can't scan using android

[Youngjun]

Hi,

I'm using nRF52810 with custom pcb antenna.

When i scan my device using nRF52 DK and nRF Connect in windows 10, my device scanned.

But, when i scan my device using android smartphone(samsung gallaxy note9, samsung gallaxy tab1, tab2, tab3), i can't see my device in scanned list.

The antenna power of my device is about -67dbm.

Is this problem of custom antenna?

I designed antenna by referring to nrf52840 dongle.

This is my second board

 

Thansk.

This is my first board.

It's work well.

[Simonr]

Hi

I assume you're scanning for this device in the Bluetooth menu in the Android settings, am I right? If so, please try scanning using the nRFConnect app for Android, as the "default" Bluetooth scanner won't pick up all devices, but restrict itself to HID devices and head phones, etc. while the nRFConnect app should pick up anything.

It is also worth mentioning that this antenna doesn't seem optimally tuned, and I think it should be possible to increase the radio performance slightly, but I don't think this is why you don't see the device advertising on the Android devices. Check out our Antenna tuning whitepaper for reference.

Best regards,

Simon

[Youngjun]

Hi.

I'm using ble_app_hrs and ble_app_uart.

My first board scanned on android.

I think difference of my first board and second board is antenna and 32MHz crystal.

When i download code at first board, it's work.

(This board scannes at android bluetooth menu.)

But, when i download same code at second board, it's not scanned.(It scanned just windows)

I thought 32MHz crystal is not the problem.

Because my secons board can advertise and connected in windows.

I added picture of my first board.

It's weird.

I tried to scan using nRF connect(android).

But, nRF connect also can't scan.

[Youngjun]

I tested using another tablet.

And, some android device can't scan.

It's weird.

I should test various android device.

[Eugene Yu]

Hi,

It might be related to a 32MHz crystal.

Each Android device has a different deviation for the 2.4GHz.

So if your device drifted the 2.4GHz frequency out of the Android device range, it will not be scanned.

I recommend you check the frequency drift with a spectrum analyzer.

Thanks,

Eugene