One Qt Py esp32-c3 not connecting to wifi

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abbogart
 
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One Qt Py esp32-c3 not connecting to wifi

Post by abbogart »

Grabbed two qt pys the other week along with some 3d printed snap cases to build a few environmental sensors for my place. I'm having trouble connecting one to wifi--it immediately disconnects, and refuses to attempt to reconnect. I've tried a few things:
  • Ran WifiScan and WifiClientConnect example on both Qt Pys, as well as another Lolin C3 Pico I had laying around. Both "good" boards connected to my router right away. (So it's probably not the router?)
  • Ran through the Qt Py esp32-c3 tutorial with the "bad" qt py. I was able to get in and out of bootloader mode, as well as flash the built-in Neopixel (so I didn't wedge the chip?)
  • Tried WifiScan/other Wifi examples on the "bad" board with reduced frequency (80Mhz vs 160Mhz), and also tried disabling Wifi 6 features on the router. No change.
The actual bug is pretty weird--the "bad" board can see the list of networks just fine, but fails to connect to any network.

Is there maybe something I'm missing here? Is it possible to wedge an esp32 so it can only do RX for WiFi? Or did I just get unlucky with the chip I got?

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adafruit_support_mike
 
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Re: One Qt Py esp32-c3 not connecting to wifi

Post by adafruit_support_mike »

It's most likely to be a transmission issue. The QT Py can see the router, but that doesn't automatically mean the router can see the QT Py.

If you have a diagnostic interface for the router, check that to see if you can find evidence of the QT Pys trying to connect. The most valuable piece of information would be the RSSI at the router.

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abbogart
 
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Re: One Qt Py esp32-c3 not connecting to wifi

Post by abbogart »

Interesting... I'll check! here's what I see:
  • "good" qt py: (in the same room as the router) I see -58dBm, connected as 802.11n.
  • "bad" qt py: (in the same room as the router) it won't connect, so the asus dialog won't pick it up.
I did try running a softAP on the qt py as well. I can't seem to get actual RSSI information, but from a foot away I'm seeing full bars on my mac. I can't connect to the AP, but at least I can see that it's broadcasting strong enough. Does that help? I can't find another way to get RSSI for a network I'm not connected to on mac.

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adafruit_support_mike
 
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Re: One Qt Py esp32-c3 not connecting to wifi

Post by adafruit_support_mike »

Let's see if there are any obvious problems with the hardware.

Post a pair of photos showing the front and back of the bad QT Py please.. well lit with enough focus to see details of the components and solder joints please. 800x600 images usually work best.

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abbogart
 
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Re: One Qt Py esp32-c3 not connecting to wifi

Post by abbogart »

Okay, so I think we found the issue. The front and back images are here:

https://share.icloud.com/photos/08egSuQ ... 9tWeATDeLQ

The bottom left on the back of the board shows an itsy-bitsy smd component that has one side lifted off of the board? Could that do it?

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adafruit_support_mike
 
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Re: One Qt Py esp32-c3 not connecting to wifi

Post by adafruit_support_mike »

Yep.. that capacitor squirmed in the reflow oven.

That's a production defect, so let's get you a new board: Send a note containing a link to this page and your order number to [email protected]. The folks there will get you a replacement.


If you're comfortable soldering, you can probably fix the board. I generally use a piece of 24-gauge solid wire as a probe for that kind of thing: you place the wire in contact with both ends of the component, then touch the tip of your soldering iron to the wire about 1/8" away from the solder joints. The wire carries heat to both ends of the component, leaving it free to move.

Surface tension will make the part stick to the wire, which allows easy repositioning. Once you get the component oriented over the pads, use the same trick to melt the solder on both pads at the same time. Once the solder on both pads and both ends of the component are liquid, they'll want to merge as soon as they can.

Keep the wire hot as you pull it away from the component and pads, and you should get perfect placement and perfect joints.

Use plenty of flux throughout the process. Molten solder flows best and has the highest surface tension when it's clean and isolated from air. Joints merge and take the correct shape because that's what the metal wants to do.

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abbogart
 
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Re: One Qt Py esp32-c3 not connecting to wifi

Post by abbogart »

Thanks Mike, I appreciate it.

Unfortunately I don't have any soldering gear (or a safe place to do so) right now :(. That's one of the reasons I went with the Adafruit Stemma ecosystem (which is great!).

I tried bending the component back into place, which was (predictably) a bad idea. The capacitor came off and vanished into the aether. For future reference, which cap was it in the schematic? If I can someday I'd replace it and see if I can get the board working again. In the meantime I may take you up on your replacement offer.

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adafruit_support_mike
 
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Re: One Qt Py esp32-c3 not connecting to wifi

Post by adafruit_support_mike »

The part is a 16pF 0402 capacitor. They're inexpensive and easy to get at Digikey or Mouser.
abbogart wrote: Thu Mar 09, 2023 12:02 pm In the meantime I may take you up on your replacement offer
Please do. We take QA seriously, and you paid for a working board.

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abbogart
 
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Re: One Qt Py esp32-c3 not connecting to wifi

Post by abbogart »

Hi all! I wanted to update here because I think I figured out what's happening. It's the 3d printed Qt Py snap case. The edges of the snap fit for the Qt Py eventually push the leg of the capacitor off of the solder pad. My other original order C3 failed today. (The replacement is working just fine, so maybe it is just the board, I guess we'll find out).

For those who are putting esp32-c3s in snap cases: if it works, don't touch it.

For Adafruit: you may want to make a note that the components are real close to the edge on the C3 board, and anything less than a perfect print will damage the board eventually. I may try this again with an S2 board since that's the one in the snap case guide, but the project is feeling like a dud at this point.

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abbogart
 
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Re: One Qt Py esp32-c3 not connecting to wifi

Post by abbogart »

For what it's worth:
  • The prints are well done with no sharp edges
  • I was able to bend back the cap this time and get wifi access again. I put it back in the case with predictable/unfortunate results.

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adafruit_support_mike
 
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Re: One Qt Py esp32-c3 not connecting to wifi

Post by adafruit_support_mike »

Hmm.. I'll mention that to the folks that wrote the tutorial. Thanks!

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