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Cheap particle counter for clean bench. Is it good enough?

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masterpj55:
it looks great! i bought the particle laser sensor listed above through amazon (should arrive in 2 days) which i can interface with a pc.
The only thing I struggle to find out is a good set of reference how particle size corrilates to cleanlyness.. say in a clean box of clean bench what is a good number (to for example know if your filters need changing).

Say for laser optical work or some rough semiconductor or open hard drive work as reference!

I noticed your display also shows PM1.0   this is something that isn't to be found on the other laser particle counter (says PM10 and 2.5). is this an advantage of the sensor you bought?

DrG:

--- Quote from: masterpj55 on March 16, 2021, 12:50:49 am ---it looks great! i bought the particle laser sensor listed above through amazon (should arrive in 2 days) which i can interface with a pc.
The only thing I struggle to find out is a good set of reference how particle size corrilates to cleanlyness.. say in a clean box of clean bench what is a good number (to for example know if your filters need changing).

Say for laser optical work or some rough semiconductor or open hard drive work as reference!

I noticed your display also shows PM1.0   this is something that isn't to be found on the other laser particle counter (says PM10 and 2.5). is this an advantage of the sensor you bought?

--- End quote ---

Thanks, but I was aiming at indoor air quality. For example, I am alerting based on USEPA 24h limits.

--- Code: ---// Levels for alarm based on EPA 24h limits
unsigned long PM2_5alarm = 35.0;
unsigned long PM10_0alarm = 150.0;

--- End code ---

I don't know squat about clean rooms and the like but a quick search looks like there are all sorts of "standards" e.g., https://www.americancleanrooms.com/cleanroom-classifications/. I have no idea how suitable your device will be for such purposes (again the validation issue previously mentioned).

Edited to add: as for the 1.0 um - well, yeah, I like that, but it may be included in other sensors. You have to look at the datasheet. For example, it should say something about "smallest particle size detected" or something similar. It is then "assumed" that a measure reporting, for example, <2.5 um is including the smallest size particles the sensor can measure.

BUT, and I know I keep coming back to this, I have no way of validating or calibrating these sensors. I am basically basing whatever utility mine has (and it is more experimental interest than anything very important) on the data sheet and gross empirical observation (like the measures in response to some smoke that I mentioned earlier).

These are very important questions and I would be very concerned to find the answers, if the application is also very important - you know what I mean?

David Hess:

--- Quote from: masterpj55 on March 14, 2021, 10:11:00 pm ---What niche do these particle counters fill? Would either of these particle counters be able to suffice for measuring the particle count in a clean bench (laminar flood hood) to see if it's still adequate and the filters are in need of replacement or not?
--- End quote ---

I would use them to verify that a laminar flow bench is operating correctly.

GodIsRealUnless DefinedInt:
I've seen laser light scattering sensors on Ali for about $14 Inc shipping. Usually these styles of units bin data into size categories <1um, to 10um and in between. How much worth they are depends on your filters and their specification. Usually HEPAs run around 0.3um. So it would be pushing it with a unit like I've seen. Question I would have is what does <1um mean, where does the particle size limit get reached for deflection against a sensor. These deflection sensor based units also have a shelf life so consider them consumables. I would use them for sure in a home setting or in a garage workshop. They'll definitely spike when you fire up a soldering iron and vaporize solder/Flux. But for a commercial operation you'd want something certified as to performance specifications.

Edit: sensor only intended to hook up over serial to get the data.

Data is in per deciliter or cubic meter so with most scientific gear you have to convert yourself to local units.

masterpj55:

--- Quote from: David Hess on March 16, 2021, 04:47:48 pm ---
--- Quote from: masterpj55 on March 14, 2021, 10:11:00 pm ---What niche do these particle counters fill? Would either of these particle counters be able to suffice for measuring the particle count in a clean bench (laminar flood hood) to see if it's still adequate and the filters are in need of replacement or not?
--- End quote ---

I would use them to verify that a laminar flow bench is operating correctly.

--- End quote ---

Exactly what I bought mine for ! :)
However is the SDS011 sufficient for that you think?

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