My PurpleAir


Setup: Enter your sensor's IP address, then add the app's complication to the watch face.

The app always shows -- for the air quality. The app must be on the same LAN as the sensor. If your watch is using its companion phone for network access, the phone must be on the same LAN as the sensor, too. If the companion phone is off or out of range, try to turn the watch off and back on so it stops trying to use the companion phone. WatchOS really wants to use its companion phone for network access. I also suggest that you use static DHCP on your router so the sensor always has the same IP address.

What is the exact AQI? The app shows the PM2.5, "120 second average refreshed every 10 seconds" on the sensor's built in web page. It averages the A and B channels. Specifically, the pm2.5_aqi and pm2.5_aqi_b fields from the json API. You can see same numbers by pointing a browser at http://device_address/json

How often does the app refresh the AQI? The app updates the AQI every 15 minutes, and when you open the app or restart your watch. If the app can't reach the sensor for more than 20 minutes, it changes the AQI to --. It can take up to 3 minutes for the app to find the sensor after connecting to the LAN. The complication refreshes approximately every 15 minutes.

The Save button doesn't appear on the address editor page. Only non-routable, IP4 address can be entered. That is, an address in the form Non routable IP addresses start with 10, or 192.168, or 172.16

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