BLE How to set the device name dynamically

RE: BLE How to set the device name dynamically

lcj — Thu, 25 Sep 2025 11:17:54 GMT

Ok. I resolved the -5 issue but still cannot change the name dynamically:

   LOG_DBG("Initializing BLE manager with name: %s", dynamic_name);

    int err;


    bt_addr_le_t addr;
	err = bt_addr_le_from_str("FF:EE:DD:CC:BB:AA", "random", &addr);
	if (err) {
		LOG_ERR("Invalid BT address (err %d)", err);
        return err;
	} else {
        LOG_DBG("BT address set");
    }


    err = bt_id_create(&addr, NULL);
	if (err < 0) {
		LOG_ERR("Creating new ID failed (err %d)", err);
        return err;
	} else {
        LOG_DBG("New ID created with index %d", err);
    }

    err = bt_enable(NULL);
    if (err) {
        LOG_ERR("Bluetooth init failed (err %d)", err);
        return err;
    } else {
        LOG_DBG("Bluetooth enabled");
    }

    // set the device name
    err = bt_set_name(dynamic_name);
    if (err) {
        LOG_ERR("Setting device name failed (err %d)", err);
        return err;
    } else {
        LOG_DBG("Device name set to %s", dynamic_name);
    }

    // set the advertising data
    err = bt_le_adv_update_data(ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));
    if (err) {
        LOG_ERR("Updating advertising data failed (err %d)", err);
        return err;
    } else {
        LOG_DBG("Advertising data updated");
    }


	k_work_init(&adv_work, adv_work_handler);
	advertising_start();

    return 0;

but I get this error in the log:

<dbg> ew_ble_manager: ew_ble_manager_init: Bluetooth enabled
<dbg> ew_ble_manager: ew_ble_manager_init: Device name set to TEST001
<err> ew_ble_manager: Updating advertising data failed (err -11)

if I comment out the bt_le_adv_update_data there is no error but the name does not change.

I have found this post as well [nRF Connect SDK] How to change BT name which seem to be recreating the sd rather than calling apis to change the name. But I can't do it exactly this way or the way I did it before because according to the latest DevAcademy lesson on Bluetooth LE Advertising (Lesson 2) for v3.1.1-v3.0.0 you need to do things a little differently because "Starting from version 3.0.0 of the nRF Connect SDK, advertising is automatically turned off when a peripheral connects to a central device, and it remains off after the disconnection."

Ok. Took away static const on ad and did this on top of all that:

    ad[1].data = dynamic_name;
	ad[1].data_len = strlen(dynamic_name);

Which works, but I don't understand what bt_set_name(dynamic_name); actually does here if I'm udating the array directly.

RE: BLE How to set the device name dynamically

Simonr — Wed, 24 Sep 2025 07:36:46 GMT

Hi Leo

Error message -5 points to an input/output error reported when trying to start the advertisement. Can you share the full log and your main.c file so I can take a better look at what is going on here? I assume you're still trying to set a dynamic device name when advertising.

Best regards,

Simon

RE: BLE How to set the device name dynamically

lcj — Mon, 22 Sep 2025 16:57:41 GMT

Now I'm getting a "Advertising failed to start (err -5)":

    const struct bt_data ad[] = {
        BT_DATA_BYTES(BT_DATA_FLAGS, BT_LE_AD_NO_BREDR),
        BT_DATA(BT_DATA_NAME_COMPLETE, dynamic_name, sizeof(dynamic_name)),
        BT_DATA(BT_DATA_MANUFACTURER_DATA, (unsigned char *)&adv_mfg_data, sizeof(adv_mfg_data)),
    };

This is frustrating.

RE: BLE How to set the device name dynamically

lcj — Wed, 04 Dec 2024 12:33:22 GMT

I was able to do it, but not as I expected. I was thinking I would be able to use bt_le_adv_update_data or bt_le_ext_adv_set_data and the bt_set_name() function, but that did not seem to work. I really don't know if it matters, but I was thinking there might be a simple example showing how they work.

