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?

[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?

[ovrebekk]

Hi

You might have to bypass the SoftDevice to do this. If you access the radio directly you get full control of the data payload, and you can send any type of packet that you like. 

Are you able to send me the information from the sniffer showing the data content of this packet?

Best regards
Torbjørn

[Mikhail]

https://drive.google.com/file/d/16DzY4MQ0KPc5IPIK1UFsdZsiD96hLjRP/view?usp=sharing

This is link to same device wich advertise and I can't see it in the nrf Connect.

Also I don't want to use bypass SD. I want to use SD and want to make invisible only in the nrf Connect via standart functions.

[ovrebekk]

Hi Mikhail

Thanks for the sniffer log. 

Based on this I can't see why the packet shouldn't show up in nRF Connect. It looks like normal advertising to me. 

What platform/phone are you running nRF Connect on?

Do you have some other platform available that you can test on, to see if it doesn't show up there either?

Best regards
Torbjørn

[Mikhail]

Hi!

I run nRF Connect on a android platform.

I tested this sniffed adv device on another platforms- same behavior- can't see in the nrf connect.

But in the another mode of this device I can see it in the nrf connect. But I can't see it only in this mode. See only in ble sniffer.

My be it used direct advertise mode ? Or it used whitelist for advertise? 

[ovrebekk]

Hi Mikhail

It didn't use directed advertising, no. Based on the log it is normal, un-directed advertising. 

It might have used whitelist, but whitelisting doesn't make the advertise packet invisible to other scanners. It only means that other scanners will not get a response if they try to send a scan or connection request to the advertiser. 

When you say other platforms, did you also test in nRF Connect for Desktop?

Unfortunately I won't be able to follow this up until after Easter, as I am leaving for vacation (I'm back in office on the 23rd of April). 

Best regards
Torbjørn