Radio+tape+calculator=metal detector
- by Francesca Clarke on Nov 29th 2007 8:00AM
- Filed under miscellaneous, geek it yourself
This homemade metal detector is one of the easiest projects I've seen. All you need is an AM radio, tape, and a calculator. You don't have to take anything apart or follow any complicated directions, all you do is tune the radio, stick them together and let the reaction happen. As your device moves close to the metal object the radio waves from the calculator reflect off the metal and are heard as a loud beeping on the radio. The beep is intensified as you move closer to the metal object just as it would on a commercial metal detector.
Hack together one of these next time you're searching for a hidden treasure, or just give it a try for fun. The video results are impressive and it uses materials you have, takes little time, and is super simple.
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Reader Comments (Page 1 of 1)
12-06-2007 @ 12:26AM
Thomas said...
I call BS. AM radios don't broadcast. And at that as it gets closer. Metal detectors work by sending an electromagnetic towards the target, if their is metal the magnetic field is reflected back to a sensor in the detector and then hardware decodes the signals and represents the strength on a display and/(or) via an auditory tone.
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12-22-2007 @ 4:07PM
GG said...
No you're full of BS. An AM radio has a Intermediate Freq. (IF) oscilator which hetrodynes with the incoming siginal to produce a 455kc intermediate siginal which is then detected, retified and amplified to produce the audio . That is why most Am Radios are called hetrodynes.
Now for the Calulator it also has an oscillator circuit in the CPU. The Am radio tuned to the freg of the Calculator produces a null or hetrodyne siginal which when upset by the maganetic interference of the target causes an audio beat to be emitted by the AM radio.
GG
CSR 6320
Technician
12-06-2007 @ 8:39AM
Nikolay said...
Thomas, you're right that radios don't broadcast but the radio stations do! The AM radio is just a receiver and I believe it would be possible to detect some disturbance in the field produced by AM radio stations when near metal object. AM radio stations broadcast between 153Khz and 26.1Mhz and a lot of metal detectors work on frequencies at about 15 - 300Khz. That's why you should tune the radio to long waves (as close as possible to 153Khz). I'll give it a try ;)
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12-08-2007 @ 12:13PM
Kevin Lay said...
How Macgyver.
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12-10-2007 @ 1:02AM
Jeice said...
Thomas, You obviously didn't look at what he said or at what the video explained. The calculator is what's giving off the signal. The radio is what's picking it up.
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12-10-2007 @ 7:45PM
zazzy said...
In what language did the author speak?
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12-11-2007 @ 1:10AM
Random said...
i believe he spoke in lithp
12-13-2007 @ 1:47PM
Seth said...
Omg, so much win in comment number 6.
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12-16-2007 @ 4:28PM
Rick White said...
It absolutely works. You can make a media player out of TI-83s by putting a radio set to any "staticky" AM or FM channel next to it and running different loop commands in a program. Depending on how hard the processor on the calculator is working will change the tone on the radio. You can play with while-loops and putting random commands in them to change pitches or just google around to find pre-made music players.
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1-06-2008 @ 5:22PM
Jordan said...
i am trying to do this fo ra physics project but it doesnt seem to work, i am using a staples electronic calculator and a dualband radio. I can't seem to tune it till ig et the tone, any help please?
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1-06-2008 @ 9:04PM
jagergenbergen said...
so that tone comes from hitting a button on the calc, try it... i did
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1-06-2008 @ 10:39PM
Jordan said...
REALLY :O ill try it...thanks
1-14-2008 @ 1:19AM
Jordan said...
i am still having problems to get mine to work. I think i fried one of my calculator circuit boards LOL
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2-22-2008 @ 5:51AM
James said...
Wow, didn't know it was so easy to make a metal detector. Will see if I can get one working.
Thanks,
James
http://www.treasure-hunting-research.com
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6-11-2008 @ 1:33PM
Joe'scrabs said...
LOL, that was really funny, especially all the people believing you
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