Author Topic: PurpleAir PA-II  (Read 616 times)

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Offline waysta

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PurpleAir PA-II
« on: October 17, 2017, 12:09:39 PM »
After watching sensors on the west coast respond to the smoke from the brush fires, I decided to buy a PurpleAir PA-II.

One of my interests is to understand AQI numbers from outdoor burning.  For example, what is the range from a smell of burning smoke to higher AQI numbers of possible concern for health risks?

The unit came nicely packed.  Installation was easy with a single drywall screw installing the sensor to the side of the house under the eves to mounting the outdoor power supply to the wall below the unit.  In both cases I used my own screws, longer than those supplied.  Fortunately, I have already have an outdoor 120V outlet with a weather cover in range (15 feet) and plugged the sensor power supply in there.

The unit powered up fine and connected in minutes following the WiFi procedure.  The web GUI shows RSSI (received signal strength at the unit) and even plots a graph of RSSI with time.  Ironically, everything installed fine, the first time with no problems, so I may never need that RSSI feature, other than to tweek WiFi router antenna positions to see any sig. strength changes at the sensor, just for interest.

My unit is graphing fine on the PurpleAir map.  Not sure how to log data, or if that is possible.  For now, its not a concern.  Standard concerns with reporting through a 3rd party server apply, hopefully that will not be a problem.

The hardware seems well built and solid.  In the "spirit" of much higher cost laser particle counters (and it is a dual sensor - self comparing unit), the cost may not be that high.  Although it is on the higher edge for a home hobby installation, especially considering similar stand alone (not WiFi) lower priced units from CN flooding the market. 

On the other hand, the PurpleAir Web map is very good, and each station graphs significant sensor detail there, both particle count data and sensor hardware health data.

Overall, my initial impressions are very positive.

https://www.purpleair.com/map?&zoom=8&lat=42.851057995157156&lng=-75.7759850692749&clustersize=30&orderby=L&latr=4.067323068869335&lngr=8.272705078125

click on each sensor oval to see the detail for that station, (some selections (e.g. particles) have two rows of tabs, one over the other) to select the various data pages.
« Last Edit: October 17, 2017, 12:27:56 PM by waysta »

Offline cjohlandt

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Re: PurpleAir PA-II
« Reply #1 on: October 17, 2017, 08:03:59 PM »
I've had my PA-II up for several months now and it just works.  No problems whatsoever.  Brian added support for PurpleAir in Weather Display a couple of months ago, making it easy to pull your AQI data and use on your website.

-Chris

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Online Eno

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Re: PurpleAir PA-II
« Reply #2 on: December 19, 2017, 11:02:14 AM »
I own a PA-II-SD and look at their map often, but the website isn't developed well for a phone, except last week a Purple Air app appeared on my Samsung S8 and it appears to be optimized for a mobile device.  Just weird that it appeared on the homescreen and I never did anything to put it there.

Online Eno

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Re: PurpleAir PA-II / Classic early adopter tale
« Reply #3 on: December 26, 2017, 09:43:25 PM »
After about 40 days of working perfectly, the PurpleAir PA-II-SD I installed on November 19 will not stay online. I have been unplugging the power, waiting about 15-30 minutes (shorter time doesn't seem to work), restoring power, then it will appear on the map, but disappear from the map again anywhere from within an hour to 12 hours.  Been up and down a ladder about a dozen times in the last four days.

I've changed some router settings; tried different channels, specified 802.11 n only mode, and got the RSSI down from -70 to -74 dBm down to -59 to -64 dBm.  I don't think it's on my end.  I think it's something in the device itself or something in their network.  The number of offline devices fluctuated from about 49 down to 17 just today, currently at 42.

  :-& :-& :-&

Offline Skywatch

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Re: PurpleAir PA-II
« Reply #4 on: December 28, 2017, 08:17:36 PM »
I've had my PAII running for about 4 weeks. My uptime fluctuates most likely from being on the other side of the house from the router.

At first during the initial setup it was sending then dropped out after I unplugged the sensor to install it and it dropped the house's WiFi code and after a day of trying to figure it out I had to redo the setup.

I've actually gotten intrigued by the information.  Some days depending on the wind direction I can watch other stations in the area fluctuate then see my numbers change in sequence. It's also interesting to see my AQI high up over 50 then with the passing of a cold front it drop to single digits. Someday I'm going to figure out the Weather Display setup.
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