Metal detector from remote control

Metal detector from remote control

Anyone can assemble a very simple metal detector with their own hands without understanding electronics at all. With it you can search for metal objects both in the ground and in the wall. The design consists of only three items, which almost everyone probably has lying around in a drawer without use.

Will need


  • Unnecessary remote control for any device.
  • AM/FM radio.
  • Wire for making coils with a diameter of 0.4-0.2 mm.

Metal detector from remote control

Making a metal detector from a remote control and a radio receiver


The first step is to make a coil. Here you need to understand that all sizes and numbers of turns are selected exclusively experimentally, and the example below is not ideal.
Take a 0.35 mm wire and wind a coil with a diameter of 10 cm. The number of turns is 50. To prevent it from unwinding, secure it with electrical tape or nylon ties.
Metal detector from remote control

Let's sort out the bullets. We clean the enameled leads and solder them parallel to the infrared LED.
Metal detector from remote control

Metal detector from remote control

Next, we assemble the remote control. Be sure to put good batteries in it. Turn on the radio and set it to the “AM” range (medium waves).
Metal detector from remote control

Press any button on the remote control.
Metal detector from remote control

We place the receiver near the remote control, and the coil a little further away.
Metal detector from remote control

Repeated sounds should be heard in the receiver, which should disappear when the button is released. By rotating the receiver's tuning wheel, we achieve minimal audibility of these vibrations.
We bring a metal object to the coil at some distance. The sound should be amplified.
Metal detector from remote control

That's all. The sensitivity, when adjusted correctly, is quite acceptable: it is enough to detect steel dowels or reinforcement in the wall.
This metal detector operates on the principle of parasitic harmonics. As soon as the metal is brought close to the coil, its inductance changes, and therefore the frequency of the signal and all harmonics. What the radio receiver actually picks up.
To increase sensitivity, you need to experiment with the coil by changing its size and number of turns. And with a radio receiver, changing bands and making precise searches by adjusting.

Watch the video


See the video for an example of work:
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Comments (4)
  1. Guest Yuri
    #1 Guest Yuri Guests 30 August 2019 16:48
    5
    AM is not a range, but amplitude modulation.The medium wave range is MW (medium waves).
  2. Alexander Fedorovich
    #2 Alexander Fedorovich Guests 24 October 2019 14:23
    3
    When the iron is brought in, the inductance and its parameters change, and the frequency is set by the remote control and it does not change. Something is wrong in the description.
    1. Well
      #3 Well Guests 24 October 2019 14:59
      4
      It's like that! The frequency is set by the low-frequency remote control, and the circuit generates a damped frequency at its resonance.
      In a microwave oven, a constant frequency of 50 Hz is also supplied to the magnetron....
  3. Minsk
    #4 Minsk Guests 16 March 2020 17:11
    4
    The receiver should be kept closer to the coil, and not to the remote control. Is not it?