*Open source plugin for WeeWX software.

A WeeWX plugin that gets its AirLink sensor readings either directly from the AirLink sensor or from a airlink-proxy service.

Copyright (C)2020 by John A Kline (john@johnkline.com)

This plugin requires Python 3.7, WeeWX 4 and the wview_extended schema

weewx-airlink requires the wview_extended in WeeWX 4 that contains pm1_0, pm2_5 and pm10_0 columns. With the weewx-airlink extension, Loop records will be populated with pm1_0, pm2_5 and pm10_0 fields that correspond to AirLink's pm_1_last, pm_2p5_last and pm_10_last fields.

In addition to pm1_0, pm2_5 and pm10_0, AQI variables are also available (even though they are not in the database) via WeeWX 4's XTypes. pm2_5_aqi is automatically computed from pm2_5 and can be used in reports ($current.pm2_5_aqi, $day.pm2_5_aqi) and in graphs ([[[[pm2_5_aqi]]]). Also available is is the RGBint value $current.pm2_5_aqi_color (useful for displaying AQI in the appropriate color (e.g., green for AQIs <= 50).

PM2.5 concentrations are corrected with the US EPA correction for PurpleAir sensors. This somewhat presumptious decision was prompted by the observation that the AirLink sensor tracks remarkably well to a like positioned PurpleAir sensor. Take this observation with a grain of salet (sample size == 1).

The pm1_0, pm2_5, pm10_0, 'pm2_5_aqi' and 'pm2_5_aqi_color' fields are available for reporting and graphs, the following additional fields are inserted into loop records (useful for real time updating): pm1_0_1m: PM1 1 minute average pm2_5_1m: PM2.5 1 minute average pm10_0_1m: PM10 1 minute average pm2_5_1m_aqi: PM2.5 1m AQI pm2_5_1m_aqi_color: PM2.5 1m AQI color pm2_5_nowcast: : PM2.5 NowCast pm2_5_nowcast_aqi: PM2.5 NowCast AQI pm2_5_nowcast_aqi_color: PM2.5 NowCast AQI color pm10_0_nowcast: PM10 NowCast

A skin is provided to show a sample report:

If you don't meet the following requirements, do not install this extension.

• WeeWX 4
• Using WeeWX 4's new wview_extended schema.
• Python 3.7 or greater

1. Download the lastest release, weewx-airlink-1.0.1.zip, from the GitHub Repository.

2. Run the following command.

   sudo /home/weewx/bin/wee_extension --install weewx-airlink-1.0.1.zip

   Note: this command assumes weewx is installed in /home/weewx. If it's installed elsewhere, adjust the path of wee_extension accordingly.

3. Edit the AirLink section of weewx.conf (which was created by the install above). In particular, change the hostname in the section labeled Sensor1 to be a name resolvable to the IP address of an AirLink sensor or the IP address of an AirLink sensor. More sensors can be specified. For example, to add a second AirLink sensor, enable the Sensor2 section and specify the hostname. There is no limit to how many sensors can be configured; but the numbering must be consecutive. The order in which sensors are interrogated is low numbers to high. Once a sensor replies, no further sensors are interrogated for the current polling round.

   Note: The port can be specified because this extension also works with the airlink-proxy service. That service typcially uses port 8000.

   [AirLink]
       [[Sensor1]]
           enable = true
           hostname = airlink
           port = 80
           timeout = 2
       [[Sensor2]]
           enable = false
           hostname = airlink2
           port = 80
           timeout = 2
   

4. Restart WeeWX

5. To check for a successful install, wait for a reporting cycle, then navigate in a browser to the WeeWX site and add /airlink to the end of the URL (e.g., http://weewx-machine/weewx/airlink). The PM2.5 and AQI graphs will fill in over time.

Note: Although the examples below show the use of $current, aggregates are also supported (e.g., the high PM2.5 for the week can be presented with $week.pm2_5.max.

To show the PM2.5 reading, use the following:

$current.pm2_5

To show the Air Quality Index:

$current.pm2_5_aqi

To get the RGBINT color of the current Air Quality Index:

#set $color = int($current.pm2_5_aqi_color.raw)
#set $blue  =  $color & 255
#set $green = ($color >> 8) & 255
#set $red   = ($color >> 16) & 255

To show the PM1.0 reading, use the following:

$current.pm1_0

To show the PM10.0 reading, use the following:

$current.pm10_0

weewx-airlink is licensed under the GNU Public License v3.