Land mines are designed to target enemies during war but many remain even after the fighting stops, causing many casualties to civilian populations. Despite international conventions to ban land mines, more than four-thousand lose their lives every year and countless more are injured.
My team came with all sorts of ideas ranging from using rakes to radio-controlled cars, but I came up with the idea to build a metal detector that could transmit and receive electromagnetic waves which can be altered by metals. At the same time, I wanted it built using simple household appliances. The real inspiration came when I learnt that electromagnetic waves produced by an electrical circuit can be picked by an AM radio.
Given that the design needed to be able to be used by civilians in rural areas, my choice of using a calculator and radio meant a cost effective method would be implemented. I bought a solar-powered calculator which has a larger surface compared to the radio. I thought that if the calculator was solar, it wouldn’t require batteries or electricity to function; it would just convert the light energy into electrical energy. Unfortunately my radio is battery powered. On the bright side, it is an energy-saving radio with an indicator which shows your battery charge. All of this makes this Metal Detector simple, efficient and quite cheap.
I started during the Christmas break while I was back in India and found the metal detector to be very sensitive to other electromagnetic waves such as Wi-Fi and radio waves. Therefore, to make it less sensitive to these ‘fake signals’, I decided to increase the receptor frequency on the radio thereby increasing the pitch of the static on the AM radio. This meant the higher frequency created a high pitch static which is very similar to the static produced when electromagnetic fields are in range. Therefore, when the metal detector comes close enough to any metal, the low-pitch beeps can be differentiated from high pitch waves.
I plan to build a wooden shaft on which the metal detector can be attached so the user won’t have to bend down during the search for metals. I also want to build an electromagnetic shielding to prevent other electromagnetic waves from interrupting the metal detection.
I would like to thank my grand-dad for providing me with the required devices and Mr. McKenna for helping us to think productively, bringing out our creativity.
Ashwin, Year 8