A Simple DIY Metal Detector without using Microcontroller

A metal detector is a device which detects metallic objects. They are commonly used for security purposes on airports, railway stations, malls, etc to prevent entering metal objects like Arms into the premises. 

Designing a metal detector is not that difficult and you can design one simple metal detector circuit without using any microcontroller and by merely using commonly used 555 timer IC. 

This circuit works on 9v DC power supply and uses a copper coil to detect the metal objects. You can find the schematic diagram and detailed explanation of concepts used in this circuit here:

http://circuitdigest.com/electronic-circuits/simple-metal-detector-circuit