Hurricane season is rapidly approaching those of us who live in the northern hemisphere. While that does come with a good deal of stress for any homeowners who live in the potential paths of storms it also comes with some opportunities for treasure hunting. Storms tend to wash up all kinds of things from the sea, and if you are equipped with this DIY metal detector you could be unearthing all kinds of interesting tchotchkes from the depths this year.
The metal detector comes to us from [mircemk] who is known for building simple yet effective metal detectors. Unlike his previous builds, this one uses only a single integrated circuit, the TL804 operational amplifier. It also works on the principle of beat-balance which is an amalgamation of two unique methods of detecting metal. When the wire coils detect a piece of metal in the ground, the information is fed to an earpiece through an audio jack which rounds out this straightforward build.
[mircemk] reports that this metal detector can detect small objects like coins up to 15 cm deep, and larger metal objects up to 50 cm. Of course, to build this you will also need the support components, wire, and time to tune the circuit. All things considered, though it’s a great entryway into the hobby.
Want to learn more about metal detecting? Check out this similar-looking build which works on the induction balance principle.
There’s also a video by diodegonewild with similar overlapping coils: https://www.youtube.com/watch?v=eCRgNr6jj2g
I’ve always liked playing with metal detectors, although it can be difficult to ascertain exactly where you’re allowed to use them, not to mention difficult to track down land owners to ask for permission.
On aa complete tangent, I do wonder about the choice of,”tchotchkes”, certainly an interesting word, but it appears to be different from the overall style of the writing, it seems like HaD sometimes adds one stand out word, almost in the same place in each of the articles. Is it accidental, purposeful as a learning experience or some sort of secret messaging service or hidden easter egg puzzle? It’s quite intriguing, almost like the patterns that seemingly, accidentally, appear in quiz show answers on occasion.
It’s to hook you in, and it worked!
Make two small ones and put them in your shoes. Then attach it to a data logger with a gps. You could make a heat map of everywhere you walk. Ground resistance or it maybe even an option to do that with radar, as those modules are getting pretty cheap these days.
Keep in mind that in some EU countries (eg Poland) posession of metal detector without valid archeological license (issued by university or goverment) is a crime punishable by up to 2 years in prison.
So you can’t even try to find coins that fall out of pockets on a beach?
I’ve seen lots of people with metal detectors searching for coins on polish beaches. I wonder if they all have archeological licenses…
Wow! That is quite surprising to me. It seems such a harmless thing to be regulated so tightly!
Here in the US the only thing metal detectorists have to worry about is trespassing (as far as I know).
> have to worry about is trespassing
In some states that means that you have to worry about being shot, isn’t it? :)
actually in most states….
And rightly so.
Trespassing isn’t something a person should be murdered for. Why do Americans think murder is the response to every nonviolent minor crime whether intentional or not? Is it that there are more guns than people in the country?
Because we’re all psycho. This is just one example. Don’t F with us.
funny that the chances of you or one of your family gets killed by a gun increases the moment you bring a gun into the house.
Unfortunately most states have laws against using them in a lot of areas
Basically due to archeology laws stating you can’t remove anything over 100 years old ..
Topped off with folks who dig holes And are to lazy to fill them back up.. in parks, so cities say No !!
Most of my metal detector experience is finding buried utility vault lids, for which they’re invaluable. Hopefully Poland and others have a carveout for this appliction.
Carl & Jerry, the fictional duo in Popular Electronics, built a magnetometer to find “buried treasure” on a farm. They mostly found junk, farmers burying their own garbage. It’s in the April 1964 issue. Not a howto article, but it presents the basics, and there must be more howto online.
https://worldradiohistory.com/Archive-Poptronics/60s/64/Pop-1964-04.pdf
I’ve always assumed that their fictional school, Parvoo University in Indiana is based on Purdue University, my Alma Mater.
If you meddle with the electronics a bit, this can probably do a fair-to-middling job. No need to mudde around too much, though.
(“muddle”)
And you would’ve got away with it, if it wasn’t for that meddling otto carrot!
B^)
The northern hemisphere isn’t blighted by hurricanes, unless you happen to live in the eastern USA or on some caribbean island. The majority only get to read about them.
This ignores eastern Asia and India. They just call them typhoons.