Smart Hunter EN


The purpose of this project is to make a cheap but effective VLF metal detector. If you want to support the project you can make your donation here! Thank you!


Metal Detector "Smart Hunter"

Metal detector “Smart Hunter” is a project that will help you build a powerful VLF metal detector. This metal detector is based on an Arduino microcontroller and a smartphone. Here you will find all the necessary tutorials. Just follow the tutorials step by step and if you have any questions contact us. This metal detector is able to detect a gold ring or a coin at a distance of 30 cm, a lid of a pot with the diameter of 20 cm can detect at 90 cm! Start now and build your own “Smart Hunter” metal detector!

Premium Version

Premium version is a bit different from the free version because it has an internal generator, so in the Premium version it is not necessary to use arduino nor the MOSFET, which facilitates the assembly. The frequency of internal generator can already be chosen within the app in the PRO menu. The generator can generate from 20 Hz to 20 kHz but to detect what we are going to do we will need only from 4 kHz to 20kHz, because the working frequency of most of the “VLF” metal detectors is between 4 kHz and 20 kHz. The assembly is the same as in the free version, but in the Premium version it is easier for not using the arduino and also cheaper. Operation of the internal generator: internal generator generates the sine wave with the selected frequency and the generator signal goes to the transmitter coil (Tx), but since the signal is weak, we must amplify it, that’s why we use an amplifier.  In the online store Aliexpress there are many different amplifiers, in the video tutorial i use one of those cheap amplifiers. This amplifier is cheap and very easy to use, has only input/output and power “5v” . The receiver coil still unchanged as in the free version. That means that we mount the receiver coil (Rx) as we can see in the schematic, only if we use Premium version we no longer need the arduino part. On the internet there many schematics how to make an homemade amplifier , so if somebody want to build a homemade amplifier it also will work. The amplifier used in this video has output 3 watts , if we are going to use the coil with bigger size then we must use amplifier with output  15 watts more or less  ( depends on the  size of the coil). Below in the section “Free Version” we can find video tutorials how to make the coils and how to adjust them, this assembly is the same for the both coils. ,

The PCB of version 2.0.0

A new version of the PCB has been launched. In the new version 2.0.0 a preamplifier has been added to the receiver coil, which has considerably increased the sensitivity and stability of this MD. When using this version, you must select the  value of the “Rx splitter” 1000 or 500 in the application configuration. You can try an other values, but the tests showed that these are the two most optimal values. You can also try changing the volume of multimedia on your smartphone, since it is responsible for the strength of the signal that goes to the transmission coil. Increase the volume almost to the maximum for more sensitivity. Increasing the sensitivity without losing stability can change the resistance R4. Less than 1.5k, I do not recommend putting, you have keep in mind if we increase the value of this resistance the sensitivity decreases, but the stability improves.

Assemble the PCB and tests (Soon wil be translated):

Schematic of Premium version v 2.0.0

Free Version



Download Arduino sketch and schematic here :

3D coil model for 3D printing.

Here you can download 3D coil model for printing on 3D printer. It’s free! Just download it and it ready to print! Inside the file you can find full 3D model for printers with hotbed bigger than 300x300mm, and also 3D models for printers with hotbed less than 300x300mm. Enjoy! 

110 thoughts on “Smart Hunter EN”

  1. hola,
    me gustó mucho su proyecto y me gustaría felicitarlo …
    ¿podría responderme una pregunta?
    es posible hacer el tx coil 1 sin el “arduino nano” ejemplo hacer una placa sin o auxilio del mismo? utilizando otros tipos de componentes “ci, condensadores, resistores entre otros ….”
    desde ya gracias

    1. Si, por supuesto es posible!Arduino utilizamos como un simple generador de onda cuadrada!
      Si buscas en internet puedes encontrar muchas circuitos para hacer generador de onda cuadrada, solo elige uno que te gusta!
      Uno de los mas populares esta echo con un integrado barato que se llama NE555.
      Tambien hay generadores de onda cuadrada echos con solo dos transistores!

    1. The complect sketch and shematik you can download on this page.Just click “Download arduino sketch and shematik”
      You can get the components from an old electronik divices or you can buy in internet, i buy on Aliexpress it is cheap shop

  2. Please bro .. in the the amplefire shematic there is no small coil .. there is just tx and rx coils i need to know if there is a small col .. and if it been .. how i can connect it ?

