Metaldetectors have been in existence for many years. In their former years, theywere develope as a way to detect explosives. However, the first Metal Detector was inventedby Alexander Graham bell in1881. Since then, the concept of how they work hasremained largely unchanged. They work on the two concepts of electricity andmagnetism. Refinement of this technology over the years has led to thedevelopment of the different types of metal detector currently in existence. There aresome types of metal detector: VLF detector, pulse induction and beat frequencyoscillation.