PM reading fluctuates between '0' and '-'; and other experiences

Components
#1

I just received and set up the DIY pre-soldered kit for the airgradient one.

My experience this far:

  1. The unit did not flash using the webtool. Kept getting an error message in the browser when trying to connect to the unit (my computer detected the unit fine, but the webtool could not execute the flash). So I am working of the firmware it shipped with.

  2. Wifi connection went off without a hitch.

  3. I had trouble initially, but was able to enter the config mode to turn off the LEDs.

  4. The PM sensor does not appear to be functioning. It keeps changing from ‘0’ to ‘-’, every so often (like 30sec-1min intervals). Lighting a candle under the unit does activate a reading, but it is very low (and very delayed), never breaking 130 ug/m3. Removing the candle reverts the reading back to 0.

  • Even putting the unit inside my 3D printer enclosure yields no readings (my main purpose for purchasing the unit).

Any assistance with 1 and 4 above would be greatly appreciated. I tried searching the forum using the search bar, but the function appears very limited.

#2

I would try again to use the web flash tool to make sure you are on the latest firmware. Sometimes errors with it can be resolved using this method:
The AirGradient ONE Air Quality Sensor (Presoldered-Version, PCB Version 9)

Do any other sensors reset or show NaN when the PM changes to -? Do you see any messages about configuring the device or holding a button, that would indicate it was rebooting?

#3

Other sensors have values. I do have another air quality sensor device, comparing the two (AQ1 vs uHoo)

Value: // AQ1 : uHoo
CO2 // ~840 : ~857 ppm
PM2.5 // 0 : ~110 ug/m3
TVOC // 100 : 0 ppb
NOx // 1 : 35 ppb (uHoo labels this NO2)

Device does not reboot on its own.

#4

CO2 is pretty comparable
PM2.5 showing consistently 110 is pretty high. I see 0-3 indoors and 5-25 outside most days
TVOC is shown as an Index value with AirGradient, so 100 is an even baseline, higher numbers (up to 500) means worse air, and lower than 100 means an improvement. Same with NOx

Your uHoo is giving an absolute value, so you will get different numbers, but if they are graphed, hopefully they correlate.

#5

I will try flashing again, right now the PM says “-”.

#6

I was this time somehow (not sure how) able to get to the point where it asks me if I want to install or see the logger. I am able to see the logger but the install function doesn’t work, not sure exactly how and when to hold down boot sw button.

“Failed to initialize. Try resetting your device or holding the BOOT button while clicking INSTALL.”

#7

Ok, just tried to start for scratch and now I’m locked out from connecting to it again…

“Failed to execute ‘open’ on ‘SerialPort’: Failed to open serial port.”

#8

Using the link I posted earlier, you would unplug the USB, hold the button while plugging in the USB and then try to flash through the website. But at this point you may need to close/open your browser or even restart your computer if the com port got hung up by something

#9

Ok… while the unit was powered on, I held down boot SW and then hit En button, then tried again.

That seemed to work and it is flashing. restarted device, same issue it seems with pm saying ‘-’

#10

Keeping it inside the 3d printer case while printing yields exact same readings as outside the case:

CO2: 840
PM2.5: - or 0
TVOC: 101
Nox: 1

That just can’t be right?

#11

I don’t think a - for a reading makes any sense, so I suspect it isn’t working reliably. May want to open the case and make sure the ribbon cable to the PM2.5 sensor is seated well.

@Achim_AirGradient will also see this soon and can offer some other suggestions.

#12

For what it is worth, I don’t typically see an increase in PM2.5, or NOx when printing with PLA, and VOC only goes up a bit when using the filament I typically use, Hatchbox and Sunlu.

#13

I am using hatchbox as well. I did check the cable seating.

I look forward to Achim’s thoughts…

#14

Could you post some photos from the pcb of the monitor (with all it sensors connected)?
Also please check off the shall pm cable has some damage?
Finally can you try a different power supply