Author Topic: Davis Airlink Professional Air Quality Sensor PM 1, 2.5 & 10 (Read 15361 times)

jasonmfarrow · « **Reply #75 on:** October 06, 2020, 08:56:24 AM »

Interesting chart - what's the source website as I'd like to compare my own in the same way.
I also like your template and the AQI in particular - https://warehamwx.co.uk/air_quality.php. Are you able to share the source code for this page?

mcrossley · « **Reply #76 on:** October 06, 2020, 09:05:30 AM »

Quote from: ConligWX on September 24, 2020, 04:55:36 PM

looks like we have about 15 or so in the UK now.

Looks like its up to 21 now

Mapantz · « **Reply #77 on:** October 06, 2020, 01:10:57 PM »

Quote from: jasonmfarrow on October 06, 2020, 08:56:24 AM

Interesting chart - what's the source website as I'd like to compare my own in the same way.
I also like your template and the AQI in particular - https://warehamwx.co.uk/air_quality.php. Are you able to share the source code for this page?

Drop beteljuice a message. He should be able to sort you out.

josecmorales · « **Reply #78 on:** October 16, 2020, 09:06:23 PM »

Well, im waiting for mine!

Is this airlink send data to another weather system?

hmderek · « **Reply #79 on:** October 17, 2020, 04:16:17 AM »

So, when using the local API on the airlink, I notice that the field 'last_report_time' updates on each call. It even seems like it updates every second, or at least every 2 or 3 seconds. I also notice that the 'pm_x_last' field, which represents the last reading made by the Airlink, changes slightly on most calls.

The question, how often does the Airlink do a reading that you would potentially want to retrieve? I currently have the readout interval at 15 seconds. I don't think I would want to go much lower in any case, but still interesting question.

wrybread · « **Reply #80 on:** October 17, 2020, 04:33:19 AM »

I made a Python script to test this and found that it updates its readings once a minute. It updates it's averaged out values more often that that though, but I wasn't concerned with those so I didn't try to figure out how often.

Here's the script in case anyone wants to confirm:

Code: [Select]

#!/usr/bin/python

'''

This tests the update frequency of the Airlink. It shows the seconds since change and keeps
track of the fastest responses.

Conclusion: For pm_2p5, it updates once a minute

'''

import aqi # pip install python-aqi
import requests
import time

# IP of the AirLink
ip = "10.10.10.51"

previous_pm_2p5=None
last_update=None
shortest_update_time=99999

print ("Querying the Airlink at %s once a second..." % ip)

while True:
    
    try:
        response = requests.get("http://%s/v1/current_conditions" % ip)
        data = response.json()
        conditions = data["data"]["conditions"][0]

        pm_2p5=conditions["pm_2p5"]
        
        if previous_pm_2p5 and pm_2p5 != previous_pm_2p5:
            if last_update: 
                p = round(time.time() - last_update)
                if p < shortest_update_time: shortest_update_time=p
                print "Data changed to %s after %s seconds. Shortest update time is now %s" % (pm_2p5, p, shortest_update_time)
                
            last_update=time.time()
        previous_pm_2p5=pm_2p5


    except Exception as e:
        print ("Error processing: %s" % e)
        time.sleep(1)
        continue



    time.sleep(1)

hmderek · « **Reply #81 on:** October 17, 2020, 04:40:01 AM »

Quote from: wrybread on October 17, 2020, 04:33:19 AM

Conclusion: For pm_2p5, it updates once a minute

I might be better to target those values, rather than the 'x_last' fields, since they seem to update so fast you'd be missing a lot of data in the mean time unless you'd persist it every 2 or 3 seconds.

wrybread · « **Reply #82 on:** October 17, 2020, 05:03:43 AM »

not sure I understand, but I wasn't targeting the x_last fields, I was retrieving the pm_2p5 value from the AirLink.

My test scripts requests pm_2p5 twice a second and records when it changes. It never changes more than once a minute.

I do use some variables with "last" in their names internally in my script to keep track of previous readings, but those aren't the AirLink variables.

Edit: I just edited my script to change it's internal variable names to avoid confusion with the Airlink variable names.

hmderek · « **Reply #83 on:** October 17, 2020, 05:58:41 AM »

Quote from: wrybread on October 17, 2020, 05:03:43 AM

not sure I understand, but I wasn't targeting the x_last fields, I was retrieving the pm_2p5 value from the AirLink.

I was just referring to my current readout setup, where I query the Airlink every 15 seconds and retrieve all x_last fields. It probably makes more sense to do what your script does, read the 1-minute average.

wrybread · « **Reply #84 on:** October 17, 2020, 11:44:44 AM »

Aha, I didn't realize that was a 1 minute average. I just had it poll pm_2p5_last with a .5 second delay between queries and it updates once a second.

hmderek · « **Reply #85 on:** October 17, 2020, 01:01:03 PM »

I find it a tough call to decide what data to work with. It seems that the readings pretty much update every second and also change at that speed. That is too frequent to readouts of all the updates. If you decide to pick the 1 minute averages, you get a representation of all readings, but you end up with a summary rather than a real time readout. Additionally, the temperature and humidity are always real time, so they don't strictly line up with the pm data being saved. Though that may be splitting hairs, I prefer to have real time readings as to work with as raw data. Does anyone have thoughts one the matter? What are conventions as to the proper way of reading this type of data?

hmderek · « **Reply #86 on:** October 18, 2020, 06:17:20 AM »

Oof, can't say the AirLink readings are boring. Values going much higher than I expected. We live in a (relatively) rural area. But there is a big incinerator about 7 kilometers to the South West. Can't help but notice that when the values started dropping this morning, winds were also changing from SW to W. Way too early to say anything, but I'm definitely going to have fun making sense of the readings in the future!

