portable metal detector
The list of components for making metal detectors like this is: 1-NE5551 -1mH coil (
I have reduced the value from 10mH to saving some copper that assembled my own coil because of less inductance => less wire rotation)2 -2.
2uF electrolyte capacitance s1-
10uF electrolyte capacitance 1-47K resistor1 -8R speaker1 -
SPST NO1-pressure button switch
Optional components for 9V battery: 1-green LED1 -
The difficulty of the metal detector is the coil.
I don\'t know if we can find some coils, and the specific value of the mH we need.
So I made my own coil with an empty round pringles bag with a diameter of 7 cm.
Considering the value of 1mH, in order to start the construction of the coil, I just need to simulate the length of the coil and the number of rotations.
For these simulations, I used this empty core inductor calculator: using a wire of 0, MM, I got the result of 121 spins and the length of the coil is 39mm.
I cut the 39mm of a piece, from the empty packaging pringles Pinke for a long time 0, 3mm of the 121 rotating copper, making the coil we can see in the picture.
Calculator means that the value is valid for the value of length> 0,4 * diameter with an accuracy of 1%.
In this case, I made a coil with 1mH ,/-1%.
As I mentioned in the introduction, I used the 555 scheme and made some changes, adding a signal LED and a way to adjust the speaker volume.
In this step, we can see the slight difference between the two schemes in two pictures.
The first assembly of the circuit must be carried out in the breadboard to test whether it is valid and to come to the first conclusion about the detection range, and so on. . .
I don\'t have any pictures of the circuit assembled on the breadboard to share. :(
After determining the full function of the circuit in the circuit board, we can install it in the PCB, or install it in the pre-
Like me, through the board.
The picture shows the equipment that has been installed, in an empty old toothpaste box, the circuit heats up
Stuck inside, hot coil-
Glued to the top of it, the lid of the potentiometer opens.
Now, I have my own portable metal detector!
All I need to do is press the button to start the search. . . :)