Android NFC Pairing Issue

RE: Android NFC Pairing Issue

Simonr — Thu, 13 Feb 2020 08:57:25 GMT

Yes, this sounds reasonable. The same is the case for most Windows devices as well, filtering out Bluetooth devices that are "unknown" services, so I believe that's what you're seeing as well. You can test to confirm this by trying to connect to I.E. the ble_app_hrs example (the default one) using the Google Pixel's Bluetooth instead of nRFConnect.

Best regards,

Simon

RE: Android NFC Pairing Issue

sarem-shal — Wed, 12 Feb 2020 15:41:57 GMT

Hello,

I am using the default project the ble_nfc_pairing_reference example with "Just Works" Pairing.

But I ended up trying the BLE NFC Pairing with the two other experimental projects (ble_app_hids_keyboard_pairing_nfc and ble_app_hrs_nfc_pairing) and I actually saw a successful connection with the ble_app_hids_keyboard_pairing_nfc project. But when I tried the ble_app_hrs_nfc_pairing project, I saw the same behavior I was getting with the ble_nfc_pairing_reference project. Also if I run the non-NFC version the ble_app_hrs project, I'll see a similar behavior where I connected to the device through BLE and when I check my connected device, it does not seem to be actually connected.

I am suspecting that maybe on some phones (such as the Google Pixel 3a or the Samsung Galaxy 7), the default Android Bluetooth is only compatible with some services, otherwise it will disconnect/not connect fully. Hence the ble_app_hids_keyboard_pairing_nfc project was successful since my Google Pixel 3a and Samsung Galaxy 7 are compatible with that service.

Would you be able to verify my suspicion?

RE: Android NFC Pairing Issue

Simonr — Wed, 12 Feb 2020 13:15:25 GMT

Have you added any services to the ble_nfc_pairing_reference example? Because it shouldn't have any services by default. What pairing mode are you using, according to the example setup/testing page on the Infocenter, you can choose from the buttons on the board. Have you tried debugging at all on the nRF side, to see if you get any errors on that side of things?

Please also note that our experimental examples like the ble_nfc_pairing_reference example are prone to bugs, as they aren't tested thoroughly and are not to be revered as complete examples.

Best regards,

Simon

RE: Android NFC Pairing Issue

sarem-shal — Tue, 11 Feb 2020 19:17:13 GMT

Hi, so I re-evaluated the way my Google Pixel 3a connects and I may be seeing some of the behavior that you are seeing on your phone, but with some quirks in the behavior.

So as mentioned before, when I try to use the default Bluetooth NFC, my phone is able to successfully bond to the board.

My phone will say "PAIRING Nordic_NFC_PAIR_REF" and once paired it will say "Connecting Nordic_NFC_PAIR_REF"

When I look in my bluetooth settings, I see that the device is listed as a "Connected Device"

But, when I look at the device in my bluetooth settings, the phone does not recognize that it is connected to the board. In this context, I believe the Android OS is using the term "Connected Device" to refer to devices that is has bonded with.

After a few seconds go by, my phone will send the message "Could not connect Nordic_NFC_PAIR_REF" and when I relook at my Connected devices list, I no longer see the board as a bonded device.

I found a similar issue where something like this was documented on his thread https://devzone.nordicsemi.com/f/nordic-q-a/56739/ble-nfc-pairing-issue

The thread seems to suggest that my phone is disconnecting from the board because it does not recognize the service. Is there a work around for this that would allow a phone to recognize the service and stay connected? Specifically a work around for compatibility with the default Android Bluetooth.

Also when you run the project and connect to it with your phone, does the connection last or does it disconnect after a little while like it is on my phone?

RE: Android NFC Pairing Issue

Simonr — Thu, 06 Feb 2020 09:02:49 GMT

Thank you for confirming this wasn't a phone specific issue. I just tried this example on my Nokia 8.1 and was able to connect with a DK running the ble_nfc_pairing_reference example. I see the same message as you from the board's log, and my phone is able to connect to it. The screenshot below shows that it is connected via Bluetooth in the default Bluetooth menu (sorry about the Norwegian language, but it says "connected devices".

What error/message do you see on your phone exactly? I had to disable Bluetooth on my phone in order to discover the NFC device at all, but I think this might be a phone-specific bug.

Best regards,

Simon

RE: Android NFC Pairing Issue

sarem-shal — Wed, 05 Feb 2020 15:43:10 GMT

Hi, so I tried connecting to the board with a Samsung Galaxy 7 and I saw the same behavior where the built-in NFC was able to bond but could not connect. But, it was able to connect fine through the NRF app. Could this just be a limitation of the application or board where it can not do a BLE connection without an app (such as the NRF connect app)? Or could it be that the phone itself does not recognize the service without the app?

RE: Android NFC Pairing Issue

Simonr — Wed, 05 Feb 2020 12:44:53 GMT

Have you tried your application with any other phones than the Google Pixel 3? We had an issue some time ago which turned out to be specific to the Google Pixel 3 and 3XL, and apparently there are some issues with the NFC support on that particular phone, as the NFC application that time was able to connect with any other phones supporting NFC but the Google Pixel 3 and 3XL. Even Google Pixel 1 and 2 were able to, so there are some issues with the NFC on that particular phone I'm afraid. Here's that case for reference.

I suggest you test with another phone before looking at your application.

Best regards,

Simon