The MO 2000 optical microphone (photo, p. 28D-4) utilizes a new type of transducer that processes acoustic signals on the basis of variations in light intensity. In the optical microphone, light from an LED is directed onto a reflective diaphragm via a transmitter fiber-optic cable. The diaphragm reflects part of the light into a receiver fiber-optic cable. If the diaphragm is moved by sound signals, the reflected light beam is deflected, with the result that more or less light is coupled into the receiver fiber-optic cable, and then converted into electrical signals. The current- and metal-free design allows the microphone to be uninfluenced by magnetic fields. — Sennheiser Electronic Corp., Old Lyme, Conn.
This microphone measures sound based on light variations
| By Chemical Engineering