This application transmits a heart rate value using the Bluetooth SIG Heart Rate Profile. The heart rate value is provided by the application itself, not by a sensor, so that you don't have to get a sensor just to run the example. The canonical source for this example lives at https://github.com/ARMmbed/mbed-os-example-ble/tree/master/BLE_HeartRate

BLE Heart Rate Monitor

This application transmits a heart rate value using the Bluetooth SIG Heart Rate Profile. The heart rate value is provided by the application itself, not by a sensor, so that you don't have to get a sensor just to run the example.

Technical details are better presented in the mbed Classic equivalent of this example.

Running the application

Requirements

To see the heart rate information on your phone, download Panobike for iOS or Android.

You could also use a generic BLE scanners:

- nRF Master Control Panel for Android.

- LightBlue for iPhone.

Hardware requirements are in the main readme.

Building instructions

Building with mbed-cli

If you'd like to use mbed-cli to build this, then you should refer to the main readme. The instructions here relate to using the developer.mbed.org Online Compiler

In order to build this example in the mbed Online Compiler, first import the example using the ‘Import’ button on the right hand side.

Next, select a platform to build for. This must either be a platform that supports BLE, for example the NRF51-DK, or one of the following:

List of platforms supporting Bluetooth Low Energy

Or you must also add a piece of hardware and the supporting library that includes a Bluetooth Low Energy driver for that hardware, for example the K64F or NUCLEO_F401RE with the X-NUCLEO-IDB05A1

List of components supporting Bluetooth Low Energy.

Once you have selected your platform, compile the example and drag and drop the resulting binary onto your board.

For general instructions on using the mbed Online Compiler, please see the mbed Handbook

Checking for success

Note: Screens captures depicted below show what is expected from this example if the scanner used is nRF Master Control Panel version 4.0.5. If you encounter any difficulties consider trying another scanner or another version of nRF Master Control Panel. Alternative scanners may require reference to their manuals.

  • Build the application and install it on your board as explained in the building instructions.
  • Open the BLE scanner on your phone.
  • Start a scan.

/media/uploads/vcoubard/start_scan.png

figure 1 How to start scan using nRF Master Control Panel 4.0.5

  • Find your device; it should be named `HRM`.

/media/uploads/vcoubard/scan_result.png

figure 2 Scan results using nRF Master Control Panel 4.0.5

  • Establish a connection with your device.

/media/uploads/vcoubard/connection.png

figure 3 How to establish a connection using Master Control Panel 4.0.5

  • Discover the services and the characteristics on the device. The *Heart Rate* service has the UUID `0x180D` and includes the *Heart Rate Measurement* characteristic which has the UUID `0x2A37`.

/media/uploads/vcoubard/discovery.png

figure 4 Representation of the Heart Rate service using Master Control Panel 4.0.5

  • Register for the notifications sent by the Heart Rate Measurement characteristic.

/media/uploads/vcoubard/register_to_notifications.png

figure 5 How to register to notifications using Master Control Panel 4.0.5

  • You should see the heart rate value change every half second. It begins at 100, goes up to 175 (in steps of 1), resets to 100 and so on.

/media/uploads/vcoubard/notifications.png

figure 6 Notifications view using Master Control Panel 4.0.5

Files at this revision

API Documentation at this revision

Comitter:
mbed_official
Date:
Mon Jan 14 10:45:44 2019 +0000
Parent:
72:584fc328cad6
Child:
74:74c41613796b
Commit message:
Merge pull request #208 from ARMmbed/mbed-os-5.11.0-oob

Mbed OS 5.11.0
.
Commit copied from https://github.com/ARMmbed/mbed-os-example-ble

Changed in this revision

mbed-os.lib Show annotated file Show diff for this revision Revisions of this file
mbed_app.json Show annotated file Show diff for this revision Revisions of this file
shields/TARGET_CORDIO_BLUENRG.lib Show annotated file Show diff for this revision Revisions of this file
source/main.cpp Show annotated file Show diff for this revision Revisions of this file
source/pretty_printer.h Show annotated file Show diff for this revision Revisions of this file
--- a/mbed-os.lib	Fri Dec 14 13:15:37 2018 +0000
+++ b/mbed-os.lib	Mon Jan 14 10:45:44 2019 +0000
@@ -1,1 +1,1 @@
-https://github.com/ARMmbed/mbed-os/#2fd0c5cfbd83fce62da6308f9d64c0ab64e1f0d6
+https://github.com/ARMmbed/mbed-os/#6a0a86538c0b9b2bfcc4583b1e2b7fea8f4e71e9
--- a/mbed_app.json	Fri Dec 14 13:15:37 2018 +0000
+++ b/mbed_app.json	Mon Jan 14 10:45:44 2019 +0000
@@ -11,6 +11,16 @@
         "DISCO_L475VG_IOT01A": {
             "target.features_add": ["BLE"],
             "target.extra_labels_add": ["CORDIO", "CORDIO_BLUENRG"]
+        },
+        "NRF52840_DK": {
+            "target.features_add": ["BLE"],
+            "target.extra_labels_add": ["CORDIO", "CORDIO_LL", "SOFTDEVICE_NONE", "NORDIC_CORDIO"],
+            "target.extra_labels_remove": ["SOFTDEVICE_COMMON", "SOFTDEVICE_S140_FULL", "NORDIC_SOFTDEVICE"]
+        },
+        "NRF52_DK": {
+            "target.features_add": ["BLE"],
+            "target.extra_labels_add": ["CORDIO", "CORDIO_LL", "SOFTDEVICE_NONE", "NORDIC_CORDIO"],
+            "target.extra_labels_remove": ["SOFTDEVICE_COMMON", "SOFTDEVICE_S132_FULL", "NORDIC_SOFTDEVICE"]
         }
     }
 }
--- a/shields/TARGET_CORDIO_BLUENRG.lib	Fri Dec 14 13:15:37 2018 +0000
+++ b/shields/TARGET_CORDIO_BLUENRG.lib	Mon Jan 14 10:45:44 2019 +0000
@@ -1,1 +1,1 @@
-https://github.com/ARMmbed/cordio-ble-x-nucleo-idb0xa1/#51f60dfea514e35e5aa13c8e24005ecadc24a9f5
+https://github.com/ARMmbed/cordio-ble-x-nucleo-idb0xa1/#811f3fea7aa8083c0bbf378e1b51a8b131d7efcc
--- a/source/main.cpp	Fri Dec 14 13:15:37 2018 +0000
+++ b/source/main.cpp	Mon Jan 14 10:45:44 2019 +0000
@@ -17,111 +17,157 @@
 #include <events/mbed_events.h>
 #include <mbed.h>
 #include "ble/BLE.h"
-#include "ble/Gap.h"
+#include "ble/gap/Gap.h"
 #include "ble/services/HeartRateService.h"
+#include "pretty_printer.h"
 
-DigitalOut led1(LED1, 1);
+const static char DEVICE_NAME[] = "Heartrate";
+
+static events::EventQueue event_queue(/* event count */ 16 * EVENTS_EVENT_SIZE);
 
-const static char     DEVICE_NAME[] = "HRM";
-static const uint16_t uuid16_list[] = {GattService::UUID_HEART_RATE_SERVICE};
-
-static uint8_t hrmCounter = 100; // init HRM to 100bps
-static HeartRateService *hrServicePtr;
-
-static EventQueue eventQueue(/* event count */ 16 * EVENTS_EVENT_SIZE);
+class HeartrateDemo : ble::Gap::EventHandler {
+public:
+    HeartrateDemo(BLE &ble, events::EventQueue &event_queue) :
+        _ble(ble),
+        _event_queue(event_queue),
+        _led1(LED1, 1),
+        _connected(false),
+        _hr_uuid(GattService::UUID_HEART_RATE_SERVICE),
+        _hr_counter(100),
+        _hr_service(ble, _hr_counter, HeartRateService::LOCATION_FINGER),
+        _adv_data_builder(_adv_buffer) { }
 
-void disconnectionCallback(const Gap::DisconnectionCallbackParams_t *params)
-{
-    BLE::Instance().gap().startAdvertising(); // restart advertising
-}
+    void start() {
+        _ble.gap().setEventHandler(this);
+
+        _ble.init(this, &HeartrateDemo::on_init_complete);
+
+        _event_queue.call_every(500, this, &HeartrateDemo::blink);
+        _event_queue.call_every(1000, this, &HeartrateDemo::update_sensor_value);
+
+        _event_queue.dispatch_forever();
+    }
 
-void updateSensorValue() {
-    // Do blocking calls or whatever is necessary for sensor polling.
-    // In our case, we simply update the HRM measurement.
-    hrmCounter++;
+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;
+        }
 
