[RELEASE] PurpleAir AQI monitoring driver

⚙️ Custom Apps and Drivers
26

Hi @pfmiller, it looks like data calls aren't working due to the API changes PurpleAir did earlier this week. Will you be updating the driver?
For now, a quick fix was to switch to the legacy API by changing the url from "api.purpleair.com" to "rollback.api.purpleair.com", which works again. Not sure how long they will be supporting this though.
Thanks!

1 Like
27

@pfmiller I noticed the same as @cchan. Hoping we'll be able to maintain this.

28

Interesting... PurpleAir noticed that I was using the rollback API from my key, and someone contacted me about why I was using it. It sounds like there shouldn't be significant changes with the new API though.
I'm going to try to look at it this weekend, presume it's something relatively minor to do with either the request format or response parsing. I've dabbled with APIs, but not expert enough to tell off the bat what's going on.

29

Hi guys, there is a newer version up that should be working again.

3 Likes
30

Thank you!!!

31

You're welcome, it was a pretty minor fix. The new API wasn't supposed to change anything but it changed around the order that the results were sent back in. I'm also testing a better fix so that the order of the results isn't hardcoded to better handle future changes.

1 Like
32

Thanks, working great for me using a neighbor’s outdoor sensor. Is this confirmed working on private sensors? I’m looking at getting a PA-1 for indoors and registering it private. Thanks again.

33

Unfortunately I don't have access to a private device to test with, so I can't really say if it's working or not. I hope it is, and I'd like to get it working if there's any issue.

34

An updated version is now available that doesn't have the order of the results hardcoded, should make things a little more resilient in case of future API changes.

3 Likes
35

Just started using this driver, it is excellent. THANK YOU!

2 Likes
36

I get a NULL exception if I select just my own sensor instead of an area.
Fixed it with the following addition

Float distance(Float[] coorda, Float[] coordb) {
    if (coorda == NULL)
    {
        return 0.0
    }
    else
    {
    	// Haversine function from http://www.movable-type.co.uk/scripts/latlong.html
       ...

I also for my own use added temperature and humidity reporting because that's what the old driver used to publish, but looking at the API page they're not good data points since the sensor is inside the housing being heated by the electronics.

1 Like
37

Thanks, updated my driver to fix that issue

38

Would it be possible to draw up a driver that would instead of using the cloud, use the local network IP address to provide the data to hubitat?
Apparently MeteoBridge has done that and is pulling the data from the local IP.
The deeper reason are (1) emerging pay for service scheme at PurpleAir (2) sensors going broke (3) needing only local value (related to (1)).

39

I'm sure it would be possible, but I would consider that out of scope for this driver. I personally don't have a PurpleAir sensor of my own to use it with or test with.

40

@pfmiller does your driver support any of the recommended Purple Air correction factors such as LRAPA, WOODSMOKE or US EPA? These formulas compensate for the fact that the Purple air sensors don't properly measure the density of woodsmoke particles, which results in reporting an inaccurate AQI.

The screenshot below of slide 26 of this deck has the formula for the US EPA correction. The deck provides a through explanation of how they evolved these correction factors over several years.

If not already supported, would you consider adding this as an option to your driver?

Thanks!

Marc

image
image1182×637 129 KB

41

Hi Marc, I should be able to add some of those conversions, I will look into it!

42

@marcaronson408 Marc, I just uploaded version 1.2 with initial support for conversion algorithms. Please try it out and let me know how it goes.

FYI when conversions are applied the averaging period option is disabled because Purple air API doesn't provide that for some of the sensors used the the conversions.

43

Uploaded 1.2.3 which handles an error caused by devices with missing humidity data

44

I've uploaded version 1.3 which handles faulty humidity sensors (for those using EPA conversion), and also reduces API usage.

45

My apologies -- somehow, I didn't see this until today (Dec 31, 2023).

I updated and I see you have made a lot of improvements since the version I had. The ability to get a weighted average across multiple sensors is a very cool feature!

Any chance you could also expose the raw AQI in another attribute? I'd like to show both the raw AQI and the corrected value on my dashboard, as the corrected value is only appropriate if the air quality issues originate from wood smoke...

Thanks!

Marc

1 Like