PMSA003I 0 values

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Sky737
 
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PMSA003I 0 values

Post by Sky737 »

Hi, I purchased a PMSA003I Air Quality module but upon powering it on on and testing the default code the module slowly leveling its values at 0. The air outside my home definitely has higher than 0 pm2.5 concentrations. It's also worth noting that the module does read values if it is exposed to smoke. It is only reading these 0's in ambient air inside and outside. I was wondering if anyone had seen this problem before or if it is a defective product. Thanks!
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adafruit_support_carter
 
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Re: PMSA003I 0 values

Post by adafruit_support_carter »

Not sure, since it seems to be responding in general. Does the response test with smoke seem generally OK?

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Sky737
 
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Re: PMSA003I 0 values

Post by Sky737 »

Yes it does work with smoke just not in ambient air (which is what I need)

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rmvsintheta
 
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Re: PMSA003I 0 values

Post by rmvsintheta »

Hey! I have two of these units, and I have noticed that when I start up the units, the readings do tend to start high then level off as the fan blows out the settled dust (down to zero if the air is particularly good). It usually settles within a minute or two.

It's very possible the the indoor/outdoor air is better than you expect (A couple days ago the value dropped to zero in the city I live, when it's usually 5-15 . (Both of my sensors independently read this value). Also, I've noticed a building that I often work in has much better air filtration than I expected, and reads 0 at all times inside. The same unit taken to an indoor climbing gym consistently reads ~20-30 (as expected from all the chalk particles).

I suggest (if you haven't already) to take the unit to other places (if possible), and see if the output values are consistent at those locations. You might find interesting results in the process!

But, if you really think you have a problem, there are a couple things that I've noticed that might be issues (I'm still testing/working things out for myself; I've had one unit for a bit over a month, and the other for a week or two)

1. The units seem sensitive to power issues: I've gotten very unpredictable weird spikes in PM2.5 levels with voltage instability. I have a bunch of I2C devices daisy chained with STEMMA QT connectors, and I ended up having to run independent lines for Vin and GND directly from my lipo battery to the PMSA unit to ensure stable power.

2. If you exposed it a lot of dirty/oily air, you might try blowing out the chamber with one of those hand squeeze blowers (i probably wouldn't use canned air- too high pressure/cold). I tried disassembling one of mine to clean it, but I don't really recommend it- it's a real pain, and I don't think it helped much if at all.

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Sky737
 
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Re: PMSA003I 0 values

Post by Sky737 »

This was really helpful I will definitely try all this out and keep it updated on the forum

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adafruit_support_carter
 
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Re: PMSA003I 0 values

Post by adafruit_support_carter »

Yep, agree. Those are all great suggestions. Thanks @rmvsintheta for the input.

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