I’m Varnit Goswami with username electrronix from Uttarakhand, India. Here is about my first electronic project “metal detector” and I made this project in class 12th.
A metal detector is an electronic instrument which detects the presence of metal nearby. Metal detectors are useful for finding metal inclusions hidden within objects, or metal objects buried underground. The simplest form of a metal detector consists of an oscillator producing an alternating current that passes through a coil producing an alternating magnetic field. If a piece of electrically conductive metal is close to the coil, eddy currents will be induced in the metal, and this produces a magnetic field of its own. If another coil is used to measure the magnetic field, the change in the magnetic field due to the metallic object can be detected.
So, in my project, I have used a magnetic coil which generates a pulse(signal) with time using IC 555(called timer IC). These signals are strike back from a metallic object and produce an eddy current in it, which creates a variation in pulse. These variations are observed by buzzer which makes a different sound when a metallic object is near.
- IC 555 with IC holder
- 47 Kohm resistor
- Two 2u2 F capacitor
- Zero PCB
- 9V battery
- push button
- 32 gauge (0.2mm in dia) insulated copper wire about 100m
- Electric tape
- Instead of a buzzer, you can use 10 μF capacitor and speaker (8 ohm impendence)
- Breadboard wire
- Soldering rod and soldering wire
- circular object
- The most difficult part is making coil. In great help was web calculators for air coils. A coil will be made by using a circular object.
- Before soldering, you must clean up both ends of the coil. You can do that with the help of sandpaper.
- Then, the whole circuit will make on a zero PCB and solder the components.
- Check the sorting using a multimeter.
- Finally, connect a power supply with the circuit and tested by pressing a push button near a metallic object.
- There is a Video link.
This detector is really very simple one. But I must make a note that it is not meant for serious work. But it is a simple and fun project for beginners. I must say I had a great time making it and using it!!