On 8/16/2018 3:44 PM, Jeff Liebermann wrote:
On Wed, 15 Aug 2018 18:10:56 -0700, mike wrote:

The Nikken (what passes for a manual) gives no
clue as to particle size.
The Nikken website has no info.
This is all I found on the web
http://802.11junk.com/jeffl/Nikken%2...ity%20Monitor/

Oh-oh. I've been discovered by Google.

I'd rather not take it apart if it's working as designed.

You're no fun. Learn by destroying which means tear it apart until
you understand how it works.

Based on your experience, I think I know how it works.
The question is not how, but what is this particular model
Nikken 1394 actually measuring
in terms of particle dimensions.
My symptoms suggest that it does a poor job on forest fire smoke
from 200 miles away.
Is your experience different?
Is mine broke?
Or just not suited for very small particles?

Anybody got any relevant info?

Page 4 of the manual proclaims:
Level Color Particles/liter
of air
1 blue 500
2 yellow 1000
3 yellow 2000
4 yellow 3000
5 red 5000
6 red 5000+

https://en.wikipedia.org/wiki/Nephelometer
Link to a previous discusion about a light scattering nephelometer:
https://groups.google.com/d/msg/sci.electronics.design/CKc57kEaijA/yZR8lgIa5soJ
See:
https://groups.google.com/d/msg/sci.electronics.design/CKc57kEaijA/xdV8p7aBM3MJ
for a list of links to various similar devices by Sharp and Sinyei
along with explanations as to how they operate.

The sensor has a big CAM-003 inscribed on its case, but no manufactory
and hints as to who made it. I can't find anything useful with
Google. General image search for nephelometer:
https://www.google.com/search?tbm=isch&q=nephelometer
which finds some interesting stuff.

"Sizes of airborne particles as dust, pollen bacteria, virus..."
https://www.engineeringtoolbox.com/particle-sizes-d_934.html
Burning Wood 0.2 - 3.0 microns

25 dust sensors on Digikey:
https://www.digikey.com/products/en/sensors-transducers/dust-sensors/509

"Wildland fire ash: Production, composition and eco-hydro-geomorphic
effects"
http://cesonoma.ucanr.edu/files/272305.pdf



Thanks for the links. I'm sure that's all good stuff, but does it
answer the question, "what can I expect from the Nikken?"
Should I take it apart in anticipation that cleaning it will help
measure small particles? If I can't, I should just not try to use
it for that.
The Dylos seems to read closer to what the Air Quality websites
publish. I built a battery pack for it, so now it's portable.