Display, Temp, and RH stopped working

Hi all, everything was working great – see video 2021-12-26 First AirGradient DIY Kit Assembled - YouTube
2021-12-26 First AirGradient DIY Kit Assembled - YouTube – and then I went to demonstrate it to my sons before I had put it in the enclosure.

One grabbed it without being grounded (they’re young and I haven’t yet trained then on handling sensitive electronics).

I think there was a static discharge. The display stopped working, so I recompiled and reloaded it with Wi-Fi enabled, and was able to connect it up to the home Wi-Fi, pushing data to AirGradient’s site.

  • I’m getting seemingly valid CO2 readings – they’re nearly the same as I got yesterday when the display was working
  • The temp is incorrectly reporting 32F
  • The RH is incorrectly reporting 0
  • The PM2.5 appears to be working as it is normally measuring 0…and I was able to get it to spike when I melted some 60/40 rosin solder near the intake

I checked the continuity from top of pin on the display to bottom of pin below the PCB and all of the pins are reporting.

Is there some way I can see if the problem is the display, the I2C controller, …what else? If a semi-conductor is fried, I need to know what to replace.

Are the through-holes on the side of the PCB for testing – the 5x4 grid labeled 5v, 3v, G, SDA, SCL with holes for TX, RX, D7, D8, and D9? If so, how do I use them for testing? I only have a multimeter and a USB console cable…no oscilloscope yet…

Thanks in advance for your help!

@theschles
I had hardly any OLED displays dying after many school projects. I think it might be something else. Are you sure there is no issue with the soldering?
Can you post some high-resolution images of all parts (both sides of the PCBs) and I can have a look?

I just built a pair of DIY kits, and I have the same issue with one of them.

The display doesn’t work and temp/RH are both 0, but everything else (WiFi, PM, CO2) works fine.

I swapped out the OLED shields, which didn’t change anything, so I know the issue is not there.

(The other one I built works great!)






The OLED and Temp/Hum sensor both use the i2c bus so they share the same lines.
If you swapped the OLED display, it cannot be that but maybe there is some kind of short around the Temp/Hum sensor.
image
image

Maybe try to resolder these points.

Thanks! I tried resoldering those on both sides, but no dice. It’s possible i have a bad joint on the processor board, but I’m not sure how I’d get at them.

Anyways, it’s not a huge loss, as for one of them I wasn’t really going to be using the display, and am mostly interested in CO2 and PM2.5.

Hi all,

So I desoldered and re-soldered the pins on the display board…and when I went to re-attach it to the pin headers on the ESP, I cracked the display :frowning:

I did try to desolder the ESP pins off of the AirGradient custom PCB so I could remove the PCB…and could not figure out how to get them to fully release. Might I suggest for the next rev to find a combination ESP, Wi-Fi, and display all-in-one…and have us solder headers onto the AirGradient custom PCB so one can isolate lines for continuity and short debugging?

@theschles I will send you a new display. Can you please send me an email with your address? Thanks.

Hi @AirGradient Thank you that’s very kind of you – but I’ve got five other kits to assemble — and by the time I’m done with those (I’m slow, welcome to 3 kids, a wife, and a job) the replacement display should be here from AliExpress

Ok thanks for letting me know.