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iBeacon

Note: This class has been deprecated.

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 license also grants access to the iBeacon's technical specification.

iBeacon class reference

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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * 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 "pretty_printer.h"

static events::EventQueue event_queue(/* event count */ 16 * EVENTS_EVENT_SIZE);

/** @deprecated This demo is deprecated and no replacement is currently available.
 */
MBED_DEPRECATED_SINCE(
   "mbed-os-5.11",
   "This demo is deprecated and no replacement is currently available."
)
class BeaconDemo : ble::Gap::EventHandler {
public:
    BeaconDemo(BLE &ble, events::EventQueue &event_queue) :
        _ble(ble),
        _event_queue(event_queue),
        _adv_data_builder(_adv_buffer) { }

    void start() {
        _ble.gap().setEventHandler(this);

        _ble.init(this, &BeaconDemo::on_init_complete);

        _event_queue.dispatch_forever();
    }

private:
    /**
     * iBeacon payload builder.
     *
     * This data structure contains the payload of an iBeacon. The payload is
     * built at construction time and application code can set up an iBeacon by
     * injecting the raw field into the GAP advertising payload as a
     * GapAdvertisingData::MANUFACTURER_SPECIFIC_DATA.
     */
    union Payload {
        /**
         * Raw data of the payload.
         */
        uint8_t raw[25];
        struct {
            /**
             * Beacon manufacturer identifier.
             */
            uint16_t companyID;

            /**
             * Packet ID; Equal to 2 for an iBeacon.
             */
            uint8_t ID;

            /**
             * Length of the remaining data presents in the payload.
             */
            uint8_t len;

            /**
             * Beacon UUID.
             */
            uint8_t proximityUUID[16];

            /**
             * Beacon Major group ID.
             */
            uint16_t majorNumber;

            /**
             * Beacon minor ID.
             */
            uint16_t minorNumber;

            /**
             * Tx power received at 1 meter; in dBm.
             */
            uint8_t txPower;
        };

        /**
         * Assemble an iBeacon payload.
         *
         * @param[in] uuid Beacon network ID. iBeacon operators use this value
         * to group their iBeacons into a single network, a single region and
         * identify their organization among others.
         *
         * @param[in] majNum Beacon major group ID. iBeacon exploitants may use
         * this field to divide the region into subregions, their network into
         * subnetworks.
         *
         * @param[in] minNum Identifier of the Beacon in its subregion.
         *
         * @param[in] transmitPower Measured transmit power of the beacon at 1
         * meter. Scanners use this parameter to approximate the distance
         * to the beacon.
         *
         * @param[in] companyIDIn ID of the beacon manufacturer.
         */
        Payload(
            const uint8_t *uuid,
            uint16_t majNum,
            uint16_t minNum,
            uint8_t transmitPower,
            uint16_t companyIDIn
        ) : companyID(companyIDIn),
            ID(0x02),
            len(0x15),
            majorNumber(__REV16(majNum)),
            minorNumber(__REV16(minNum)),
            txPower(transmitPower)
        {
            memcpy(proximityUUID, uuid, 16);
        }
    };

    /** Callback triggered when the ble initialization process has finished */
    void on_init_complete(BLE::InitializationCompleteCallbackContext *params) {
        if (params->error != BLE_ERROR_NONE) {
            printf("Ble initialization failed.");
            return;
        }

        print_mac_address();

        start_advertising();
    }

    void start_advertising() {
        /* Create advertising parameters and payload */

        ble::AdvertisingParameters adv_parameters(
            ble::advertising_type_t::CONNECTABLE_UNDIRECTED,
            ble::adv_interval_t(ble::millisecond_t(1000))
        );

        _adv_data_builder.setFlags();

        /**
         * 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 major_number = 1122;
        uint16_t minor_number = 3344;
        uint16_t tx_power     = 0xC8;
        uint16_t comp_id      = 0x004C;

        Payload ibeacon(uuid, major_number, minor_number, tx_power, comp_id);

        _adv_data_builder.setManufacturerSpecificData(ibeacon.raw);

        /* Setup advertising */

        ble_error_t error = _ble.gap().setAdvertisingParameters(
            ble::LEGACY_ADVERTISING_HANDLE,
            adv_parameters
        );

        if (error) {
            print_error(error, "_ble.gap().setAdvertisingParameters() failed");
            return;
        }

        error = _ble.gap().setAdvertisingPayload(
            ble::LEGACY_ADVERTISING_HANDLE,
            _adv_data_builder.getAdvertisingData()
        );

        if (error) {
            print_error(error, "_ble.gap().setAdvertisingPayload() failed");
            return;
        }

        /* Start advertising */

        error = _ble.gap().startAdvertising(ble::LEGACY_ADVERTISING_HANDLE);

        if (error) {
            print_error(error, "_ble.gap().startAdvertising() failed");
            return;
        }
    }

private:
    /* Event handler */

    void onDisconnectionComplete(const ble::DisconnectionCompleteEvent&) {
        _ble.gap().startAdvertising(ble::LEGACY_ADVERTISING_HANDLE);
    }

private:
    BLE &_ble;
    events::EventQueue &_event_queue;

    uint8_t _adv_buffer[ble::LEGACY_ADVERTISING_MAX_SIZE];
    ble::AdvertisingDataBuilder _adv_data_builder;
};

/** Schedule processing of events from the BLE middleware in the event queue. */
void schedule_ble_events(BLE::OnEventsToProcessCallbackContext *context) {
    event_queue.call(Callback<void()>(&context->ble, &BLE::processEvents));
}

int main()
{
    BLE &ble = BLE::Instance();
    ble.onEventsToProcess(schedule_ble_events);

    BeaconDemo demo(ble, event_queue);
    demo.start();

    return 0;
}

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

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