PM2.5 sensor and CO2 sensor suddenly stopped, this happened three times yet

[jcfraileb]

Hi, I purchased a non-assembled monitor kit and completed the installation successfully. However, after about 10 days of outdoor deployment, I’ve encountered recurring issues that require me to uninstall, reboot, and open the enclosure.
Specifically:

• The PM sensor has stopped reporting data twice
• The CO₂ sensor has stopped reporting data once
• Today, the issue occurred again with the PM sensor

In all cases, the system recovers only after reconnecting components. So, based on this behavior, I suspect the issue may be related to:

• JST connector reliability at the microcontroller interface
• Possible sensitivity to vibration or slight mechanical movement
• Potential instability after power interruptions (e.g., during electrical storms)

Given that this system is intended for outdoor deployment, I would like to understand:

1. Is this behavior expected under field conditions? What can I do?
2. Are there recommended best practices to improve connection stability or prevent sensor disconnection?
3. Do the assembled monitors include more robust or reinforced internal connections?
4. Is there any firmware-level solution (e.g., automatic sensor reset or watchdog) to handle these failures?
   I am planning to deploy a local monitoring network, but these issues are concerning, especially if they could persist in assembled units. Distance and time are invaluable in monitoring, but we are so far apart that I am concerned about product guarantees. I would really appreciate your guidance on how to improve system reliability in outdoor conditions.

Model: O-1PST
Monitor Serial Number: 34b7da9fa514

Thanks

[Tai_AirGradient]

Hi @jcfraileb, welcome to our community!

Would you mind sharing some pictures of the inside of your monitor (mainboard, connectors, sensor modules, etc.)? Thanks!

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1. Is this behavior expected under field conditions? What can I do?

No, this is not an expected behavior. Apart from using a reliable power supply (USB charger), you might want to:

• Physically inspect that each the PCB is in good condition, and all sensors are connected to the right port and fit properly tight to their port. Please refer to: https://youtu.be/y9M5bJkwK4Y?si=Tjy6ke6a3fgKOc_B .
• Physically inspect that all cables are in good condition, not crushed or damaged by the plastic enclosure rift.

2. Are there recommended best practices to improve connection stability or prevent sensor disconnection?

• Use a reliable 5V 2A USB power supply and cable.
• If possible, it is recommended to mount the monitor where it’s not exposed to the sun or rain directly. Make sure it is installed on a stable wall or pole that won’t wobble.
• Make sure there’s no physical damage (as mentioned in 1.), and mount the monitor properly to avoid hardware damage from the environment. See this for more info about mounting: https://www.airgradient.com/documentation/kb/kb-diy-airgradient-open-air-installation-instructions

3. Do the assembled monitors include more robust or reinforced internal connections?

• There is no difference in hardware components between the DIY kit and the fully assembled. The only difference is that the fully-assembled units are tested in our test chamber, so you’ll have a test report (shown inside your Dashboard).

4. Is there any firmware-level solution (e.g., automatic sensor reset or watchdog) to handle these failures?
I am planning to deploy a local monitoring network, but these issues are concerning, especially if they could persist in assembled units. Distance and time are invaluable in monitoring, but we are so far apart that I am concerned about product guarantees. I would really appreciate your guidance on how to improve system reliability in outdoor conditions.

I wonder if @Samuel_AirGradient has some insights on this?

[jcfraileb]

Thanks for your answer. I already reviewed each point you suggested, and everything is ok. So, I don’t know what the problem is. Sometimes the CO2 doesn’t work, and sometimes it’s the PM sensor which stop measuring or both of them. I tried to reinitiate the power cycle, resetting the device by USB-PC, unassembling… I did a test in another location too. The sensors measure well and are functional, but the connections are not stable; they work well for two to three days and suddenly stop… Maybe anything about the microcontroller or JST cables?
However, I attached some pictures and screenshots.

[jcfraileb]

[jcfraileb]

[jcfraileb]

[Tai_AirGradient]

Hi @jcfraileb, thank you for providing more info about this.

It seems the JST connectors are not securely plugged into the socket. Could you please check and ensure the connection, then let your unit run and see if the sensor dropouts still occur.

Here’s what a fully-assembled unit looks like:

Please feel free to let me know if you need further assistance. Thanks!