By moving the bt_data into the main function, I was able to change the BT device name.

int ble_manager_init()
{
    LOG_DBG("Starting '%s'", DEVICE_NAME);

    int err;

    err = bt_enable(NULL);
    if (err) {
        LOG_ERR("Bluetooth init failed (err %d)", err);
        return -1;
    }
    LOG_DBG("Bluetooth initialized");

#ifdef CONFIG_BT_DEVICE_NAME_DYNAMIC

    // Generate a random 6-digit number
    unsigned int random_number = 100000 + rand() % 900000; // Ensures a range from 100000 to 999999
    LOG_DBG("Random number: %d", random_number);

    // Assuming random_number is already defined and holds a random 6-digit number
    char device_name[18]; // Ensure this is large enough to hold the resulting string
    
    // Create a formatted string with the random number
    snprintf(device_name, sizeof(device_name), "DeviceName %d", random_number);
    
    // Set the Bluetooth device name
    //bt_set_name(device_name);
    LOG_DBG("Bluetooth device name: %s", device_name);

    //bt_set_name(device_name);

    //param.options = BT_LE_ADV_OPT_USE_NAME;
    //bt_le_ext_adv_create(&param, NULL, &adv_set);
    //bt_le_per_adv_start(adv_set);

    //ad[1].data = device_name;
	//ad[1].data_len = strlen(device_name);

    /* didn't work
    err = bt_le_adv_update_data(ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));
    if (err) {
        LOG_ERR("Failed to update (err %d)", err);	
        return -1;
    }
    */


    struct bt_le_adv_param *adv_param = BT_LE_ADV_PARAM(
	(BT_LE_ADV_OPT_CONNECTABLE | BT_LE_ADV_OPT_USE_IDENTITY), /* Connectable advertising and use identity address */
	800, /* Min Advertising Interval 500ms (800*0.625ms) */
	801, /* Max Advertising Interval 500.625ms (801*0.625ms) */
	NULL); /* Set to NULL for undirected advertising */

    const struct bt_data ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, BT_LE_AD_NO_BREDR),
	BT_DATA(BT_DATA_NAME_COMPLETE, device_name, strlen(device_name)),
    /* STEP 3 - Include the Manufacturer Specific Data in the advertising packet. */
	BT_DATA(BT_DATA_MANUFACTURER_DATA, (unsigned char *)&adv_mfg_data, sizeof(adv_mfg_data)),
};


#endif

    err = bt_le_adv_start(adv_param, ad, ARRAY_SIZE(ad),sd, ARRAY_SIZE(sd));
    if (err) {
        LOG_ERR("Advertising failed to start (err %d)", err);	
        return -1;
    }

    LOG_DBG("Bluetooth advertising");

    return 0;
}

RE: BLE How to set the device name dynamically

lcj — Mon, 02 Dec 2024 14:27:18 GMT

Can you change/update it dynamically? Can you post the code?

RE: BLE How to set the device name dynamically

lara — Sat, 30 Nov 2024 10:13:32 GMT

i got it solved.adding

static char device_name[DEVICE_NAME_LEN] = "nRF52833_Device";

also in proj.conf

#
# Copyright (c) 2018 Nordic Semiconductor
#
# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
#
CONFIG_NCS_SAMPLES_DEFAULTS=y

CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME_DYNAMIC=y
#CONFIG_BT_DEVICE_NAME="NRF52833"

# Enable the LBS service
CONFIG_BT_LBS=y
CONFIG_BT_LBS_POLL_BUTTON=y
CONFIG_DK_LIBRARY=y

CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048

RE: BLE How to set the device name dynamically

lcj — Fri, 29 Nov 2024 16:21:12 GMT

I to switch to something else as I could not resolve this but need to get back to it. I was working on a simple example of how to change the name starting with the code above.

RE: BLE How to set the device name dynamically

lara — Fri, 29 Nov 2024 06:42:55 GMT

iam facing the same issue,have u got the solution? now u can change the name dynamically?

RE: BLE How to set the device name dynamically

Simonr — Tue, 13 Aug 2024 07:45:28 GMT

You need to update the device name by calling bt_le_adv_update_data or bt_le_ext_adv_set_data and the bt_set_name() inside there (with a constant character as the new name). In the code snippet you uploaded the bt_set_name() function is commented out.

/**
 * @brief Set Bluetooth Device Name
 *
 * Set Bluetooth GAP Device Name.
 *
 * When advertising with device name in the advertising data the name should
 * be updated by calling @ref bt_le_adv_update_data or
 * @ref bt_le_ext_adv_set_data.
 *
 * @note Requires @kconfig{CONFIG_BT_DEVICE_NAME_DYNAMIC}.
 *
 * @sa @kconfig{CONFIG_BT_DEVICE_NAME_MAX}.
 *
 * @param name New name
 *
 * @return Zero on success or (negative) error code otherwise.
 */
int bt_set_name(const char *name);

Best regards,

Simon

RE: BLE How to set the device name dynamically

lcj — Mon, 12 Aug 2024 16:13:40 GMT

How do I set the device name dynamically?

RE: BLE How to set the device name dynamically

Simonr — Mon, 12 Aug 2024 12:02:12 GMT

Hi Leo,

But you're adding these data members in read-only objects that won't be able to handle writable objects it seems.

