555 metal detector problem in making inductor L1

[Er Sanjit]

hi,
I am making a metal detector for my robot. I decided to make single metal detector, that's why I chose it making with 555 as I don't have time for complex circuits. Now, the problem I am having is that I don't know how to make a inductor suitable for the circuit.




I have used 1microF capacitors instead of 2.2microF.
So, what i had to do to make suitable inductor.


THE MAIN PROBLEM IS THAT I DONT KNOW HOW THIS CIRCUIT WORKS AND I DONT EVEN KNOW HOW TO MAKE INDUCTOR SUITABLE



PLEASE HELP ASAP

THANKS

 

[kam1787]

This should help: https://www.instructables.com/id/Simple-metal-detector/