Sensor on PM2 port on new AirGradient Open Air not reporting data

I have a new AirGradient Open Air with v1.1 main board.

It’s not reporting data and I suspect it’s an issue with the PM2 sensor port (or firmware).

It showed an initial connection to the dashboard when I set it up, but it never reported any data (I assume because no PM2 data). To troubleshoot, I flashed several different ESPHome configurations. The PM2 sensor never reported data with any of them.

One thread suggested the different arduino versus esp-idf toolkits might make a difference for the 2nd UART, but testing with both revealed no difference in behavior (PM2 never reports data).

I do not think either the sensors or cables are fault:

  1. Both sensors, when plugged into PM1, will work and report data.
  2. I tested both combinations of sensors and cross-over cables on the PM1 port. Both combinations functioned normally.

Something is up either with the PM2 port hardware or the firmware. PM1 and PM2 both seem to power the sensors, as I hear fan noise on both sensors, but never get any data from PM2 (with either sensor).

  1. Stock firmware: connects to dashboard, but never shows any data.
  2. ESPHome with various configurations: can reliably get data from PM1 port but never anything from PM2 port.

I can’t see any issues with the mainboard. Solder connections and traces look good by an amateur’s examination.

Troubleshooting recommendations?

Log excerpt from ESPHome:

17:41:13 [D] [sensor:094] 'Outdoor PM<1.0µm Concentration': Sending state nan µg/m³ with 0 decimals of accuracy
17:41:37 [D] [sensor:094] 'Outdoor Relative Humidity': Sending state nan % with 1 decimals of accuracy
17:41:38 [D] [sensor:094] 'AQI: Minutes Remaining': Sending state 1076.00000 minutes with 0 decimals of accuracy
17:41:38 [D] [sensor:094] 'NowCast: Minutes Remaining': Sending state 716.00000 minutes with 0 decimals of accuracy
17:41:47 [D] [sensor:094] 'Outdoor PM>2.5µm Count': Sending state nan /dL with 0 decimals of accuracy
17:41:49 [D] [sensor:094] 'Uptime Sensor': Sending state 167.75000 s with 0 decimals of accuracy
17:41:52 [D] [sensor:094] 'Outdoor Temperature': Sending state nan °C with 1 decimals of accuracy
17:41:52 [D] [sensor:094] 'Outdoor PM>0.5µm Count': Sending state nan /dL with 0 decimals of accuracy
17:41:53 [D] [sensor:094] 'Wifi Strength': Sending state -45.00000 dBm with 0 decimals of accuracy
17:41:54 [D] [sensor:094] 'Outdoor PM<2.5µm Concentration': Sending state nan µg/m³ with 0 decimals of accuracy
17:42:01 [W] [pmsx003:150] PMSX003 length 57856 doesn't match. Are you using the correct PMSX003 type?
17:42:37 [D] [sensor:094] 'Outdoor Relative Humidity': Sending state nan % with 1 decimals of accuracy
17:42:38 [D] [sensor:094] 'AQI: Minutes Remaining': Sending state 1075.00000 minutes with 0 decimals of accuracy
17:42:38 [D] [sensor:094] 'NowCast: Minutes Remaining': Sending state 715.00000 minutes with 0 decimals of accuracy
17:42:49 [D] [sensor:094] 'Uptime Sensor': Sending state 227.75000 s with 0 decimals of accuracy
17:42:52 [D] [sensor:094] 'Outdoor Temperature': Sending state nan °C with 1 decimals of accuracy
17:42:53 [D] [sensor:094] 'Wifi Strength': Sending state -42.00000 dBm with 0 decimals of accuracy
17:42:56 [W] [component:204] Component interval took a long time for an operation (0.98 s).
17:42:56 [W] [component:205] Components should block for at most 20-30ms.
17:42:56 [W] [component:205] Components should block for at most 20-30ms.

Please send some pictures of you assembly. Especially around the cable and plugs.

Also ensure you have really plugged the plugs in firm enough.

Do you hear the fan spinning in the PM sensors?

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Also ensure you have really plugged the plugs in firm enough.

Yes, the plugs on both ends are seated.

I can confirm because both sensors work fine when plugged into the PM1 port. It’s only the PM2 port with an issue.

Do you hear the fan spinning in the PM sensors?

Yes, both sensor fans are audible when connected to either PM1 or PM2. Never any data from PM2 port, though.

(splitting these out over multiple posts because, “new users can only put one embedded media item in a post.”)

This is indeed strange. It could be a connection issue on the esp32 pins which are not visible from outside.

Can you please contact our support with your previous order number and we will send you a new board.

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The new board came today. Started reporting immediately after getting things set up, the replacement board resolved the issue.

If you want the old one back or if I can otherwise provide you with any information let me know.

Appreciated!

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Great that fixes the issue. You can keep the board. You could probably build a second one with only one pm module.