Generally, metal detectors can detect metals like nickel, iron, aluminium, bronze, tin, lead, copper, etc. They are also able to recognize coins, jewelry and other precious metal objects. The process through which the detector can distinguish between different kinds of metals is called discrimination.
Yes, a metal detector can help you to find your keys. Almost all the metal detectors give out signals which can detect the keys effectively. However, be sure of the locations where you might find the keys as you may end up detecting all other metal items.
Metal detectors use electromagnetic signals to detect the metal items in a given area. These signals are termed as metal detector sensors. Mostly, the proximity sensor is utilized in the working principle of a metal detector.
The hand-held metal detectors are quite safe for the people with pacemakers. Generally, the people with a pacemaker can safely travel in airlines as these devices do not affect the airline detectors. However, in rare cases, they may set off the airport metal detectors.