, even though it remains still.
Title: Can a magnet near my phone, damage it?
Post by: another_someone on 26/05/2007 13:07:08
Well, the sound part. If I manually slide my phone up, it makes a sound that it is turned on. If I manually slide my phone down, it makes a sound that it is slid down.

If I hover the magnet towards it, it makes the turning on sound, even though its not slid open. If I hover the magnet away from it, it makes the sliding down sound, even though it remains still.

Sounds to me like there might be some magnetic sensors used to detect where the cover is, and they are being fooled by the external magnetic field.
Title: Can a magnet near my phone, damage it?
Post by: Seany on 26/05/2007 13:16:32
Hmmm... Oh.. So when the phone slides up, a magnet attached to the slide mechanism is detected by magnetic sensors, which tells them whether it is slid up or down?
Title: Can a magnet near my phone, damage it?
Post by: another_someone on 26/05/2007 14:54:47
Hmmm... Oh.. So when the phone slides up, a magnet attached to the slide mechanism is detected by magnetic sensors, which tells them whether it is slid up or down?

I cannot say if this is so, but from what you describe, it seems a plausible explanation.
Title: Can a magnet near my phone, damage it?
Post by: Seany on 26/05/2007 15:13:26
Hmm.. Ok [;)] Thanks
Title: Can a magnet near my phone, damage it?
Post by: kdlynn on 28/05/2007 06:32:46
seany, i have to ask... you asked this question and then you got a new phone very shortly after... the magnet didn't break your other phone did it?
Title: Can a magnet near my phone, damage it?
Post by: Seany on 28/05/2007 12:19:49
Nope, it didn't. I used the magnet a couple of months ago, and never did it again, as my dad told me not to [;D]
Title: Can a magnet near my phone, damage it?
Post by: elegantlywasted on 28/05/2007 14:40:59
Seany- where I work I walk by magnets all the time and my phone does the same thing you are describing. 6 months and no damage. I am pretty sure that there is a magnetic sensor that is broken when the phone is opened, thereby causing the opening sound, but if you get another magnet that close to it the magnet sensor shifts and the phone thinks that it is being opened. I'm probably not right but its a thought.

Another point, dont forget that there is a magnet inside the speakers on the phone!
Title: Can a magnet near my phone, damage it?
Post by: Seany on 28/05/2007 16:59:20
Hmmm.. OK, thanks. Where do you work?
Title: Can a magnet near my phone, damage it?
Post by: benep on 28/05/2007 17:55:43
depends on how strong the magnet is but i put a magnet beside my phone and nothing happens but it was a weak magnet so my advice would be ---dont put a strong magnet next to it ;) ---
Title: Can a magnet near my phone, damage it?
Post by: Seany on 28/05/2007 17:59:43
Thanks for your advice. [:-\] Heehee
Title: Can a magnet near my phone, damage it?
Post by: elegantlywasted on 28/05/2007 18:30:11
Saeany I work at a video store (among other places) and our movies are locked in the cases by magents, so the case opener is essentially a big magnet, and whenever I walk by it I hear the bubble noise of my phone opening
Title: Can a magnet near my phone, damage it?
Post by: Seany on 28/05/2007 18:57:46
AHhh.. That is cool. [;)]
Title: Can a magnet near my phone, damage it?
Post by: paul.fr on 29/05/2007 20:48:14

Sounds to me like there might be some magnetic sensors used to detect where the cover is, and they are being fooled by the external magnetic field.

There is a sensor in the phone, but i am not sure if it is magnetic. I have some old phones and when time permits i will strip one to see. What you may find is that the magnet wipes you phones hard drive / memory and or data card.
Title: Can a magnet near my phone, damage it?
Post by: Seany on 29/05/2007 21:10:41
But it isn't a hard drive... Well.. It's a micro sd card which is in mine.. which is basically a flash card.. Would a magnet affect a flash card?

