If you have been trolling the Internet for how to videos on sites like youtube and metacafe you may have heard about the video of how to make a metal detector from a radio and a calculator. You probably then wondered if such a trick really can work. Well if you don’t know the trick this article will tell you how the trick should work. If you want to know if it will work I will tell you what I have seen when trying this trick myself.
The idea from the video is actually a very old idea that has been around for many years and been seen in many older books and recently revived with the Sneaky Uses for Everyday Things series and even more recently revised with the introduction of the metacafe video showing a method as well as a sequel showing a second method.
The method used follows a simple loop system as used in early metal detectors like from WWII. The same idea was first shown in popular science magazines during this era but instead of using items you already have you had to make the thing with some wire and other parts and it was much bigger.
What you need is an AM radio which is hard to find, sure you can get a mini FM radio from the dollar store but its hard to find AM radios on there own anymore, this is probably one of the reasons this video has been so popular because it is hard to test unless you want to go about looking for the items. Next you get a calculator. A simple explanation of what you need to do is to tune the radio to the high end of the band; you need to find a frequency that does not have a station just static. Next you have to put the calculator over the radio and turn on the calculator. Then you pass it by metal and it should beep.
So does this trick work. Well in theory it should just because many electronics not just calculators but other devices like remote controls have the same electronic loop that also works with the radio like the two different frequencies used in a metal detector. I have tried this trick as shown by the online video and have used various calculators and radios but I found that it almost never works and that when it does it is very weak. You can improve the signal by using aluminum foil but even then it is not practical and will never come close to a professional metal detector.
There is another video that shows how to remove the calculator or other electronic device but this seems to be completely fake. Based on my electrical background there is no reason that using a DVD, CD and a radio should make a metal detector the only theory I can come up with is that it radio signal bounces off the disc but that still does not seem to make sense so I have not wasted any DVDs, CDs, or headphones to test this absurd system.
