Electronic Circuits and electronic circuits, electronic schematics plus an extensive resource for hobbyists, inventors and engineers

DiscoverCircuits.com, has 30,000+ electronic circuits, cross-referenced
into 500+ categories.    We have searched the web to help you find quick design ideas.
We make every effort to link to material posted by the designer. 
Please let us if you would like us to link to or post your design.

HOME Schematics Discover Forum Hobby Corner Dave's Circuits Electronic Resources Book Corner Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches
 

DiscoverCircuits.com -- Hobby Corner
Last Updated on: Tuesday, November 29, 2011 08:14 PM

Hobby Circuits' Category List

The contents & graphics of Discovercircuits.com are copyright protected.
LINKING to Dave's circuits is permitted but DO NOT COPY any files to your WEB SITE server



 

Reflected Infrared Light Switch
designed by David Johnson, P.E.

This hobby circuit has been used in some museum displays and exhibits when the electronics needed to trigger an audio/visual presentation is behind a plastic or glass panel.  A finger pressed against the glass, over a designated area triggers the switch. 

Infrared light reflected off a finger is used to activate this switch circuit. Drawing only 30uA from a 3v supply, this electronic circuit will detect a human finger with a range of about 1 inch.  The sensor uses an inexpensive infrared LED and a matching photo diode.  The circuit is immune to ambient light.

Click on Drawing Below to view PDF version of Schematic

Circuit Reflected Infrared Light Switch Circuit


Hobby Circuits' Category List
eMail David A. Johnson, P.E. about this circuit

HOME Schematics Discover Forum Hobby Corner Dave's Circuits Electronic Resources Book Corner Contact Info
 Linking is welcomed but COPYING any content or graphics to your web site is expressly prohibited.

 About Us   |  Advertise on DiscoverCircuits.com   |   Report Broken Links  |    Link to DiscoverCircuits.com  |    Privacy Policy