The famed inventor who created the first practical metal detector in 1881 was Alexander Graham Bell. As President James Garfield lay dying of an assassin's bullet, Bell hurriedly invented a crude metal detector in an unsuccessful attempt to locate the fatal slug. Bell's metal detector was an electromagnetic device. He called it an induction balance device.

With Bell's metal detector, a battery in the top of it activated the transmitter circuit. This circuit was red and passed electricity down through a cable in the handle to the transmitter coil (red) at the bottom. When electricity went through the transmitter coil, it created a magnetic field all around it.

Bell came to the U.S. as a teacher of the deaf, and conceived the idea of "electronic speech" while visiting his hearing-impaired mother in Canada. This led him to invent the microphone and later the "electrical speech machine" (the first telephone).

Bell was born in Edinburgh, Scotland in March 1847. He enrolled in the University of London to study anatomy and physiology, but his college time was cut short when his family moved to Canada in 1870. As a young man and in his adulthood, Bell was well known as an inventor. He not only invented the telephone, but he invented other key devices. He developed the photophone, hydrofoil, HD-4, audiometer, metal detectors, the tetrahedral kite, an electrical bullet probe, etc. Bell died in August 1922 in Beinn Bhreagh.

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