How to find if any Central Device is listening to Advertising data ?

RE: How to find if any Central Device is listening to Advertising data ?

endnode — Tue, 29 Mar 2016 19:44:00 GMT

Well what you see are only active scanning packets while there can be (and probably are) many devices which just listen (so "whenever any central device tries to find BLE peripherals..." isn't true, it's rather "whenever some device actively requests additional advertising information from particular BLE peripheral"). From the poor description of failure I guess you expect to see MAC address or your "known" central but incoming SCAN_REQ packet is from another device. If you want to continue in this "blind" testing then either isolate your two devices (in some kind of Faraday cage or distant area with no BLE active devices) or change accept the fact that there will be such events from multiple devices and wait for your favorite peer.

RE: How to find if any Central Device is listening to Advertising data ?

nirmal@nordic — Tue, 29 Mar 2016 16:50:18 GMT

Thank you very much...

But I found that with setting scan_req_report option at enabling BLE , I can atleast receive BLE_GAP_SCAN_REQ_REPORT whenever any central device tries to find BLE peripherals in the range....That should do what I am looking for....

accoding to following link devzone.nordicsemi.com/.../

I tried it and It looks working but only problem is peer address found in the received scan Request report and Scanning device`s bluetooth address do not match.....

Please help me with this...

And explain me if I am wrong...

RE: How to find if any Central Device is listening to Advertising data ?

awneil — Tue, 29 Mar 2016 07:27:18 GMT

Or that BLE is the wrong solution

RE: How to find if any Central Device is listening to Advertising data ?

endnode — Mon, 28 Mar 2016 22:40:29 GMT

Hi. Awneil is right, you can hardly expect to detect "passive" listeners, physics is against you;) Latest Nordic Soft Devices support to detect "active" listeners when they issue Scan Request which follows one of Advertising packets issued by your GAP Broadcaster/Peripheral. However this assume that the other (GAP Central/Observer) device will issue them and that it will issue it at the moments you need. This you cannot influence even on Nordic stack right now so hard to take assumptions. If you believe that "detecting observer" is mandatory feature you need then it signals that your whole architecture is probably wrong...

Cheers Jan

RE: How to find if any Central Device is listening to Advertising data ?

awneil — Mon, 28 Mar 2016 21:37:06 GMT

No. But perhaps you could use Scan Request/Response; eg, see: