.. _ble_hrs_central_sample:

Bluetooth: Heart Rate Service Central
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.. contents::
   :local:
   :depth: 2

The Heart Rate Service Central sample demonstrates how you can implement the Heart Rate and Battery Level profiles as a client using |BMlong|.

Requirements
************

The sample supports the following development kits:

.. tabs::

   .. group-tab:: Simple board variants

      The following board variants do **not** have DFU capabilities:

      .. include:: /includes/supported_boards_all_non-mcuboot_variants_s145.txt

   .. group-tab:: MCUboot board variants

      The following board variants have DFU capabilities:

      .. include:: /includes/supported_boards_all_mcuboot_variants_s145.txt

Overview
********

This sample scans for devices that advertise with the :ref:`lib_ble_service_hrs` UUID (0x180D) and initiates a connection when a device is found.
When a device is connected, the sample starts the service discovery procedure.
If this succeeds, the sample subscribes to the Heart Rate Measurement characteristic to receive heart rate notifications and the Battery Level characteristic to receive battery level notifications.

.. _ble_hrs_central_sample_testing:

User interface
**************

Button 0:
  Press to disable allow list.

Button 1:
  Press to disconnect from the connected peer device.

  Keep the button pressed while resetting the board to delete bonding information for all peers stored on the device.

LED 0:
   Lit when the device is initialized.

LED 1:
   Lit when a device is connected.

Building and running
********************

This sample can be found under :file:`samples/bluetooth/ble_hrs_central/` in the |BMshort| folder structure.

For details on how to create, configure, and program a sample, see :ref:`getting_started_with_the_samples`.

Testing
=======

This sample requires two devices to test, one running this sample and another one running the :ref:`ble_hrs_sample` sample.

Complete the following steps to test the sample:

1. Compile and program the application.
#. In the Serial Terminal, observe that the ``BLE HRS Central sample initialized`` message is printed.
#. Program the other development kit with the :ref:`ble_hrs_sample` sample and reset it.
#. Observe that the ``Scan filter match`` message is printed, followed by ``Connecting to target`` and ``Connected``.
#. Observe that the ``Heart rate service discovered.`` message is printed.
#. Observe that the device starts receiving heart rate and battery level measurement notifications.