-    //  100 <= HRM bps <=175
-    if (hrmCounter == 175) {
-        hrmCounter = 100;
+        print_mac_address();
+
+        start_advertising();
     }
 
-    hrServicePtr->updateHeartRate(hrmCounter);
-}
+    void start_advertising() {
+        /* Create advertising parameters and payload */
 
-void periodicCallback(void)
-{
-    led1 = !led1; /* Do blinky on LED1 while we're waiting for BLE events */
+        ble::AdvertisingParameters adv_parameters(
+            ble::advertising_type_t::CONNECTABLE_UNDIRECTED,
+            ble::adv_interval_t(ble::millisecond_t(1000))
+        );
 
-    if (BLE::Instance().getGapState().connected) {
-        eventQueue.call(updateSensorValue);
-    }
-}
+        _adv_data_builder.setFlags();
+        _adv_data_builder.setAppearance(ble::adv_data_appearance_t::GENERIC_HEART_RATE_SENSOR);
+        _adv_data_builder.setLocalServiceList(mbed::make_Span(&_hr_uuid, 1));
+        _adv_data_builder.setName(DEVICE_NAME);
 
-void onBleInitError(BLE &ble, ble_error_t error)
-{
-    (void)ble;
-    (void)error;
-   /* Initialization error handling should go here */
-}
+        /* Setup advertising */
+
+        ble_error_t error = _ble.gap().setAdvertisingParameters(
+            ble::LEGACY_ADVERTISING_HANDLE,
+            adv_parameters
+        );
 
-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]);
-}
+        if (error) {
+            printf("_ble.gap().setAdvertisingParameters() failed\r\n");
+            return;
+        }
+
+        error = _ble.gap().setAdvertisingPayload(
+            ble::LEGACY_ADVERTISING_HANDLE,
+            _adv_data_builder.getAdvertisingData()
+        );
 
-void bleInitComplete(BLE::InitializationCompleteCallbackContext *params)
-{
-    BLE&        ble   = params->ble;
-    ble_error_t error = params->error;
+        if (error) {
+            printf("_ble.gap().setAdvertisingPayload() failed\r\n");
+            return;
+        }
+
+        /* Start advertising */
 
-    if (error != BLE_ERROR_NONE) {
-        onBleInitError(ble, error);
-        return;
+        error = _ble.gap().startAdvertising(ble::LEGACY_ADVERTISING_HANDLE);
+
+        if (error) {
+            printf("_ble.gap().startAdvertising() failed\r\n");
+            return;
+        }
     }
 
-    if (ble.getInstanceID() != BLE::DEFAULT_INSTANCE) {
-        return;
+    void update_sensor_value() {
+        if (_connected) {
+            // Do blocking calls or whatever is necessary for sensor polling.
+            // In our case, we simply update the HRM measurement.
+            _hr_counter++;
+
+            //  100 <= HRM bps <=175
+            if (_hr_counter == 175) {
+                _hr_counter = 100;
+            }
+
+            _hr_service.updateHeartRate(_hr_counter);
+        }
+    }
+
+    void blink(void) {
+        _led1 = !_led1;
     }
 
-    ble.gap().onDisconnection(disconnectionCallback);
+private:
+    /* Event handler */
 
-    /* Setup primary service. */
-    hrServicePtr = new HeartRateService(ble, hrmCounter, HeartRateService::LOCATION_FINGER);
+    void onDisconnectionComplete(const ble::DisconnectionCompleteEvent&) {
+        _ble.gap().startAdvertising(ble::LEGACY_ADVERTISING_HANDLE);
+        _connected = false;
+    }
+
+    virtual void onConnectionComplete(const ble::ConnectionCompleteEvent &event) {
+        if (event.getStatus() == BLE_ERROR_NONE) {
+            _connected = true;
+        }
+    }
 
-    /* Setup advertising. */
-    ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::BREDR_NOT_SUPPORTED | GapAdvertisingData::LE_GENERAL_DISCOVERABLE);
-    ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LIST_16BIT_SERVICE_IDS, (uint8_t *)uuid16_list, sizeof(uuid16_list));
-    ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::GENERIC_HEART_RATE_SENSOR);
-    ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LOCAL_NAME, (uint8_t *)DEVICE_NAME, sizeof(DEVICE_NAME));
-    ble.gap().setAdvertisingType(GapAdvertisingParams::ADV_CONNECTABLE_UNDIRECTED);
-    ble.gap().setAdvertisingInterval(1000); /* 1000ms */
-    ble.gap().startAdvertising();
+private:
+    BLE &_ble;
+    events::EventQueue &_event_queue;
+    DigitalOut _led1;
+
+    bool _connected;
+
+    UUID _hr_uuid;
 
