Accessories Kindle in a purse with two magnetic closures

[fugazied]

Unless they are super strong magnets you are unlikely to see any issue with a Kindle.

[HarryT]

Originally Posted by scotty1024

Wow. That's a pretty blanket statement to make there Harry especially considering you're absolutely wrong.

The term for what the magnets can do is Electro Magnetic Interference or EMI.

Magnets can and do interfere with cellphones. The Kindle has a cellphone radio in it.

With the greatest respect, scotty, I have to disagree with you. I do have a PhD in physics, I should perhaps point out. The very weak magnets used in clasps are not going to cause any noticable interference to anything.

... and, as others have already said, static magnetic fields do not cause "EMI". A static field does not broadcast any energy. Only fields with changing flux do so.

[andrew_capulet]

hi everyone,

my first post, so please be gentle!

we make Amazon Kindle 3 purses with magnets. To date, there have been no issues with any magnets whatsoever in our cases, both in our own testing as well as zero customer issues.

To give you an idea of magnet placement etc, here's a photo:


If you'd like to see more of them, you can find them here: http://www.capuletlondon.com/boutiqu...her-cases.html

[kacir]

Originally Posted by andrew_capulet

we make Amazon Kindle 3 purses with magnets. To date, there have been no issues with any magnets whatsoever in our cases, both in our own testing as well as zero customer issues.

I will try to be gentle ;-)

I see one huge issue with the magnet as shown. Not with magnetic field, but with placing it directly above the center of the screen. The screen is THE most fragile part of the device. Screen is THE thing that the case is supposed to protect. This case works as a focus for the force applied to the front of the case/kindle, directing it to a small spot in the center of the screen.
An example.
If you place "naked" kindle between two books and press them together, nothing will happen. When you place kindle inside your cover between two books and apply a little bit of pressure, the result would be cracked screen.

This is the issue with the vast majority of cases I have seen. Why do you make super thin gadget and thin case, only to double the thickness by placing large magnet with fastening strap right on the top?

I used to grumble about the case Sony PRS-500 had, yet it is the best case for reader I have ever seen. The device is held in by a large snap connector at the back of the device and the cover was held closed by magnets located inside the reader. No clunky holding straps, no large magnets or straps doubling the thickness of device in cover.

[pilotbob]

Originally Posted by kacir

I used to grumble about the case Sony PRS-500 had, yet it is the best case for reader I have ever seen. The device is held in by a large snap connector at the back of the device and the cover was held closed by magnets located inside the reader. No clunky holding straps, no large magnets or straps doubling the thickness of device in cover.

I agree... the PRS-500 cover and cover mounting system was da bomb! I have no idea why the did away with it.

BOb

[Mark Rehorst]

Originally Posted by scotty1024

Wow. That's a pretty blanket statement to make there Harry especially considering you're absolutely wrong.

The term for what the magnets can do is Electro Magnetic Interference or EMI.

Magnets can and do interfere with cellphones. The Kindle has a cellphone radio in it.

No. Static magnetic fields produced by permanent magnets do not cause EMI.

Originally Posted by scotty1024

While the magnets jamming the cellphone in the Kindle won't make anyone miss an important call they can raise the noise level for the radio causing it to pour on more power to reach the network clearly.

More power means a shorter time until it must be re-charged. A Kindle battery only has so many charge cycles in it before it must be replaced.

So if hauling your Kindle around next to magnets results in your Kindle needing a new battery earlier than otherwise? I call that harm Harry.

No. The magnet will have no more effect than having the device in a bag and close to the body. If the magnet were placed right over the antenna (wherever that is) it may cause some detuning by a capacitive effect which could reduce its performance, but it would make no difference if it were a magnet or not. Almost any dense/metallic object placed over the antenna will have the same effect. Placing a cell phone in your pocket does the same thing because your body detunes the antenna.

As for battery life, your comment is a pretty extreme stretch of reality. The Kindle doesn't continuously connect to the cell network and constantly send data back and forth. It occasionally attempts to connect. If it fails a few times it stops trying for a while and and tries again later (like maybe tomorrow). If it did not behave this way people who leave the radio on and go out of range of a cell system would report dead batteries in a matter of a few hours. I have never seen such reports. Also, few people leave the radio on all the time in order to extend battery charge life because they recognize there's no reason to leave the radio on all the time. The addition of magnets to a case latch will NOT affect anyone's battery life.

Originally Posted by scotty1024

If you are worried about SAR, the impact of absorption of the radio waves on your body, having your Kindle broadcasting at a higher power level means more SAR. So magnets could lead to higher levels of absorbed radio power by your body. Not technically harm for the Kindle but if you are genetically pre-disposed to certain types of cancer you might not want that.

There's no science showing that cell radiation causes cancer of any sort. Putting the kindle in a case carried against your body might cause the radio power to increase (assuming the radio works identically to the radio in a phone), but then again, no one leaves the radio on all the time and the radio does not continually connect to the cell network even if you did leave it on. This is a non-issue.

Originally Posted by scotty1024

Anyway that's what I recommend: get purses etc that use flat sheet magnets. Not things that use those button sized rare earth "will hold your body weight or your money back" magnets.

Actually, if you're worried about detuning the antenna in the device, large, flat magnets are more likely to do so than small, strong magnets. Again, the detuning is due to the presence of dense/metallic material in close proximity to the antenna (a capacitive effect), NOT due to the strength of the object's permanent/static magnetic field.

[alansplace]

Originally Posted by kacir

I will try to be gentle ;-)

I see one huge issue with the magnet as shown. Not with magnetic field, but with placing it directly above the center of the screen. The screen is THE most fragile part of the device. Screen is THE thing that the case is supposed to protect. This case works as a focus for the force applied to the front of the case/kindle, directing it to a small spot in the center of the screen.
An example.
If you place "naked" kindle between two books and press them together, nothing will happen. When you place kindle inside your cover between two books and apply a little bit of pressure, the result would be cracked screen.....

[susan_cassidy]

And who the heck is downloading a book with their Kindle inside their purse, even if the magnets could interfere?

[pilotbob]

Originally Posted by susan_cassidy

And who the heck is downloading a book with their Kindle inside their purse, even if the magnets could interfere?

Kindle automatically downloads subscription items. So there could be many people doing this.

BOb

[susan_cassidy]

I seldom leave my Kindle in my purse overnight, which is when most subscriptions download. Maybe some women do.

[kacir]

Originally Posted by susan_cassidy

And who the heck is downloading a book with their Kindle inside their purse, even if the magnets could interfere?

I think I have read reports from owners of a very nice metallic case for Kindle, that the kindle would sometimes crash inside the case. It would be trying to establish WiFi (or 3G, I do not remember) connection and it would crash.

You are supposed to switch the Kindle on in the morning and find fresh newspaper ready for your enjoyment.

[Mark Rehorst]

Originally Posted by andrew_capulet

we make Amazon Kindle 3 purses with magnets. To date, there have been no issues with any magnets whatsoever in our cases, both in our own testing as well as zero customer issues.

To give you an idea of magnet placement etc, here's a photo:

It looks like a great case to me. I agree with others that the placement of the latch puts the screen at risk, if you put the Kindle in the case with the screen side against the latch. The smart user will no doubt simply insert his Kindle in the case with the back side toward the latch and will never have a problem with it.