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Title: Using lock-in detection to build a barcode scanner
Lock-in detection is a widely used experimental technique in which a weak signal is measured by modulating it at a particular frequency. Then, by detecting an experimental output at that frequency, the desired signal can be isolated from much larger-amplitude noise. Here, we report on the implementation and optimization of a homemade laser barcode scanner based on the lock-in technique. Our setup is comprised of components that are readily available in an undergraduate instructional laboratory. The successful transcription of the barcode into a digital signal was achieved, and this digital signal was collected with a simple computer and processed to reveal the encoded number.  more » « less
Award ID(s):
2011610
PAR ID:
10529280
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publisher / Repository:
American Association of Physics Teachers
Date Published:
Journal Name:
American Journal of Physics
Volume:
91
Issue:
12
ISSN:
0002-9505
Page Range / eLocation ID:
1023 to 1030
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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