I am working on an engineering project and I am looking for ways to have recorded audio play when in close vicinity to ferrous metal. Specifically, I’d want the method to be as compact as possible. I’d assume companies sell sensors that can detect these metals through induction. Also companies probably sell devices that play back audio on cue. What would be the best way to tie these things together? Specifically, what types of sensors are small(MEMS level) and cheap that could detect the metal and transmit a voltage to an audio device(as small as possible, but capable of producing audio of recorded voice clearly and at an audible volume) and use only a minimal amount of power(say the amount a AAA or smaller battery could produce)?
After seeing the first response I’d like to add that the metal will range between 1-5cm from the sensor. I’m not looking for some impossible device.
Let’s also assume that the metal are disc shaped pieces ~.5-1cm thick with a diameter of ~2.5 cm. And you have at least a .5-1 seconds for detection.
Tagged amount, cue, Engineering, engineering project, ferrous metals, induction, Metal, method, play, project, sensors, vicinity, way
