How to read advertising BLE devices' name?

RE: How to read advertising BLE devices' name?

caoliyu1086 — Thu, 19 Oct 2023 08:16:22 GMT

thx，i create a new ticket for it now

RE: How to read advertising BLE devices' name?

runsiv — Thu, 19 Oct 2023 05:56:31 GMT

Hi,

In order to keep things clean, could you kindly create a new ticket with your issue and also include which SDK and device you are using?
Regards

Runar

RE: How to read advertising BLE devices' name?

caoliyu1086 — Thu, 19 Oct 2023 01:49:18 GMT

in "device_found()" callback: I can only get the type: 0x01 0x06 0xFF, and the 0xFF 0x09 after this can't get

RE: How to read advertising BLE devices' name?

caoliyu1086 — Thu, 19 Oct 2023 01:45:41 GMT

I get the same problem when I want to get the BLE devices' name

the "BLE Central" can only get 31-Bytes adv data in "device_found()" callback, but the device-name need more than 31-Bytes

in "nRF Connect" I get the BLE-device like this:

but in the "BLE Central" example, can only get 31-Bytes adv data like this:

How can i get more than 31-Bytes adv data in "device_found()" callback?

RE: How to read advertising BLE devices' name?

runsiv — Mon, 24 Apr 2023 12:29:01 GMT

Hi,

Neither "peripheral" or "peripheral_uart" includes any code that changes the transmission gain rom what I can see, so they should be similar.

As for the code snippet

if (rssi < -70) {
		return;
	}

Its only for connecting to a device. The data from the advertisement package should be readable without connecting to the device. So the filter should not have any effect on the readout that happens before any connection.

When you say without any modifications: Did you remove the parsing of the advertisement data to extract the device name?

Regards

Runar

RE: How to read advertising BLE devices' name?

Bk37 — Fri, 21 Apr 2023 18:51:36 GMT

I am working with a clean 'central' and clean 'peripheral' example, except the changes you suggested.

I believe I found the cause of the issue, maybe you could explain why it's happening.

In the 'central' sketch, in 'device_found()' there's a filter for proximity:

if (rssi < -70) {
		return;
	}

When I changed '-70' to '-50', this fixed the issue, however, I'm confused as to why, since the average RSSI for that device is -60, and often times around -40 to -50, but when the filter is set to -70, it NEVER reports the peripheral device name (even though it DOES find the MAC address).

Even more confusing is why the signal strength is different for the 'peripheral' and 'peripheral_uart' examples when they're performed on the exact same device?

RE: How to read advertising BLE devices' name?

runsiv — Fri, 21 Apr 2023 07:38:54 GMT

Hi, can you please upload your projects. I tested with the peripheral example and central example and I had no problems finding the peripheral device.

Regards

Runar

RE: How to read advertising BLE devices' name?

Bk37 — Fri, 21 Apr 2023 06:29:07 GMT

Just tried this, but no change to the result.

"peripheral_uart" to "central" shows the name.

"peripheral" to "central" does not show the name.

RE: How to read advertising BLE devices' name?

runsiv — Fri, 21 Apr 2023 06:07:38 GMT

Hi,

Can you try to change "start_scan" to:

err = bt_le_scan_start(BT_LE_SCAN_PASSIVE, device_found);

to

err = bt_le_scan_start(BT_LE_SCAN_ACTIVE, device_found);

and

add update device_found with this:

	if (type != BT_GAP_ADV_TYPE_ADV_IND &&
	    type != BT_GAP_ADV_TYPE_ADV_DIRECT_IND &&
		type != BT_GAP_ADV_TYPE_SCAN_RSP  ) {
		return;
	}

Regards

Runar

RE: How to read advertising BLE devices' name?

Bk37 — Thu, 20 Apr 2023 14:28:22 GMT

[quote userid="122502" url="~/f/nordic-q-a/98754/how-to-read-advertising-ble-devices-name/421495"]Do you advertise device name from your peripheral? [/quote]

Yes, but also so do the other devices around me.

I tried with a brand new project, totally clean, same issue.

Device found: C6:65:16:45:84:67 (public) (RSSI -75)
Device found:
Connected: C6:65:16:45:84:67 (public)
Disconnected: C6:65:16:45:84:67 (reason 0x3e)
Scanning successfully started

After uploading the "peripheral_uart" example to the peripheral device, the name now DOES show up in the terminal on the central device DK. However, other devices still do not, including the "peripheral" (without uart) example.

Why is that? I want to use the "peripheral" example, not the "peripheral_uart". What is causing this issue?

RE: How to read advertising BLE devices' name?

runsiv — Thu, 20 Apr 2023 12:30:25 GMT

Do you advertise device name from your peripheral? I tested with the peripheral_uart example and I could find it without any problems using the code I have you,

Regards

Runar

RE: How to read advertising BLE devices' name?

Bk37 — Wed, 19 Apr 2023 14:35:56 GMT

[quote userid="122502" url="~/f/nordic-q-a/98754/how-to-read-advertising-ble-devices-name/421149"]You could not find any names at all? [/quote]

None, and there are at least 4 bluetooth devices advertising their name nearby.

[quote userid="122502" url="~/f/nordic-q-a/98754/how-to-read-advertising-ble-devices-name/421149"]do you have another dk you can set up as an peripheral? [/quote]

My central device is an nRF52840 DK, and I've been using an nRF52840 MDK Dongle as a peripheral.

