main.cpp

/* 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 "ble/gap/Gap.h"
#include "ble/gap/AdvertisingDataParser.h"
#include "platform/CircularBuffer.h"

#define BUF_SIZE    20

static EventQueue event_queue(/* event count */ 20 * EVENTS_EVENT_SIZE);

class LEDBlinkerDemo : ble::Gap::EventHandler {
public:
    LEDBlinkerDemo(BLE &ble, events::EventQueue &event_queue) :
        _ble(ble),
        _event_queue(event_queue),
        _alive_led(LED1, 1),
        _actuated_led(LED2, 0) { }

    ~LEDBlinkerDemo() { }

    void start() {
        _ble.gap().setEventHandler(this);
        _ble.init(this, &LEDBlinkerDemo::on_init_complete);
        _event_queue.call_every(10000, this, &LEDBlinkerDemo::send_recent_beacons);
        _event_queue.dispatch_forever();
    }

private:
    /** 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();
        ble::ScanParameters scan_params;
        scan_params.set1mPhyConfiguration(ble::scan_interval_t(5000), ble::scan_window_t(1000), false);
        _ble.gap().setScanParameters(scan_params);
        _ble.gap().startScan();
    }

    void send_recent_beacons() {
        _alive_led = !_alive_led;

        beacon data;
        printf("\n\n-----------------------------\n");
        printf ("Beacons: \n");
        int i = 1;
        while (!buf.empty()) {
            buf.pop(data);
            printf("%02d. ", i);
            print_address(data.addr.data());
            printf(" rssi: %d \n", data.rssi);
            i++;
        }
        printf("-----------------------------\n\n");
    }


private:
    /** print device address to the terminal */
    void print_address(const uint8_t *addr)
    {
        printf("%02x:%02x:%02x:%02x:%02x:%02x",
               addr[5], addr[4], addr[3], addr[2], addr[1], addr[0]);
    }

    void onAdvertisingReport(const ble::AdvertisingReportEvent &event) {
        //if (event.getRssi() < -40) continue; 
        _actuated_led = false;
        print_address(event.getPeerAddress().data());
        printf(" rssi: %d\r\n", event.getRssi());
        beacon b {event.getPeerAddress(), event.getRssi()};
        buf.push(b);
        _actuated_led = true;

    }

private:
    struct beacon {
        ble::address_t addr;
        ble::rssi_t rssi;
    };
    BLE &_ble;
    events::EventQueue &_event_queue;
    DigitalOut _alive_led;
    DigitalOut _actuated_led;
    CircularBuffer<beacon, BUF_SIZE> buf;
};

/** 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);

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

    return 0;
}

Install instructions for Ubuntu 19.10:

sudo apt install python3-dev python3-venv git gcc-arm-none-eabi gcc wget
mkdir mbedos
cd mbedos/
python3 -m venv venv/         # set up virtual environment
source venv/bin/activate      # activate virtual environment
pip install mbed-cli
mbed config -G target NRF52_DL
mbed config -G toolchain GCC_ARM
mbed import https://github.com/ARMmbed/mbed-os-example-blinky   # takes awhile (it's downloading mbed-os)
cd mbed-os-example-blinky
mv main.cpp main.cpp.orig
wget https://gist.github.com/pipitone/6dfb549d1daf345194c08ed182e3ef89/raw/29579c16fb3b7af046befd83fb4b6ee32f4edb71/main.cpp
mbed compile