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iBeacon is an Apple technology based on BLE that you can use as an indoor positioning system. It allows iOS apps to track if the user enters a specific region and offers actions and notification aware of the user context.

The iBeacon class builds an advertising payload mimicking an iBeacon and assigns it to a given BLE interface.

Warning: To manufacture iBeacons, you must obtain a license from Apple. For more information, please see Apple's website. The licence also grants access to the iBeacon's technical specification.

iBeacon class reference

Data Structures
union  Payload
Public Types
typedef const uint8_t LocationUUID_t[16]
Public Member Functions
 iBeacon (BLE &_ble, LocationUUID_t uuid, uint16_t majNum, uint16_t minNum, uint8_t txP=0xC8, uint16_t compID=0x004C)
Protected Attributes
Payload data

iBeacon example

/* mbed Microcontroller Library
 * Copyright (c) 2006-2015 ARM Limited
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *     http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * See the License for the specific language governing permissions and
 * limitations under the License.

#include <events/mbed_events.h>
#include <mbed.h>
#include "ble/BLE.h"
#include "ble/services/iBeacon.h"

static iBeacon* ibeaconPtr;

static EventQueue eventQueue(/* event count */ 4 * EVENTS_EVENT_SIZE);

 * This function is called when the ble initialization process has failled
void onBleInitError(BLE &ble, ble_error_t error)
    /* Initialization error handling should go here */

void printMacAddress()
    /* Print out device MAC address to the console*/
    Gap::AddressType_t addr_type;
    Gap::Address_t address;
    BLE::Instance().gap().getAddress(&addr_type, address);
    printf("DEVICE MAC ADDRESS: ");
    for (int i = 5; i >= 1; i--){
        printf("%02x:", address[i]);
    printf("%02x\r\n", address[0]);

 * Callback triggered when the ble initialization process has finished
void bleInitComplete(BLE::InitializationCompleteCallbackContext *params)
    BLE&        ble   = params->ble;
    ble_error_t error = params->error;

    if (error != BLE_ERROR_NONE) {
        /* In case of error, forward the error handling to onBleInitError */
        onBleInitError(ble, error);

    /* Ensure that it is the default instance of BLE */
    if(ble.getInstanceID() != BLE::DEFAULT_INSTANCE) {

     * The Beacon payload has the following composition:
     * 128-Bit / 16byte UUID = E2 0A 39 F4 73 F5 4B C4 A1 2F 17 D1 AD 07 A9 61
     * Major/Minor  = 0x1122 / 0x3344
     * Tx Power     = 0xC8 = 200, 2's compliment is 256-200 = (-56dB)
     * Note: please remember to calibrate your beacons TX Power for more accurate results.
    static const uint8_t uuid[] = {0xE2, 0x0A, 0x39, 0xF4, 0x73, 0xF5, 0x4B, 0xC4,
                                   0xA1, 0x2F, 0x17, 0xD1, 0xAD, 0x07, 0xA9, 0x61};
    uint16_t majorNumber = 1122;
    uint16_t minorNumber = 3344;
    uint16_t txPower     = 0xC8;
    ibeaconPtr = new iBeacon(ble, uuid, majorNumber, minorNumber, txPower);

    ble.gap().setAdvertisingInterval(1000); /* 1000ms. */


void scheduleBleEventsProcessing(BLE::OnEventsToProcessCallbackContext* context) {
    BLE &ble = BLE::Instance();
    eventQueue.call(Callback<void()>(&ble, &BLE::processEvents));

int main()
    BLE &ble = BLE::Instance();


    return 0;

Note: You can find more information at the Apple iBeacon page.

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