    1. Hi!
      The small coil calls “Cx” coil!
      THis coil we need only when you put epoxy resin and the balance is incorrect!
      for exemple you adjust the balance to “100 amp” after fill with epoxy resin your balance go out to “400 amp” so in this way you need to put the “Cx” coil but if your balance is OK you don’t need this small coil.
      THe small coil if you need to put it we connect en series to Rx coil it is like a part of Rx coil. You can see in schematic of Free version there is schematic how to connect Cx coil

  3. Thank you very much for this wonderful work I have done, We ask you to make us a simple metal detector working with the technology pulse induction (PI) pleas …

    1. Hi, you can see in the section “Metal detectors” my new project “Spirit PI”!
      Tjis is pulse induction mrtal detector.
      Soon i will upload the PCB and new update. Thank you!

  4. Hi,
    When we adjust the resonance frequency of the two coils, we put an appropriate capacitor, parallel to the coils. I do not see these capacitors anywhere on the schemes.

  5. Well .. I mean when I plug the phone into the Ndq controller circuit
    The ringing continues from the phone

    Vibration works with a ringtone in that one..This is already a fatal mistake, does not it?
    What is the problem in your opinion

    Greetings to Hashem

    1. Did you make a ground balance? You need press the center of the circle where the big value. Than it will start to balancing, than it will ready to use

  6. Ну, я имею в виду, когда я подключаю телефон к цепи контроллера Ndq
    Звонок продолжается с телефона

    В этом работает вибрация с рингтоном .. Это уже роковая ошибка, не так ли?
    В чем проблема на ваш взгляд

    Приветствую Всевышнего

  7. I think this is problem of connector MiniJack! It must stop detect noise and only detect signal from the coil! You can try to change the MiniJack connector

  8. Микрофон по-прежнему работает. Благодаря этим проводам мой микрофон работает постоянно, и в результате приложение взаимодействует с любыми звуками. Различные варианты Что вы думаете?

  9. Я протестировал MiniJack, что он хорошо работает
    Когда я уравновешиваю свитки, на BCB выдается очень низкая громкость динамика
    Влияют ли конденсаторы?

  10. Christopher Smith

    Hi, This is a really great project, Do you have any plans to implement metal discrimination into the App at some point.

  11. Dear Mr.
    If you can add discrimination mod [specially reject iron] for your smart hunter 2 version i like to buy app. important thing is discrimination among the IB Metal detectors. your work is great. also i hope discrimination spirit PI [next version ]
    many regards

      1. Hello neco
        I pay and downloaded your premium v.2 by google play store. can i make circle coil for it and your coil valuation same for premium version. also here it is no xpt8831 amplifer chip, i have pam8403 [3watts+2channal] chip. can i put it for transmitter coil?

        1. Hello!! Thabk you!yes you can use this amplifier, but what do you mean “circle coil” ?? You can use Double-D coil or concentric coil, but mono coil with only 1 coil inside it not work!

  12. Dear mr.
    when i make rx coil for PREMIUM VERSION, there need or not 2of 1N4148 Diode, 1mf capacitor and 1.5k resistor like a free vorsion ? it is i have a big problem. thank you

  13. Hello I’m one of your followers thanking you very much for your efforts, I have a metal detector garret at pro. I have a problem with my own coil dd. I want to help me in detecting the electrical circuit used in this coil Please please ?

  14. I’m one of your followers thanking you very much for your efforts, I have a metal detector garrett at pro. I have a problem with my own coil dd. I want to help me in detecting the electrical circuit used in this coil please please?

  15. Thank you I have a problem, and the coil dd of garrett at pro is corrupted. I have kept the circuit used in this coil in order to create it instead of buying it?

  16. I have a damaged coil I opened it and found inside it 8 poles of wires Talees, Shiites and Resistants 1.5 ohm and 100 ohm changeable + 100 nano farad! Now I have kept the circuit used in this coil dd at pro in order to get the wires in the correct place and repair it?

