Is there any method to hide advertise packet from nRF52 in the nRF Connect utils?

[Mikhail]

We want to use some device in the peripherial mode.

after the devices were bonded, for next connect I need to hide this advertise packet from air in the nRF Connect util. Is it possible?

I can hide name- works. 

Also I tryed (after has bonded) change 

BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE

to

BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE

At this case, there is no any device in the nRF connect but also can't connect to bonded device.

[ovrebekk]

Hi

After you have bonded to a device you can switch to directed advertising, which means you are advertising just to reconnect to that particular device. 

In directed advertising mode you don't include any of the normal data fields (name, UUID and so forth), just the BLE address of the device you want to connect to, and nRF Connect should not show anything. 

For more information about the different advertising types please have a look at the following article:
https://blog.bluetooth.com/advertising-works-part-1

Best regards
Torbjørn

[Mikhail]

Thanks, 

after device has bonded, which settings in the nRF52 should change to direct advertise?

[ovrebekk]

Hi 

You have to set the address of the device you want to connect to in the p_peer_addr field of the ble_gap_adv_params_t struct when you configure advertising. 

Best regards
Torbjørn

[Mikhail]

Thanks. So, if I want just advertise for a few devices, is there only one method- no name? Isn't it?

[ovrebekk]

Hi 

There are two methods to limit the number of devices that can send connection or scan requests:

1) Directed advertising, as described below. This only allows you to connect to a single device, and you will skip all the normal fields in the advertising payload. 

2) Advertising with white list: In this mode you don't change the content of the advertising payload, and everyone can read the advertising packet, but you will only accept connection requests or scan requests from devices that are stored in your white list. 

The advantage of this method is that you can have more than one device in the white list, but the drawback is that other devices can still read your advertising payload (if you want you could always remove the data fields from the adv packet if the devices in your white list don't need this data).  

Best regards
Torbjørn

[Mikhail]

Hi!

Thanks. It is clear. But I interesting- just hide my advertise device from nRF connect util. As I understand, if I need advertise for many devices- one way it hide name. Or I miss one more opportunity?

[ovrebekk]

Hi 

You can't really hide the advertise packet from nRF Connect if you want to advertise to many devices, but you can change the payload if you like. For instance you can remove the advertising name, and only advertise the advertising flags and your BLE address. 

You can also make the address of your advertiser private resolvable, which means the address will change periodically so that nRF Connect can not track your advertiser over time. Devices that are bonded to you can still recognize the advertiser, because they can resolve a static address from the private resolvable one. 

Best regards
Torbjørn

[Mikhail]

Hi!

I have sniff same device which is not visible in the nRF connect and visible in the sniffer.

I need make same. How it made in this sniffed device?

download from link (wireshark):

drive.google.com/.../view

[ovrebekk]

Hi Mikhail

I am a bit unsure what you are asking for. 

Are you looking for the code needed to make the nRF52 device duplicate the packet from the device you are sniffing?

Best regards
Torbjørn

[Mikhail]

Hi! Sorrry for delay with answer.

No! I need make my device like sniffed device. I mean- this sniffed device doesn't see in nRF connect. I see this device only in the wire shark sniffer. How to make my device with same behavoir? I mean- unvisible in the nRF connect?