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Home Made BFO metal detector

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Step 5: Tune it up!!!!

Now that everything had been installed onto the body and the detector now looks more like somethign is time for the finishing touches. turn it on and listen for noise. Then screw the screw into the canister slowly and listen for change. If the tone goes higger, you are good. If you put it all in and nothing changes, you need more metal. One way to test this is to shove a big piece of metal inside the pick up coil, if you see a change and in some point beeping then you need more metal. IF it gets worse, then you have too much inductance, and the search coil is under inductance. try adding some screws to the detector plywood boddy. you have to get both inductors at same frequecy. with mine i needed more metal inside my pick up, and what i discovered is that metal close to the coils will change it more than in the midle of the canister ( like the screw). So now get those washers and nuts and put them inside the canister. Push them in until you get the sweet spot. then get some superglue and glue them there. this will add a lot of induction to your coil. then use the small screw to adjust it tight.

There's a lot of playing arround in this area, the better you make thigns the better they will work. IF the screw is too loose then it will go in and out of frequency all the time, this hapened to me and i'm in the process of re-engineering it. hoep it helps sned any Questions I'll try to help.
 
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RaniaMomo2 years ago
thank you sooooooooooooooooooo much
kiko234 years ago
how deep it can register metal ?? 
JoelDude (author)  kiko234 years ago
it depends how large is the metal and how deep it is, and what type of metal. I bet it would detect uranium easier than aluminum. this is a very very primitive metal detector, so dont expect much of it. modern one's have automatic tunning and will tell you how deep things are n whatnot.

If a modern metal detector is a 3 ghz computer, this is a basic calculator, not even a TI-83
ducguedes4 years ago
yeah !! it works !!!!
 tks !!!!
rishthedish5 years ago
How cool! Im going to give this a go. I want to give my honey a metal detector for Xmas.
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