Oh, and thanks for stripping your phone. [;)] Well, in the near future!
Title: Can a magnet near my phone, damage it?
Post by: paul.fr on 29/05/2007 21:34:20
You have some form of computer inside you phone, that has a built in solid state or flash drive, plus your additional card. These can be wiped by a magnet.
Title: Can a magnet near my phone, damage it?
Post by: elegantlywasted on 30/05/2007 17:41:42
But isnt there a magnet in the speaker of the phone? Why doesnt that magnet wipe out the memory?
Title: Can a magnet near my phone, damage it?
Post by: Seany on 30/05/2007 17:42:53
Too weak a magnet?? Oh I don't know!! [:P]
Title: Can a magnet near my phone, damage it?
Post by: paul.fr on 30/05/2007 17:43:34
But isnt there a magnet in the speaker of the phone? Why doesnt that magnet wipe out the memory?

it is may too small to cause any damage.
Title: Can a magnet near my phone, damage it?
Post by: Seany on 30/05/2007 17:44:04
So how strong would it have to be?
Title: Can a magnet near my phone, damage it?
Post by: paul.fr on 30/05/2007 17:50:17
So how strong would it have to be?

do you have an old tape recorder? look how small the magnet is that deletes/records on to the tape, it is pretty small.

to wipe or corrupt a flash drive, i think a fridge magnet could do the job if place on to it. i will try and wipe some memory sticks with magnets when i get home.
Title: Can a magnet near my phone, damage it?
Post by: another_someone on 31/05/2007 02:55:44
So how strong would it have to be?

do you have an old tape recorder? look how small the magnet is that deletes/records on to the tape, it is pretty small.

to wipe or corrupt a flash drive, i think a fridge magnet could do the job if place on to it. i will try and wipe some memory sticks with magnets when i get home.

Do try - I will be interested in the result, since flash memory is supposed to be an electric charge device, unlike a tape recording, which is a magnetic recording device.

I would also add that the erase head on a tape recorder is not only extremely close to the recording media (actually in contact with it), but actually uses an oscillating magnetic field rather than constant magnetic field you would get on a permanent magnet (I am not saying that the tape would be impervious to a constant magnetic field, but is more susceptible to an oscillating field, so the deletion can be done more completely, and with a lower flux, than would be necessary with a permanent magnet).
Title: Can a magnet near my phone, damage it?
Post by: Seany on 31/05/2007 09:20:13
So how strong would it have to be?

do you have an old tape recorder? look how small the magnet is that deletes/records on to the tape, it is pretty small.

to wipe or corrupt a flash drive, i think a fridge magnet could do the job if place on to it. i will try and wipe some memory sticks with magnets when i get home.

Make a backup!! [;)]
Title: Can a magnet near my phone, damage it?
Post by: paul.fr on 31/05/2007 14:50:47


Do try - I will be interested in the result, since flash memory is supposed to be an electric charge device, unlike a tape recording, which is a magnetic recording device.

I would also add that the erase head on a tape recorder is not only extremely close to the recording media (actually in contact with it), but actually uses an oscillating magnetic field rather than constant magnetic field you would get on a permanent magnet (I am not saying that the tape would be impervious to a constant magnetic field, but is more susceptible to an oscillating field, so the deletion can be done more completely, and with a lower flux, than would be necessary with a permanent magnet).

I realised my error as i posted, but what the hck we all mak mistakes. so i left it, it also has contradictions in just two lines! Oh well. Any way, i thought i would give it a try anyway.

USB Flash drive, no damage or corruption of the data from either a small or large (1 inch square) fridge magnet. SD Memory card, no change with fridge magnets of any size.

Then i sat them on a speaker magnet, no change with the usb flash drive. sd card corrupted.
Title: Can a magnet near my phone, damage it?
Post by: another_someone on 01/06/2007 12:35:52
Then i sat them on a speaker magnet, no change with the usb flash drive. sd card corrupted.

Are you talking about simply resting it on a permenant magnet from a speaker, or are you talking about a loadspeaker that was actually being used (and thus have an oscillating magnetic field driving the speaker)?
Title: Can a magnet near my phone, damage it?
Post by: paul.fr on 01/06/2007 14:54:05
I actually tried it with the speaker on, no change, then placed it directly on the magnet and it was corrupted! Does it mean anything?

It was afterall an old card, and doing both could have been a factor. I did not have another spare to do one on each so perhaps it was a factor that both were done on the same card. So the result may not actally count for anything! (sad face icon)
Title: Can a magnet near my phone, damage it?
Post by: CliffordK on 08/12/2010 04:30:47
Blackberry uses a small magnet as a display on/off switch.

I have a cell phone case that uses a flexible "refrigerator type" magnet as a closure.

