We tried this approach for testing the U1 at the beginning but couldn't find any significant indicator to test the success of the soldering.
Checking for shorts is a good idea, but in our experience the most common problem are unconnected pads. And that's really difficult to test.
The only way we found to check this component is... reading a register with i2c 😈
Since we needed to do it all the time we made a pogobed that worked like a charm
here you can see @LeoDP using it:
But, I guess building it for just one set of sensor is not worthy. I think a minimal configuration to test with i2c on an unpopulated board would be to temporary solder SCL and SDA lines to JP1 and JP2 (on the inner pads) and the pullup resistor on R3.
Once everything is wired you can issue from your Raspberry:
i2cdetect -y 1
You should get a possitive on the addresses 6B and 1C if the sensor is correctly soldered.
I'm not sure if the absence of the capacitors around U1 might disturb this test. If you can't get readings try adding them, starting with C2, C3 and C4.
Again, that is our experience.. if you find a simpler test I would love to know it.
