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

DiscoverCircuits.com, has 45,000+ electronic circuits, cross-referenced into 500+ categories.
We have searched the web to help you find quick solutions & design ideas.

Got Designs?
Please eMail
if you want me to link to and/or post your original design
NOTE:  We make every effort to link to original material posted by the designer. 
Please contact us if our link is not to your site!  Thanks.

DiscoverCircuits.com -- Hobby Corner
Last Updated on: Tuesday, June 01, 2021 03:06 PM

Hobby Circuits List

The contents & graphics of Discovercircuits.com are copyright protected.
LINK to Dave's circuit, but DO NOT COPY any files to your WEB SITE server

More  Alarm Circuits 
Bistable Multivibrator or Flip/Flop Circuits   
Light Detectors or Optical Sensors

It's Time to Dust Indicator
Also see Circuit Solutions

I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough. I have not yet built and tested this circuit completely but in concept it should work. The circuit draws very low current from a +3v battery and could be housed in a package similar to a small ashtray. The assembly might be placed in a suitable out of the way area to collect dust. It would alert a maid when it was time to dust the room. The circuit detects dust with an infrared LED that is pulsed so its light shines onto a smooth flat plate. Any dust settling onto the surface is detected by a phototransistor, mounted at a 90 degree angle from the LED. When the dust reaches a particular level, sufficient light is reflected into the phototransistor to change the logic state of the circuit to an alarm condition. The alarm output could be connected to a beeper, a flashing LED or to one of the LED flashing circuits in this hobby circuit section.

Click on Circuit Below to view PDF of Schematic

Battery Powered Dust Monitor designed

 by Dave Johnson, P.E. (July 6, 2000)

More  Alarm Circuits 
Bistable Multivibrator or Flip/Flop Circuits   
Light Detectors or Optical Sensors

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

HOME Schematics Index Hobby Corner Dave's Circuits Contact Info
Imagineering Ezine Dave Johnson & Associates Faraday Touch Switches

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

Copyright  January, 1998 - June, 2021     David A. Johnson  All Rights reserved. 
 Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.