Best regards,

Simon

RE: BLE How to set the device name dynamically

lcj — Fri, 09 Aug 2024 10:12:27 GMT

I don't think so. Same place I tried to set the name with bt_set_name, which seemed like it should work.

    // Generate a random 6-digit number
    unsigned int random_number = 100000 + rand() % 900000; // Ensures a range from 100000 to 999999
    LOG_DBG("Random number: %d", random_number);

    // Assuming random_number is already defined and holds a random 6-digit number
    char device_name[18]; // Ensure this is large enough to hold the resulting string
    
    // Create a formatted string with the random number
    snprintf(device_name, sizeof(device_name), "DeviceName %d", random_number);
    
    // Set the Bluetooth device name
    //bt_set_name(device_name);
    LOG_DBG("Bluetooth device name: %s", device_name);

    ad[1].data = device_name;
	ad[1].data_len = strlen(device_name);

    err = bt_le_adv_update_data(ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));
    if (err) {
        LOG_ERR("Failed to update (err %d)", err);	
        return -1;
    }

RE: BLE How to set the device name dynamically

Simonr — Wed, 31 Jul 2024 09:20:09 GMT

Where in your project are you adding these lines on your end? It seems like you're trying to assign them somewhere invalid...

Best regards,

Simon

RE: BLE How to set the device name dynamically

lcj — Tue, 30 Jul 2024 11:37:19 GMT

It didn't work. I got an error on the build.

error: assignment of member 'data' in read-only object
113 | ad[1].data = device_name;
| ^

error: assignment of member 'data_len' in read-only object
114 | ad[1].data_len = strlen(device_name);

RE: BLE How to set the device name dynamically

lcj — Tue, 30 Jul 2024 10:32:46 GMT

Ok. Yes. The uploaded .zip file has this:

	/* Start advertising  */
	char * ble_name = get_adv_name(); // Need to be called before bt_enable();
	ad[1].data = ble_name;
	ad[1].data_len = strlen(ble_name);
	LOG_INF( "BLE name: %s", nvs_store.ble_name);
	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), NULL, 0);
	if (err) {
		LOG_ERR("Advertising failed to start (err %d)", err);
		return -1;
	}

I will test and confirm. I guess I thought bt_set_name(device_name); was a way to do this.

RE: BLE How to set the device name dynamically

Simonr — Tue, 30 Jul 2024 08:35:37 GMT

Hi Leo

If you see in the last reply by Pedro, he uploaded a .zip file with code to "hopefully help someone". Did you check that out as well?

Best regards,

Simon

RE: BLE How to set the device name dynamically

lcj — Mon, 29 Jul 2024 10:28:17 GMT

There was no code in that to change the name. Only to store to store the changed name in flash. In the ticket Pedro says: "I have a BLE service which exposes the Device Name characteristic to allow user to change BLE name showed when advertising." which is what I want to do.

RE: BLE How to set the device name dynamically

Simonr — Mon, 29 Jul 2024 08:26:46 GMT

Okay, please check out this ticket by Sigurd, where he explains how you can use the NVS backend for storing the device name dynamically.

Best regards,

Simon

RE: BLE How to set the device name dynamically

lcj — Sat, 27 Jul 2024 01:44:09 GMT

2.6.1

RE: BLE How to set the device name dynamically

Simonr — Thu, 25 Jul 2024 13:36:52 GMT

First off, what SDK version are you using here. I just want to make sure we start on the same page here. It might seem like either the Bluetooth stack isn't initialized yet or that the advertiser is busy with something, since the error message basically means "try again", and doesn't point to anything specific.

Best regards,

Simon

RE: BLE How to set the device name dynamically

lcj — Wed, 24 Jul 2024 11:16:36 GMT

I did turn Bluetooth on and off.

I tried adding:

// Set the Bluetooth device name
bt_set_name(device_name);
LOG_DBG("Bluetooth device name: %s", device_name);

err = bt_le_adv_update_data(ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));
if (err) {
    LOG_ERR("Failed to update (err %d)", err);
    return -1;
}

and got:

[00:00:00.470,611] <err> ble_manager: Failed to update (err -11)

but I don't know why I would need to update the data if I'm setting the name before I start advertising. I guess that's my question. What is the right order of methods to call in order to set the name dynamically.

RE: BLE How to set the device name dynamically

Simonr — Wed, 24 Jul 2024 08:38:40 GMT

In the second link you provided, Einar explains that most scanners/phones will cache the device name, so in most cases you need to toggle Bluetooth on/off on the scanner side to update a name on the scanner. If you've already done that, you should make sure that the name is updated in the advertising packet with bt_le_adv_update_data() which I don't see you're using.

Best regards,

Simon