Make your own Metal Detector for free
What you need: A CD case (or other support), some kind of adhesive, a Calculator, an AM-FM Radio (with headphones) and a pole.
Step one: Empty the CD case. You will use only the transparent covers.
Step two: Mount or glue the calculator and the AM radio to the CD case. How? Close the CD case and open it. Now glue the AM radio to the cover but on the back, and glue the calculator to where the CD used to be.
Step three: Turn on the calculator and the radio.
Step four: Tune the Radio to the highest AM. You should hear static.
Step five: Slowly close the CD case making the calculator and the radio come closer. Once they are at approx 20 to 45 degrees you should hear a loud tone. That is the tone that will indicate metal presence. Remember it.
Step six: Now separate the CD case. Leave it at an angle of approx 45 degrees and glue the CD case. It should be fixed at that position. Slightly opened. The Radio and the Calculator should face each other at approx 20 to 45 degrees. When turned on, you should hear nothing, and the radio should be set to the highest AM frequency.
Step seven: Now glue a light plastic pole to the CD case support. Don’t use metal poles, of course. The pole will help you scan the ground surface.
Step eight: Connect the headphones, turn on the radio and the calculator and go fishing for metal.
How does it work?
The radio and the calculator create a tone when they become in contact. You have heard this tone when you put the Calculator close to the radio (step five). Once you separate it, the tone is gone, but in the presence of a metal the void or gap will be filled with a sound. Just like a switch works when it is turned on. The tone would switch on the system and it will make the tone indicating the presence of metal.
If this is too simple for you and you are looking for more professional metal detectors you can go to Easy Treasure, www.easytreasure.co.uk/bfo.htm. They have a more elaborated designs.
This article is not responsible for readers interpretations. This article does not represent any group or organisation. This article is not responsible for readers experimentations. Safe and responsible metal detection is encouraged.