A peripheral that scans for nonconnectable advertisements to get data

[brianreinhold]

I thought this would be rather simple as I would design a BLE peripheral in the usual way but the source of data for the peripheral comes from a sensor sending nonconnectable advertisements.

The logical approach seemed to be 

• start advertising
• wait for a connection event and then start a scanner
• in the received advertisement callback, place the packet in a queue
• read the queue and convert the data to the appropriate measurement characteristic expected by the central I am connected with
• notify the data

However, when looking at the sd_ble_gap_scan_start documentation for s140 it is unclear to me what it can do. I have the following questions/uncertainties:

1. The method seems strongly coupled to the sd_ble_gap_connect method which I have no intention to use. What are the consequences of that?
2. I cannot use addresses as filters or whitelists but I could have used manufacturer data if such a filter existed. So I assume there is no hardware filtering on this scanner and I will need to do it myself in the advertisement callback - if there is a more efficient means of filtering out unwanted advertisements that would be nice (like non-connectable only)
3. I am not even sure the method will pass up non-connectable advertisements - there is no mention of them in the documentation.
4. Will the fact I have configured SoftDevice as a peripheral make it impossible to scan in the first place? How can I be both an Observer and a peripheral? (Note observer here is not the 'observer' mentioned in the Nordic SDK - I don't know what those observers are. Observer here is the BTLE watcher of broadcasts.)
5. What kind of conflict will arise by scanning at the same time as being connected - can I run the scanner at 'full throttle'?

Thanks

[awneil]

Your device will have to implement both Peripheral and Central roles:

• Peripheral for the connection;
• Central for the scanning.

There are BLE Central+Peripheral examples in the SDK ...

[brianreinhold]

There is a difference between Central and Observer. It is not clear to me how to do that via SoftDevice calls. How about the other issues #1, #2, #3, and #5?

[awneil]

brianreinhold said:

There is a difference between Central and Observer

Yes  - A BLE Observer just does the scanning; never connects.

I don't think that Nordic have a separate SoftDevice for just Observer - you just use a Central one for the scanning, but never go on to connect. Similarly there isn't a separate Beacon SD  - you just use a Peripheral one for the advertising, but never go on to connect.

"Observer" in SDK terms is a "hook" which "observes" SoftDevice events

[brianreinhold]

Thanks, but I'd still like some answers or documentation for questions/issues #1, #2, #3, and #5!