What usb cable to use to connect the raspberry with the photon

Troubleshooting
1

Hi,

I’ve got my brewpi up and running but am having some problems with the usb cable connecting the raspberry with the photon.
Out of all my cables I’ve got lying around the house, the only one I can make it work with is the one that came with my kindle. For every other one I’ve tried I can’t get a connection, just this error in the log:

Sep 01 2016 17:42:02   Opening serial port
Sep 01 2016 17:42:12   Errors while opening serial port: 
Could not find compatible serial devices

I’ve tried maybe 5 different cables with the same result.

The problem is, I want to keep that cable for my kindle since it’s the only one I can get the kindle to connect to my computer with, and thus not use it for my brewpi.

So, the question is, how do I find a usb cable that will work? I’ve browsed some online shops today but can’t really see if there’s any difference between different cables and / or manufacturers.

I’ve also tried powering the spark separately but that doesn’t seem to make a difference.

Or is it the power supply for the raspberry who’s at fault? I’m currently using a somewhat cheap deltaco phone charger that came bundled with my raspberry.

2

A bit of an update!

I tried the usb cable that came with the deltaco charger, and that cable worked!
So I guess my problem is solved for now, but the question still stands, how to distinguish a “good” cable from a “bad” cable? Other than testing that is…

3

A phone charger to power the raspberry pi sounds like a bad idea. I think this is definitely a factor. You really need a good 2A power supply to run reliably.

4

Yea I thought about that as well. However, the charger is rated at 5V, 2A output. Shouldn’t that be enough?

5

Purely based on the specs, yes, that should be enough.
But still, I have heard many cases of phone chargers causing problems.

If it is not the charger, it is often the USB cable that has a too high resistance. Official Raspberry Pi power supplies have a non-detachable cable with a lower resistance than USB cables, causing less of a voltage drop over the cable.