Magnetic phone holder for car. by protoman
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I wanted to put my HTC Hero on my new car but I didn't found a phone holder that fits with this phone due it's a little curved where the buttons are. I've already found a good car holder, but a little expensive (19€). It's a magnetic holder made by an Italian company:http://www.tetrax.com/en and taking the idea of a magnetic holder I decided to make it by myself.
The result is a magnetic car holder that fits with any phone with a battery cover (sorry iphoners) and in any position without making any hole and with a very powerful magnetic strength.

Materials:
- Old hard drive or flat neodymium magnet.
- Cutter blades.
- Double side tape, thick for place the magnet in the car, thin for place the blades in the phone.

Let's start:

 
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Step 1: Get the magnets.

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I've disassembled  and old 3.5" hard drive and there are two neodymium magnets to drive the reading arm. To detach it from the metal plate you can bend this support with two strong pliers, it will pop out due it's only glued. I've used the two magnets together due the magnet force its higher. It's not necessary to glue them, they are magnets!
Be very careful with this magnets, they are very strong and you could hurt a finger by placing it in a metal part, or you can delete any credit car near them.
kondzio29 says: Jul 7, 2012. 4:08 AM
I thing you should check your gsm signal after doing it, because it can cause lower range of signal...
lilonex3 says: Mar 27, 2012. 11:48 PM
You said everything works fine with this setup.I have a few hdds I might scrap just to do this for my car and my work truck.This dont affect the navigation on the phone? you said only the compass so wondering if it will still work.I use my phone for navigation if I go somewhere I havent been before.

Thanks
protoman (author) says: Mar 28, 2012. 12:37 AM
The compass will be fixed to one direction due the magnet, but the GPS and all the other radio signals will be work ok, but you must try it with your phone.
elbel86 says: Jan 30, 2012. 8:45 PM
I used a similar setup. I taped a small metal washer inside my silicone case then slipped it on the phone. It is small enough that the compass seems to work just fine, but large enough to hold strongly to the hdd magnet I used. Of course the compass does not work when mounted, but thats why my Jeep has a compass on the overhead info panel.
ggrigoryan says: Nov 27, 2011. 9:33 AM
don't you think that magnetic pole can in long term destroy some details inside?????
M1LL3RT1M3 says: Nov 5, 2011. 4:16 PM
My initial thought was with the blades. Imagine what TSA would do to you if they ever caught those while trying to board and aircraft. Hope you don't have any allergic reactions to latex cause it's gonna be a long day.
mr.incredible says: Jan 22, 2011. 10:16 AM
I've been doing almost the exact same thing for 3-4 years. I made custom fit metal plate that covers most of the back of the phone. Like protoman says, the only thing affected is the compass. I have even tested the compass almost a year. without the metal back on it everything works great. No long term effects. The neo magnets from a hdd are strong enough that I never have to worry about the phone falling off. I can almost throw the phone up there and it will catch it. No fumbling around trying to find your mount. When you aren't using it for the phone, the charge cord will happily hang there.

One thing I would add. I cut a piece of rubber from an old bike innertube, and I super glued it to the magnet. I then trimmed it with a exacto knife. It gives the phone a little protection from scratching. It also give a little better look than just the shiny magnet.

If you use the household/plummer/marine goop glue, it will cleanly remove later if you wish. You just have to tape it in place for a day or so so it will set up.

I also made desktop cradle with round neo magnets and a piece of heat bent lexan. Drill some holes in it and recess the magnets. Cut out a piece of innertube and glue over the magnets.
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protoman (author) says: Jan 22, 2011. 1:42 PM
Thanks for the results of the long term testing. I only have it mounted from 2 months ago but I don't see any future problem with SD or screen like some people say without thinking about it first. The only problem is that I'm detecting a little magnetization of the blades (not enough to hold a clip). This could be a problem due the compass will be wrong all the time, it happen to you also?
mr.incredible says: Jan 24, 2011. 8:18 PM
Yes, the compass is pretty much useless as long as the blades/metal plate is present. Good news is if you remove the metal, nothing is permanently damaged. The compass will calibrate and continue on like nothing happened.

To answer a couple people here, SD cards are not a magnetic medium. They are solid state circuits. Magnets do not effect LCDs either. Hold a magnet up to your LCD monitor. (carefully) there is a metal shield on the back. It will attract to your magnet and you could break the glass front. (strong magnet)

The accelerometer is not affected either.
eygen says: Jan 14, 2011. 1:05 PM
I have to agree with Mike and tell you that this is a bad idea.

A magnet near electronics is a bad idea in the first place, but the SD card in your phone is particularly sensitive to magnetic fields.

You're also using blades for something that isn't cutting (which in my opinion is a bad idea).
protoman (author) says: Jan 14, 2011. 3:48 PM
The only problem is with the compass, that don't work well. The mobile signal, bluetooth, position sensors, accelerometers, etc works fine. I put the phone every day almost 2 hours in the magnet and works perfect from a month ago. The electronics have problems with the electric fields, not the magnetic fields. The magnetic fields can generate a voltage if this field changes in time, but in this case the magnet it's fixed. And "the SD card in your phone is particularly sensitive to magnetic fields." in 19 years studying  and working with electronics never listened something like this, could you explain in what is based this argument?
I use blades because they have a good level of iron and work well with magnets, you could say another cheap and thin material instead this.
silencekilla says: Jan 15, 2011. 6:19 AM
the magnet can also corrupt memory in the phones database and if left there long enough damage the crystal or lcd display on the phone. This is not a good idea at all. also the razor blades are just a horrible idea especially in a car lol
protoman (author) says: Jan 15, 2011. 10:02 AM
The magnet doesn't affect the memory or lcd, please could you explain why you say this? The razor blades are inside the battery cover, you don't see or touch them, please read carefully before say something is a horrible idea.
mrbob1000 says: Jan 14, 2011. 1:33 PM
SD cards are flash based and therefore not sensitive to magnets like floppy disks or harddrives that are magnetic. I dont see anything that would be a problem with the magnet.
mikedoth says: Jan 14, 2011. 12:58 PM
So why doesn't the magnet hurt the phone, espeically the SD card?
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