[Bluetooth] filter name

RE: [Bluetooth] filter name

seongmincho — Thu, 11 Jul 2024 05:42:51 GMT

Can you try setting CONFIG_BT_SCAN_NAME_CNT to 3?

RE: [Bluetooth] filter name

Mihaela — Wed, 10 Jul 2024 13:52:08 GMT

Hi,

I also had a similar problem as explained here.
I am referring to this: However, even though DEVICE_NAME(peripheral: "SEONG") and FILTER(central: "SEONGMIN") are not exactly the same, they still get connected.

The same thing happens to me. I am using BT_SCAN_FILTER_TYPE_NAME and expecting that the peripheral device will connect only if the full name is matched with the filter.

However, I have a case where the filter on the central device is set to "PRI", but it will connect to the device that is advertising only "P", so DEVICE_NAME(peripheral: "P") and FILTER(central: "PRI") connect. Why is the behavior like this, and is there a way to avoid it?

The configuration is similar to the one pasted above, with difference in the two configs:

CONFIG_BT_SCAN_UUID_CNT=0
CONFIG_BT_SCAN_NAME_CNT=1

BR,

Mihaela

RE: [Bluetooth] filter name

tesc — Tue, 09 Jul 2024 14:34:51 GMT

Hi,

The (full) name (BT_SCAN_FILTER_TYPE_NAME) sets up a filter scanning for full name advertisements.

This means for instance if the name of the device you are looking for is "MyDevice" and the full name fits in the advertising packet, a filter on "MyDevice" as full name will match the device. If however the device does not have enough space in the advertisement to advertise the full name, and instead it advertises only a short name, then you will not get a match.

The short name (BT_SCAN_FILTER_TYPE_SHORT_NAME) sets up a filter scanning for short name advertisements.

This means for instance if the name of the device you are looking for is "MyDevice" and it is advertised as "MyDev" due to that being the available space for advertising a short name in the advertising packet, and the minimum setting for short name length is 5 or higher, then you will get a match.

Continuing hte same example, if on the other hand you find a device with short name of "MyDevv", you will not get a match, since the beginning of the short name does not match perfectly with what was registered as the device name you were looking for. Likewise, you will not get a match which is too short.

Regards,
Terje

RE: [Bluetooth] filter name

seongmincho — Tue, 09 Jul 2024 01:23:15 GMT

are you there..?

RE: [Bluetooth] filter name

seongmincho — Tue, 02 Jul 2024 05:10:52 GMT

can you explain the exact difference between the 'short name'(BT_SCAN_FILTER_TYPE_SHORT_NAME) and the 'name'(BT_SCAN_FILTER_TYPE_NAME) in filter type?

RE: [Bluetooth] filter name

tesc — Mon, 01 Jul 2024 16:36:36 GMT

Hi,

Filtering is based on the contents of the advertisements. For long device names, typically a shortened name is used. This can be either a predefined name, or is done automatically by shortening the full device name by removing characters from the end.

What might happen in this instance, is if the full name is SEONGMIN, it may, depending on the size available in the advertising package, be shortened to for instance "SEONG" as a short name for the advertising.

You can for instance use the nRF Connect for Desktop BLE app, or one of the nRF Connect for smartphone apps, to investigate what contents (including name) appears in the advertising packet for the peripheral device.

Regards,
Terje