Undergraduate Electronics Projects Based on the Design of an Optical Wireless Audio Transmission System

The two projects presented in this paper can be used either as two separate assignments in two different semesters or as a final assignment for undergraduate students of electrical engineering. They have two main objectives: first, to teach basic electronic circuit design concepts and, second, to motivate the students to learn more about analog circuit design. The two projects are: 1) the design of an audio power amplifier, and 2) the design of an amplitude-modulated optical link with a pulsed light-emitting diode (LED) at the emitter and a photodiode and a transimpedance amplifier at the receiver. An audio signal is used to modulate the oscillator that drives the LED, and the receiver demodulates this signal to produce an audio signal (music, for example) that can be sent to a loudspeaker. The intent of this optical communication system was to allow students to design and build various electronic circuits that have an overall objective and a clear practical application. Students are motivated by using this system to transmit, receive, and listen to their own music.