Introduction

The goal of this project is to develop a sensor system to sense, quantitatively characterize and record very small fluctuations (20 Hz - 20 kHz) in the intensity of electromagnetic radiation within the visible frequencies arriving from a remote emissive or reflective source. This signal will then be converted into an audio signal for analysis.

Background

Alexander Graham Bell invented the photophone in 1880 that allowed for the transmission of speech encoded on reflected sunlight. By speaking near a flexible mirror the pressure waves created by sound would vibrate the mirror thus modulating the intensity of the sunlight reflected off the mirror at the frequencies of the voice. These waves were then focused onto a selenium photodetector connected to a telephone receiver reproducing the voical signal produced near the reflector.

Dan Slater, an independent inventor, has recently developed a system that uses this principle of sound waves being encoded onto light to accomplish remote acoustic sensing (RAS). By detecting minute fluctuations at acoustic frequencies of a reflected or emitted source, Slater has demonstrated this system to detect sounds local to reflective sources at over 30 miles. Our project is to develop a system independently of Mr. Slater’s that can accomplish RAS over distance.

Sponsor Information

Prof. David Klumpar | Department of Physics

Director of the MSU Space Science and Engineering Laboratory (SSEL). Sponsor of the Optical Vibration Sensor/Detector project.

Tel: (406) 994-6169
Email: klumpar@physics.montana.edu

Prof. Robert Maher | College of Engineering

Department head of Electrical and Computer Engineering. Advisor of the Optical Vibration Sensor/Detector project.

Office: 610 Cobleigh Hall
Tel: (406) 994-7759
Email: rmaher@ece.montana.edu