I had someone ask me the other day about "dust / smog" detection. They
wanted to automatically close some windows when the outside air quality
was poor (lots of particulates).
My initial thought was a simple IR LED + photo diode pair to sense a
reduction in emission. I then pulled a photo electric smoke alarm apart
to look at the optical chamber. It uses an IR LED and photo transistor,
but set at 90° to each other. The smoke particles cause a reflection as
opposed to beam interference.
A quick look online for commercial sensors only seemed to reveal ones
designed for clean rooms (BIG $$), or actual smoke alarms. Has anyone
been down this path before?
David...
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David Duffy Audio Visual Devices P/L
Unit 8, 10 Hook St, Capalaba 4157 Australia
Ph: +61 7 38235717 Fax: +61 7 38234717
Our Web Site: www.audiovisualdevices.com.au
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