Donald Had a Serious Case of Red Eye

Donald liked to wow people with his PowerPoint presentations. So he developed an easy circuit to modulate an audio signal (CD player) and transmit it over a beam of light (using a laser pointer). The receiver is a simple solar cell with a pre-amp transistor circuit connected to the "line-in" of an audio amplifier. The amplitude-modulated beam of light from the laser pointer produces a varying voltage signal that tracks the audio signal. For added gain, Donald also threw in a pre-amp circuit.

For Donald Marzewski's complete instructions on how to build your own inexpensive laser modulator,

click here

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