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wrybread · « **Reply #87 on:** October 18, 2020, 12:43:15 PM »

Very nice chart. What are you using to build it? Or does that come with the "pro" subscription?

Agreed about the winds, I'm right on the ocean in northern california, with fires nearby. When the winds shift the aqi changes dramatically. I really need to figure out how to add wind speed and direction to my chart, which is here:

https://lawsonslanding.com/webcam.html

hmderek · « **Reply #88 on:** October 18, 2020, 01:51:55 PM »

Quote from: wrybread on October 18, 2020, 12:43:15 PM

Very nice chart. What are you using to build it? Or does that come with the "pro" subscription?

Agreed about the winds, I'm right on the ocean in northern california, with fires nearby. When the winds shift the aqi changes dramatically. I really need to figure out how to add wind speed and direction to my chart, which is here:

https://lawsonslanding.com/webcam.html

It's a custom page, built using Chartjs.

Side note, nice webcam feed.

wrybread · « **Reply #89 on:** October 18, 2020, 01:55:39 PM »

Awesome! Well done.

And yeah it's a beautiful day out here today, almost feels like california, ha. Which is rare for the northern california coast.

hmderek · « **Reply #90 on:** October 19, 2020, 10:06:07 AM »

Quote from: wrybread on October 18, 2020, 01:55:39 PM

Awesome! Well done.

And yeah it's a beautiful day out here today, almost feels like california, ha. Which is rare for the northern california coast.

I added the PM values to the dashboard of my website. https://meteodrenthe.nl

Found that the yearly average for my location is around 15 µg/m³. Haven't yet found any maps that are useful to compare my values with. Is there a map with good coverage (for NW Europe) out there?

srpawski · « **Reply #91 on:** October 23, 2020, 05:09:45 PM »

I’m still waiting for a working unit. I received mine last Friday from Scaled and it doesn’t work. It powers and connects to the Internet fine, but will not pull data. Davis confirms that if I don’t hear a fan running that it is bad. They are going to send me a replacement unit directly. They won’t, however, foot for return shipping of the DOA unit I received. Scaled also does not appear to want to assist with covering it, which, frankly, I am a bit taken back and not happy with.

wrybread · « **Reply #92 on:** October 23, 2020, 05:11:20 PM »

Strange, I don't hear a fan running in mine, and it's working... Assuming you're talking about an AirLink.

srpawski · « **Reply #93 on:** October 23, 2020, 05:14:41 PM »

Yes. There is a tiny fan that is supposed to run when it is operating. That is what Davis’ tech support said. He said if its not pulling data and can’t hear a fan it’s likely defective. I know it’s connected to my wifi fine and I deleted it and set it up twice and have done multiple checks with the WiFi in the WeatherLink app and it doesn’t display data but is connected to the Internet.

archae86 · « **Reply #94 on:** October 24, 2020, 10:46:13 AM »

My Airlink is two days in operation at my house. I had not noticed the fan, but after reading these posts I held it right up to my ear in a quiet place and did hear it.

wrybread · « **Reply #95 on:** October 24, 2020, 11:37:10 AM »

Aha, me too, hadn't noticed the fan previously either.

joder · « **Reply #96 on:** November 08, 2020, 04:16:41 PM »

What are folks using for the power supply for outdoors use. The reason I ask is that I have a water resistant cover, however, the plug sticks out too much. I almost need a smaller AC to USB brick at a right angle for it to fit properly.

Wondering if anyone has any good ideas before I reach out to Davis. I'll have to post some pics soon.

srpawski · « **Reply #97 on:** November 08, 2020, 04:19:16 PM »

https://www.amazon.com/gp/product/B07JHZXCQD/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Works perfectly.

Mapantz · « **Reply #98 on:** November 08, 2020, 04:50:32 PM »

Quote from: joder on November 08, 2020, 04:16:41 PM

What are folks using for the power supply for outdoors use. The reason I ask is that I have a water resistant cover, however, the plug sticks out too much. I almost need a smaller AC to USB brick at a right angle for it to fit properly.

Wondering if anyone has any good ideas before I reach out to Davis. I'll have to post some pics soon.

Your best bet is to buy a 5V DC extension cable - available up to 20m. Either put the join of the AirLink cable indoors, or route it through a small - cheap junction box.

oceans311 · « **Reply #99 on:** November 09, 2020, 10:23:22 AM »

So all of my Airlink values show up on the Weather Link website just fine, however when I set everything up in Cumulus Mx I get nothing, has anyone else had difficulty or have some advice to get me running?

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Author Topic: Davis Airlink Professional Air Quality Sensor PM 1, 2.5 & 10 (Read 15361 times)