-    printMacAddress();
-}
+    uint8_t _hr_counter;
+    HeartRateService _hr_service;
 
-void scheduleBleEventsProcessing(BLE::OnEventsToProcessCallbackContext* context) {
-    BLE &ble = BLE::Instance();
-    eventQueue.call(Callback<void()>(&ble, &BLE::processEvents));
+    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()
 {
-    eventQueue.call_every(500, periodicCallback);
+    BLE &ble = BLE::Instance();
+    ble.onEventsToProcess(schedule_ble_events);
 
-    BLE &ble = BLE::Instance();
-    ble.onEventsToProcess(scheduleBleEventsProcessing);
-    ble.init(bleInitComplete);
-
-    eventQueue.dispatch_forever();
+    HeartrateDemo demo(ble, event_queue);
+    demo.start();
 
     return 0;
 }
+
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/source/pretty_printer.h	Mon Jan 14 10:45:44 2019 +0000
@@ -0,0 +1,95 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2018 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 <mbed.h>
+#include "ble/BLE.h"
+
+inline void print_error(ble_error_t error, const char* msg)
+{
+    printf("%s: ", msg);
+    switch(error) {
+        case BLE_ERROR_NONE:
+            printf("BLE_ERROR_NONE: No error");
+            break;
+        case BLE_ERROR_BUFFER_OVERFLOW:
+            printf("BLE_ERROR_BUFFER_OVERFLOW: The requested action would cause a buffer overflow and has been aborted");
+            break;
+        case BLE_ERROR_NOT_IMPLEMENTED:
+            printf("BLE_ERROR_NOT_IMPLEMENTED: Requested a feature that isn't yet implement or isn't supported by the target HW");
+            break;
+        case BLE_ERROR_PARAM_OUT_OF_RANGE:
+            printf("BLE_ERROR_PARAM_OUT_OF_RANGE: One of the supplied parameters is outside the valid range");
+            break;
+        case BLE_ERROR_INVALID_PARAM:
+            printf("BLE_ERROR_INVALID_PARAM: One of the supplied parameters is invalid");
+            break;
+        case BLE_STACK_BUSY:
+            printf("BLE_STACK_BUSY: The stack is busy");
+            break;
+        case BLE_ERROR_INVALID_STATE:
+            printf("BLE_ERROR_INVALID_STATE: Invalid state");
+            break;
+        case BLE_ERROR_NO_MEM:
+            printf("BLE_ERROR_NO_MEM: Out of Memory");
+            break;
+        case BLE_ERROR_OPERATION_NOT_PERMITTED:
+            printf("BLE_ERROR_OPERATION_NOT_PERMITTED");
+            break;
+        case BLE_ERROR_INITIALIZATION_INCOMPLETE:
+            printf("BLE_ERROR_INITIALIZATION_INCOMPLETE");
+            break;
+        case BLE_ERROR_ALREADY_INITIALIZED:
+            printf("BLE_ERROR_ALREADY_INITIALIZED");
+            break;
+        case BLE_ERROR_UNSPECIFIED:
+            printf("BLE_ERROR_UNSPECIFIED: Unknown error");
+            break;
+        case BLE_ERROR_INTERNAL_STACK_FAILURE:
+            printf("BLE_ERROR_INTERNAL_STACK_FAILURE: internal stack faillure");
+            break;
+    }
+    printf("\r\n");
+}
+
+/** print device address to the terminal */
+inline void print_address(const Gap::Address_t &addr)
+{
+    printf("%02x:%02x:%02x:%02x:%02x:%02x\r\n",
+           addr[5], addr[4], addr[3], addr[2], addr[1], addr[0]);
+}
+
+inline void print_mac_address()
+{
+    /* 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: ");
+    print_address(address);
+}
+
+inline const char* phy_to_string(Gap::Phy_t phy) {
+    switch(phy.value()) {
+        case Gap::Phy_t::LE_1M:
+            return "LE 1M";
+        case Gap::Phy_t::LE_2M:
+            return "LE 2M";
+        case Gap::Phy_t::LE_CODED:
+            return "LE coded";
+        default:
+            return "invalid PHY";
+    }
+}