  17. Hello, i have Detech 10*12 sef DD 18khz coil. Can i use this coil in project? Thanks for reply 🙂 sorry, first post are incomplite..

  18. Hello. Thank You for Your work. My Smart hunter 2.0 premium not work properly. Can You help me? What value have C1, is it 10 pF? Next question is about amplifier,on schematic I see Sound Channel 3 conected to IN- and Sound Channel 4 conected to IN+ of the amplifier. On Pcb is only Sound Channel +? Please help me understand.

  19. Hello friend thank you very much for all your hard work i just found your site and work online I am trying to build smart hunter new vertion 2.0 but C1-10P what is it, What value is C1 on Premium version, i know someone already ask and R3-100 is that resister 100ohm thanks

  20. Can i use this for smart hunter V2.0.0
    , For c1=10p (50pcs 6KV 10P 10PF High Voltage Ceramic Capacitors)
    thank yoou for all your work

  21. Hola Sergio,te envío uno de los detectores que tengo hecho y funciona muy bien,recordé que querías hacer un pinpointer con el pic12f629 y este detector también usa ese mismo pic y es fácil de hacer con buenos resultados.
    En esa página también hay más detectores con Arduino,attiny,digispark y microcontroladores Pic.
    Espero que os guste.
    Esta en ruso y para ti es fácil NECO
    Espero que no te olvides de los españoles y latinos que te siguen,y subas más vídeos en español


  22. Greeting, thank you for your wonderful project. my question is this possible to use esp8266mod instead of esp32 if yes is it possible to give us the sketch of the latter is the diagram and pcb
    thank you so much

  23. He did everything right – it doesn’t work. I have a Smart Hunter Metal Detector app (DIY Project). Where can I find the right Smart hunter 2.0.0 app.

  24. Smart Hunter software: Noticed new version of 3.01 posted on Google Play Store. Am right in middle of building the 2.0 version…(VLF) and have not found updated video yet. What are the changes and do they change the existing electronic circuits you posted?

    1. hello! The changes only for next version, you can use the same schematic but new schematic is better and works with all version of the app. for now it is on Russian page, just change language in my web page and you can see it

  25. I built and worked with Smart Hunter. In my situation the detector appears to work well with ‘Rx splitter’ on 100

    Can you give a brief explanation of the settings?
    1 / what does ‘Rx splitter’ mean? What is the effect of adjustment?
    2 / what is the effect of ‘Test value’?
    3 / How does the ‘Ground Balance’ work?

    I’m looking for a 5v amplifier with more power. This is due to a larger coil. Do you have a suggestion?

    What is the exact type of Detech S.E.F. Coil that you use?

    I appreciate your work!
    Thanks for the replies !!!

    1. Hello Rx splitter is the value that divide the signal by the selected number. We need it be cause there are lot of noise so we adjust this value to quit nois. In my case only vorks with 500 or 1000 be cause sensetive amplifier of my smartphone
      Test value for now is nothing, it just for me.
      I working on ground balance, for now i take on the ground balance in the app.
      i use 12″ 10″ DD coil

  26. Hello, thank you also for the information on the RX Splitter! I was confused that you suggested 500 / 1000 and my ‘phone worked the best on 100…

    Do you believe that the present circuit board will still be useful as it is now when you add Discrimination (Possibly as a second add-on circuit)? Or, will a total redesign be more likely?

    I had great problems with the old RX circuit to the smart phone as the signal was too low to pick up (very faint)and the preamp I had was too strong for the graphic on the updated app, so I have just ordered the circuit board to build the proper preamp (my test ‘phone is a Blu R1 HD so that may explain it, Lol!).

    Again, Thank You so much for your work, it is fun trying to keep up!

  27. Sorry, did not see that my first comment posted…it never showed up when I viewed this page. Thank you for pointing out the Russian page! looks like the TX amp is improved. Is it also an improvement over Arduino TX (I suspect yes, much)?

  28. You can explain how many rounds of receiver and transmitter loop and wire size you can tell both the sender and the receiver, email me if possible.

    1. سلام میتونم یه شماره تماس ازتون داشته باشم برای راه اندازی این پروژه فلز یاب

  29. You can explain how many rounds of receiver and transmitter loop and wire size you can tell both the sender and the receiver, email me if possible.

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