I'm not sure about using a really big magnet next to your cell phone, but a small magnet won't do a lot.  I would leave the cell phone behind if you are getting an MRI.  A touch display, or pressure on the display may be problematic too, but most modern phones are quite robust.

As far as drives.  Your hard drive will have an electric motor developing a magnetic field, and well as a magnet in the arm. 

I have an electronic degausser.  It takes a pretty gnarly magnet to wipe a hard drive.  And, the power of the magnet falls off with the distance, so if you are 1/2" from the platter, it will take quite a bit.  I wouldn't worry about ordinary household magnets around your computer. 

Old floppies and tapes are weaker than the hard drive magnets, and you can actually touch the recording media.  You might be able to damage them with a good sized permanent magnet.
Title: Can a magnet near my phone, damage it?
Post by: techmind on 08/12/2010 22:49:38
I think it very unlikely that you'll cause any permanent damage to a normal mobile phone by putting small magnets near it.
I might define "small" as in any magnet which, if it sticks to something, you can pull off with two fingers (or finger plus thumb).

If you had a really strong magnet then you might damage the magnet in the earpiece/speaker and permanently reduce the volume and/or cuase distortion. A really big magnet might literally pull things apart inside the phone.


It does very much sound as if your phone uses a Hall Effect sensor or reed switch to know when it's open or closed. If you have an iPhone with built in (solid-state) compass you can really confuse that by putting a magnet near it. Again as long as the magnet is small (as per my definition above) you're exceedingly unlikely to do any permanent harm.
Title: Can a magnet near my phone, damage it?
Post by: maffsolo on 09/12/2010 03:36:34

If you had a really strong magnet then you might damage the magnet in the earpiece/speaker and permanently reduce the volume and/or cuase distortion. A really big magnet might literally pull things apart inside the phone.


I thought Cell phone uses piezoelectric device interface
Title: Can a magnet near my phone, damage it?
Post by: SeanB on 09/12/2010 16:39:54
 a cellphone  has at least 3 magnets in it, one in the earpiece, one in the external speaker and another one in the vibrator motor. A strong fiels will damage the phone, or if it is strong enough ( if you are so moronic that you will take it into a MRI scanner room it will be ripped to shreds) it will demagnetise these magnets.

As to digital media, a CF card can be a small hard drive ( or an original iPod can be as well) but most nowdays are reliant on storage via flash memory, most of which relies on storing charge inside an insulator inside the chip. These are unaffected by a magnetic field unless it can actually induce sufficient current into the system to burn it out. Other types use ferromagnetic solid state storage, which can be erased with a magnet. Those will have a warning in the original instructions somewhere.

Title: Re: Can a magnet near my phone, damage it?
Post by: WarlockInd on 25/10/2013 04:21:09
What about the magnet on my phone case?
Title: Re: Can a magnet near my phone, damage it?
Post by: MrVat7 on 21/01/2014 22:58:11
My touchscreen got malfunctioned by a magnet.
Title: Re: Can a magnet near my phone, damage it?
Post by: AdrianJC on 25/01/2014 20:11:17
So how strong would it have to be?

A lot stronger than the magnetic field within an MRI (http://www.youtube.com/watch?v=XdVqy3Il_mg). Commercial MRI machines use a non-oscillating magnetic field of about 1 to 3 Telsa (http://en.wikipedia.org/wiki/Tesla_%28unit%29) in strength.

However, an oscillating magnetic field of sufficient magnitude and frequency could potentially induce high potentials and generate eddy currents within the cellphone's electronics as to cause damage. I would not try charging a mobile phone by placing it on top of an induction cooker (http://chasetechnology.blogspot.co.uk/2012/11/induction-cooker-can-charge-lumia-920.html).
Title: Re: Can a magnet near my phone, damage it?
Post by: Greyebrage on 08/12/2014 09:34:32
This blog posts attempts at explaining that you really need a very large magnet to really do any damage, and it goes through each component...
http://blog.imagnetmount.com/why-magnets-wont-damage-your-smartphone-electronics-and-data/

In this video, this guy has a large magnet around the phone, kinda funny vid.
Title: Re: Can a magnet near my phone, damage it?
Post by: Oceanbliss on 16/12/2014 08:23:22
It probably depends on how powerful your magnet is... I once put it on my monitor and it caused weird psychedelic behaviors... not my monitor is a drug addict because all it sees is colors... Seriously... its un useable... because i did it for too long haha