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How can the metal detector app work? I'm drawing a blank. Does anyone have any theories?

• RK 17y ago
  The internal magnetometer can measure local magnetic field changes due to ferrous metals.
  • tocomment 17y ago
    He says it works on non ferrous metals too. That's what really baffles me.
    • RK 17y ago
      Well, most things will have some non-zero magnetic susceptibility that will affect an ambient magnetic field. Ferromagnetic materials will have a larger effect. I just loaded "Metal Detector" on my Nexus One and played around with it. It seemed to only detect ferrous metals. For example it picked small steel tools fine, but couldn't sense an entire plastic bag full of (US) coins or aluminum objects.
• Groxx 17y ago
  Maybe by bouncing radio waves, similar to this? http://books.google.com/books?id=91B7QvCX_iAC&lpg=PP1&ots=1Sx87T2X1M&dq=sneaky%20uses%20calculator&pg=PA20#v=onepage&q=sneaky%20uses%20calculator&f=false http://books.google.com/books?id=91B7QvCX_iAC&lpg=PP1&#3... It's not the same thing by any means, but I'd imagine you could bounce the cell signal off something, and capture the echo, or "listen" to its interference of surrounding background noise. (for non-clickers: Sneakier Uses for Everyday Things: calculator + radio = metal detector)
• cullenking 17y ago
  My guess is the electronic compass sensor is precise enough that passing by a ferrous metal will change the reading for a moment. If you have a weird 'spike' in the sensor reading it would be easy to see, rather than the gradual change you'd get from a directional change.