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Author Topic: How Does My Phone Detect Metal ? What Is It Sending Out & Receiving ?  (Read 6971 times)

Offline neilep

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Dearest Metal-Detectorologists,

As a sheepy I of course luff metal and luff detecting it too !...It's all I think about really. I wake up, and then wham !!..the thought about detecting metal monopolises my every waking thought !

So, ewe can imagine my surprise when I found this application that turns my mobile phone into a metal detector. (US Translation service: Mobile Phone = Cell phone..sheesh !!)


Look here it is detecting absolutely no metal inside a potato !





No Metal Inside This Spud




and then ...see here...lots of metal in the frame of this ironing board





A Frame Of An Ironing Board Which Has Metal In It !!


Gosh !!..I am quite literally beside myself with joy here as I detect metal where ever I go ! It even found metal in coins !!...yes !!..it really did !!...and there I was thinking that coins were made from cardboard !




so,

How Does My Phone Detect Metal ?  What  Is It Sending Out & Receiving ?

whajafink ?


Anyway, whilst I await some of your kind comments I am going out back in the field to find some treasure.......I'm lucky because I know hedgerows have phone chargers in them...lucky me eh ?



Hugs and shmishes



mwah mwah mwah


Neil
There Be Metal In There Fields
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« Last Edit: 11/02/2011 19:51:26 by neilep »


 

Offline neilep

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No takers ?
 

Offline RD

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The phone may have a magnetometer (magnetic compass).

Putting a magnetic compass close to iron would make it go wonky. 

Does the phone detect aluminium ?, (try non-magnetic metal kitchenalia or aluminium drink can)

If it detects non-magnetic metal, like aluminium, then the strength of radio signals transmitted-recieved by the phone may be being used to "detect" metal.   
« Last Edit: 13/02/2011 16:48:39 by RD »
 

Offline neilep

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The phone may have a magnetometer (magnetic compass).

Putting a magnetic compass close to iron would make it go wonky. 

Does the phone detect aluminium ?, (try non-magnetic metal kitchenalia or aluminium drink can)

If it detects non-magnetic metal, like aluminium, then the strength of radio signals transmitted-recieved by the phone may be being used to "detect" metal.   

Thansk ewe RD...

yes the phone does have a compass thingy.....I did the experiment and it quite happily picks up aluminum too....so..it must be a signal thing.......thanks again !

 

Offline Bass

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 Neil

I suspect your phone has a small magnetic coil of some sort that acts as the compass.  Most metal detectors use a coil to generate a magnetic field, then measure the changes in that field created by nearby metallic objects. 

I have a VLF (Very Low Frequency) metal detector that is good up to about 10' (that's a bit more than 3 meters for the metrically non-impaired) in non-metallic soils and is pretty good at discriminating different types of metals.  I also own a VLF detector, which is a geeky gadget that uses the VLF radio waves generated by the US Navy to help them detect submarines.  It does a great job of finding buried locomotives and school buses, as well as buried pipes and sometimes faults- but not terribly useful for mineral exploration.

Try your phone under some high voltage lines (but don't blame me if your new phone spouts flames) :o
 

Offline neilep

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Neil

I suspect your phone has a small magnetic coil of some sort that acts as the compass.  Most metal detectors use a coil to generate a magnetic field, then measure the changes in that field created by nearby metallic objects. 

I have a VLF (Very Low Frequency) metal detector that is good up to about 10' (that's a bit more than 3 meters for the metrically non-impaired) in non-metallic soils and is pretty good at discriminating different types of metals.  I also own a VLF detector, which is a geeky gadget that uses the VLF radio waves generated by the US Navy to help them detect submarines.  It does a great job of finding buried locomotives and school buses, as well as buried pipes and sometimes faults- but not terribly useful for mineral exploration.

Try your phone under some high voltage lines (but don't blame me if your new phone spouts flames) :o

Fantastic info..Thank ewe ver much BASS !...have ewe ever found some really nice finds ?

I appreciate the info regarding my phone and if I do go play with the metal detector beneath some pylons I will blame JimBob !...cos everything is his fault anyway !  ;D
 

Offline Don_1

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Good grief! A mobly fone with a metal detector, whatever next?!

Eureka, I've got it, a mobly fone that makes phone calls, now that's what you call a novel idea.
 

Offline teragram

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Is it possible that metal in the vicinity of the phone will absorb energy from the phone’s antennae, resulting in a change in current in it’s output stage?
If so, then this could be translated into a reading on the phone's display.
 

Offline Geezer

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Is it possible that metal in the vicinity of the phone will absorb energy from the phone’s antennae, resulting in a change in current in it’s output stage?
If so, then this could be translated into a reading on the phone's display.

I think that's the most likely reason. Thanks to mutual inductance, the chunk of metal will lower the impedance of the phone's antenna and pull more current from the drive circuit.
 

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