In case this helps, here's what the prj.conf and CMakeLists.txt files look like:

CONFIG_BT=y
CONFIG_BT_CENTRAL=y

# SPDX-License-Identifier: Apache-2.0

cmake_minimum_required(VERSION 3.20.0)
find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
project(central)

target_sources(app PRIVATE
  src/main.c
)

zephyr_library_include_directories(${ZEPHYR_BASE}/samples/bluetooth)

RE: How to read advertising BLE devices' name?

runsiv — Wed, 19 Apr 2023 06:18:41 GMT

Interesting, I will see if I can replicate it. You could not find any names at all?

Also, do you have another dk you can set up as an peripheral?

Regards

Runar

RE: How to read advertising BLE devices' name?

Bk37 — Wed, 19 Apr 2023 02:28:12 GMT

Thanks for the reply. I added this code, but I'm still not getting anything.

The terminal says "Device Found: ", but does not actually list a name. However, the available devices definitely do have friendly names, as proven by my iPhone.

Scanning successfully started
Device Found: xx:xx:xx:xx:xx:x1 (random) (RSSI -79)
Device Found:
Device Found: xx:xx:xx:xx:xx:x2 (random) (RSSI -82)
Device Found:
Device Found: xx:xx:xx:xx:xx:x3 (random) (RSSI -60)
Device Found:
Connected: xx:xx:xx:xx:xx:x3 (public)
Disconnected: xx:xx:xx:xx:xx:x3 (public) (reason 0x3e)

Here are the functions after I've edited them:

static bool data_cb(struct bt_data *data, void *user_data){

	char *name = user_data;

	switch(data->type){
		case BT_DATA_NAME_SHORTENED:
		case BT_DATA_NAME_COMPLETE:
			memcpy(name, data->data, MIN(data->data_len, NAME_LEN - 1));
			return false;
		default:
			return false;
	}
}

static void device_found(const bt_addr_le_t *addr, int8_t rssi, uint8_t type,
			 struct net_buf_simple *ad)
{
	char addr_str[BT_ADDR_LE_STR_LEN];
	char name[30];
	int err;

	if (default_conn) {
		return;
	}

	/* We're only interested in connectable events */
	if (type != BT_GAP_ADV_TYPE_ADV_IND &&
	    type != BT_GAP_ADV_TYPE_ADV_DIRECT_IND) {
		return;
	}

	bt_addr_le_to_str(addr, addr_str, sizeof(addr_str));
	printk("Device found: %s (RSSI %d)\n", addr_str, rssi);

	//setting up the bt_data_parse function and prints it.
	bt_data_parse(ad, data_cb, name);
	printk("Device found: %s \n", name);

	/* connect only to devices in close proximity */
	if (rssi < -70) {
		return;
	}

	if (bt_le_scan_stop()) {
		return;
	}

	err = bt_conn_le_create(addr, BT_CONN_LE_CREATE_CONN,
				BT_LE_CONN_PARAM_DEFAULT, &default_conn);
	if (err) {
		printk("Create conn to %s failed (%u)\n", addr_str, err);
		start_scan();
	}
}

In the switch-case statement in the 'data_cb' function, it is triggering 'default', not 'BT_DATA_NAME_SHORTENED' or 'BT_DATA_NAME_COMPLETE'.

RE: How to read advertising BLE devices' name?

runsiv — Tue, 18 Apr 2023 12:52:27 GMT

Hi.

If you use the bt_central example I you can add the following lines and functions to print out the device names:

Updated device found function:

static void device_found(const bt_addr_le_t *addr, int8_t rssi, uint8_t type,
			 struct net_buf_simple *ad)
{
	char addr_str[BT_ADDR_LE_STR_LEN];
	char name[30];
	int err;

	if (default_conn) {
		return;
	}

	/* We're only interested in connectable events */
	if (type != BT_GAP_ADV_TYPE_ADV_IND &&
	    type != BT_GAP_ADV_TYPE_ADV_DIRECT_IND) {
		return;
	}

	bt_addr_le_to_str(addr, addr_str, sizeof(addr_str));
	printk("Device found: %s (RSSI %d)\n", addr_str, rssi);

	//seting up the bt_data_parse function and prints it. 
	//
	bt_data_parse(ad, data_cb, name);
	printk("Device found: %s \n", name);

	/* connect only to devices in close proximity */
	if (rssi < -70) {
		return;
	}

	if (bt_le_scan_stop()) {
		return;
	}

	err = bt_conn_le_create(addr, BT_CONN_LE_CREATE_CONN,
				BT_LE_CONN_PARAM_DEFAULT, &default_conn);
	if (err) {
		printk("Create conn to %s failed (%u)\n", addr_str, err);
		start_scan();
	}
}

Added function data_cb

#define NAME_LEN 30

static bool data_cb(struct bt_data *data, void *user_data)
{
	char *name = user_data;

	switch (data->type) {
	case BT_DATA_NAME_SHORTENED:
	case BT_DATA_NAME_COMPLETE:
		memcpy(name, data->data, MIN(data->data_len, NAME_LEN - 1));
		return false;
	default:
		return true;
	}
}

Now your central will print out the name of the devices found during scanning.

Regards

Runar

RE: How to read advertising BLE devices' name?

runsiv — Tue, 18 Apr 2023 07:47:04 GMT

Hi,

I'm working on making an example on this. In short what needs to be done is to decode the advertisement package data and extract the name from there. The function bt_data_parse is used to parse the advertising data. The device name may not be broadcasted from all devices, this depends on the settings for the advertainment on the peripheral device.

Regards

Runar

RE: How to read advertising BLE devices' name?

runsiv — Mon, 17 Apr 2023 12:02:18 GMT

I'm looking into it and will get back to you tomorrow

Regards

Runar