Qwiic SHIMs - Power to Attachments but no data

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cordelya
 
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Qwiic SHIMs - Power to Attachments but no data

Post by cordelya »

I have in my possession three SparkFun Qwiic SHIMs. Two of them arrived together from Adafruit as part of the same order last week. The third arrived today from a different source - for comparison. Here's what I know:

The two I ordered from Adafruit both behave the same way. I wanted to be certain that it wasn't because both of them don't friction-fit well (they both wiggle), so I soldered a 2x3 socket header onto one of them. When contact is made with the GPIO pins, they both supply power to the two connected devices (an SCD-30 board and an LPS22 board). Both connected devices work (also tested on a Qwiic pHAT to confirm). When I run i2cdetect for either one, these are the results I get:

Code: Select all

pi@[redacted]:~ $ i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- -- 
When I test with the Qwiic SHIM I got from elsewhere (which *also* wiggles, but that's beside the point), I get the following result:

Code: Select all

pi@[redacted]:~ $ i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- 5d -- --
60: -- 61 -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
The shown testing was done using a Raspberry Pi Zero W, with no other devices connected to the GPIO at the time of testing.
I ran the same tests on a Raspberry Pi 3 and received the same results.
Ran the same tests with other sensors attached, same results.

The attached images show the three Qwiic SHIMs together, each taking a turn on the GPIO.

Will add 4th photo (close-up of my soldering) in a reply because I suspect someone might ask for that.
Attachments
The other-source SHIM seated and illuminated.
The other-source SHIM seated and illuminated.
20210920_193718.jpg (231.76 KiB) Viewed 150 times
The unsoldered SHIM from Adafruit seated and illuminated.
The unsoldered SHIM from Adafruit seated and illuminated.
20210920_193626.jpg (216.14 KiB) Viewed 150 times
The SHIM from Adafruit with 2x3 socket soldered on, seated and illuminated.
The SHIM from Adafruit with 2x3 socket soldered on, seated and illuminated.
20210920_193503.jpg (204.16 KiB) Viewed 150 times

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cordelya
 
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Re: Qwiic SHIMs - Power to Attachments but no data

Post by cordelya »

Here is the close-up photo of the solder joints.
Attachments
20210920_193830.jpg
20210920_193830.jpg (96.56 KiB) Viewed 149 times

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mikeysklar
 
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Re: Qwiic SHIMs - Power to Attachments but no data

Post by mikeysklar »

@Cordelya,

The soldering looks shorted in the final photo provided.

Please go over this again and make sure you have no solder touching between pins. Use a multimeter to verify if necessary.

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cordelya
 
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Re: Qwiic SHIMs - Power to Attachments but no data

Post by cordelya »

I tested the soldered shim with a multimeter. Only 2 adjacent pins that set off the continuity beep were 2 & 4. Cleaned up solder. No dice. I'm done with that one.

The shim I didn't solder a header to, I finally got to work, but look at how much angle is needed to make full contact:
20210923_103549-cropped.jpg
20210923_103549-cropped.jpg (467.78 KiB) Viewed 136 times
20210923_103216-cropped.jpg
20210923_103216-cropped.jpg (765.05 KiB) Viewed 136 times
That's a removable port cover from a GoPro camera wedged under there to keep it in place because otherwise it moves.

Needing that much angle means I cannot sandwich it between the RasPi and a HAT, which is the purpose I bought it for. Will be pivoting to a different Qwiic adapter entirely because continuing to fuss with this $1.50 part is not worth my time.

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adafruit_support_bill
 
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Re: Qwiic SHIMs - Power to Attachments but no data

Post by adafruit_support_bill »

The shim I didn't solder a header to, I finally got to work, but look at how much angle is needed to make full contact:
Through holes are designed to be soldered to header pins. They are not connectors in and of themselves and cannot be expected to make reliable electrical contact to header pins without solder.

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cordelya
 
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Re: Qwiic SHIMs - Power to Attachments but no data

Post by cordelya »

The product page (https://www.adafruit.com/product/4463) says,
The SHIM design allows you to plug directly to the Pi's I2C bus with no soldering required, and the thin PCB design allows for it to be sandwiched on your Pi GPIO with other bonnets or HATs! The Qwiic SHIM works great if you want to add a Qwiic connector to your Pi simply and easily with no soldering required.

The Qwiic SHIM uses a unique friction-based connector that wedges itself onto the GPIO header for a secure, solderless connection.
The product description on the SparkFun page says the same thing.

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adafruit_support_bill
 
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Re: Qwiic SHIMs - Power to Attachments but no data

Post by adafruit_support_bill »

Hmmm. Interesting design, but it looks like a lot of users reporting the same problems in the reviews on the Sparkfun site. They'd need to hold pretty tight tolerances for that design to consistently work well as a friction fit. If they are not usable for your application we can issue a refund. Please contact [email protected] with a link to this thread.

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cordelya
 
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Re: Qwiic SHIMs - Power to Attachments but no data

Post by cordelya »

Email sent!

I'm disappointed (in SparkFun) that these don't live up to the hype. Especially since I got a third one from a different source and it fits nearly as poorly.

For the record, I also ordered a pair of Pimoroni LED SHIMs in the same order. Both of them friction-fit as advertised and they accomplish that quite well. I like them quite a lot.

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