A strange “spooky action at a distance” issue…
Have a very simple, custom PCB which we solder Photons to. It just exposes some of the I/O onto connectors. There is a capacitor on the 3V3 to GND pins and as well as some others, and that is about it.
The PCB meets with the Particle ground plane recommendations.
With a constructed PCB, I place the Photon into listening mode and try to connect to it using a laptop or mobile phone. Neither client was able to connect, complaining “Connecting” as it is unable to obtain an IP address, rather than “Connected”.
The problem was consistent for a number of boards that I tested. Signal strength was a.okay, measured -30 dB.
Suspecting hardware, I took a fresh Photon out of a tray and was able to connect to it in SoftAP mode consistently. This is good and expected.
Next, I placed the same Photon onto a PCB which only had the capacitors loaded, but just holding it on carefully by hand (yeah, I know…). It consistently failed, just like the soldered boards.
This points to the PCB, but everything else works, Specifically it can connect to our AP and can transact with the Particle cloud.
Then did this experiment. Placed sticky tape over the pads on the PCB so that the Photon could not make electrical contact. Held it gently in place by holding the connector on the USB cable, not the board.
It still failed!
Next I lifted the Photon 1 mm above the PCB and so on until it eventually passed at 4 mm above the board.
Problem for us that we have gone into a pilot 100 unit batch production without testing this particular functionality until now… yikes!
Any clues as to what might be going on here? Really hoping that it can be fixed in firmware…
PS - I note this post for the record: