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Monday, May 8, 2023

How to make a metal detector using ATMEGA328P / Software based detector


 How to make a powerful homemade metal detector

If you love DIY and adventure, one of the best instruments you can have is a home metal detector. With it you will not only have fun traveling the countryside in search of "hidden treasures", but you will also have fun assembling this device with your own hands and following a few simple steps. To do this, there are several methods to do it, although some offer to use an old radio that you do not use, but the results obtained will not be as good.


This item offers a more professional metal detector with higher power which allows you to detect small metal parts or deeper ones. This will save you from investing a large sum of money in a metal detector, the price of which can vary considerably. For example, you can find very cheap ones that will give bad results for around 40 to 4800 € in some professional products.

This can be good for locating metals that aren't too far away or even checking cables in the wall before drilling and getting a good scare...


Materials needed

The materials are very cheap and you can find them at home:


Battery-powered portable radio that supports AM frequencies. Can be any cheap radio that you can have at home without using or owning one. It shouldn't be a big deal...

Inexpensive portable calculator, it doesn't have to have any special features either.

Ribbon, it can be insulating or American. It's just a matter of linking the devices.

A long stick, such as a mop, a broom, an unused selfie stick, a stick or, if you prefer, an adjustable length stick of those used by painters.

Others: if you prefer to adjust it to your needs, you can equip it with a padded handle, or whatever you need.

Step by step building

Once you have all the elements, the construction is very simple by following these steps:


The wave transmitter used will be the calculator. When connected, it will emit waves that will collide with metal and make the radio tuned to AM sound different when you find metal. Therefore, you need to glue the two components together and in such a way that you can activate them easily.

Once assembled, you need to make sure the radio is at full volume so you can hear the oscillations well. If it detects metal, the noise it will make won't be too loud, so it's best to do it in a quiet environment.

Make sure that when you plug in the calculator, there is interference on the radio. This is why they must be very close together and well fixed with the adhesive tape. Try this by bringing a metal object close and seeing how the radio noise is changed, it will be the same effect that occurs when scanning in the field.

Finally you can add a long stick attached to these two devices to search more comfortably without bending over, although if you are going to use it for walls you may prefer to leave it without a stick...

Is a good option to go out in nature and discover gold metallic veins next to rivers, or just look for things that someone has lost or buried there...


Su operation is simple. How are you going to have a capacitor and an inductor in series, and when a metal approaches the inductor, and changing the magnetic permeability of the core of the inductor, causing a change in inductance and in turn a change oscillation in the circuit. The oscillation before and after the inductor are 180° out of phase with each other, as in a Colpitts oscillator. It will be in charge of generating a constant frequency for the metals to change it and an audible tone will sound.


The Arduino board will take care of processing the signal instead of using a second circuit to compensate for the oscillation. The Arduino board will store the fixed frequency and continuously compare the detection circuit's input frequency with the stored frequency to see if there are any variations (metal is detected).


Materials needed

As a final clarification, say that if you set it to the lower sensitivity, it will be able to detect large metal objects such as soda cans, cell phones, work tools, etc., from a few centimeters deep. But if you set it to high sensitivity, it can detect small metal objects like rings, screws or coins.currency at the same depth. If desired, you can increase the magnetic field area of the inductor by increasing the current flowing through it, i.e. by increasing the oscillator input voltage or increasing the number of turns wire from the spool...


 How to make a powerful homemade metal detector

If you love DIY and adventure, one of the best instruments you can have is a home metal detector. With it you will not only have fun traveling the countryside in search of "hidden treasures", but you will also have fun assembling this device with your own hands and following a few simple steps. To do this, there are several methods to do it, although some offer to use an old radio that you do not use, but the results obtained will not be as good.


This item offers a more professional metal detector with higher power which allows you to detect small metal parts or deeper ones. This will save you from investing a large sum of money in a metal detector, the price of which can vary considerably. For example, you can find very cheap ones that will give bad results for around 40 to 4800 € in some professional products.

This can be good for locating metals that aren't too far away or even checking cables in the wall before drilling and getting a good scare...


Materials needed

The materials are very cheap and you can find them at home:


Battery-powered portable radio that supports AM frequencies. Can be any cheap radio that you can have at home without using or owning one. It shouldn't be a big deal...

Inexpensive portable calculator, it doesn't have to have any special features either.

Ribbon, it can be insulating or American. It's just a matter of linking the devices.

A long stick, such as a mop, a broom, an unused selfie stick, a stick or, if you prefer, an adjustable length stick of those used by painters.

Others: if you prefer to adjust it to your needs, you can equip it with a padded handle, or whatever you need.

Step by step building

Once you have all the elements, the construction is very simple by following these steps:


The wave transmitter used will be the calculator. When connected, it will emit waves that will collide with metal and make the radio tuned to AM sound different when you find metal. Therefore, you need to glue the two components together and in such a way that you can activate them easily.

Once assembled, you need to make sure the radio is at full volume so you can hear the oscillations well. If it detects metal, the noise it will make won't be too loud, so it's best to do it in a quiet environment.

Make sure that when you plug in the calculator, there is interference on the radio. This is why they must be very close together and well fixed with the adhesive tape. Try this by bringing a metal object close and seeing how the radio noise is changed, it will be the same effect that occurs when scanning in the field.

Finally you can add a long stick attached to these two devices to search more comfortably without bending over, although if you are going to use it for walls you may prefer to leave it without a stick...

Is a good option to go out in nature and discover gold metallic veins next to rivers, or just look for things that someone has lost or buried there...


Su operation is simple. How are you going to have a capacitor and an inductor in series, and when a metal approaches the inductor, and changing the magnetic permeability of the core of the inductor, causing a change in inductance and in turn a change oscillation in the circuit. The oscillation before and after the inductor are 180° out of phase with each other, as in a Colpitts oscillator. It will be in charge of generating a constant frequency for the metals to change it and an audible tone will sound.


The Arduino board will take care of processing the signal instead of using a second circuit to compensate for the oscillation. The Arduino board will store the fixed frequency and continuously compare the detection circuit's input frequency with the stored frequency to see if there are any variations (metal is detected).


Materials needed

As a final clarification, say that if you set it to the lower sensitivity, it will be able to detect large metal objects such as soda cans, cell phones, work tools, etc., from a few centimeters deep. But if you set it to high sensitivity, it can detect small metal objects like rings, screws or coins.currency at the same depth. If desired, you can increase the magnetic field area of the inductor by increasing the current flowing through it, i.e. by increasing the oscillator input voltage or increasing the number of turns wire from the spool...

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