BLE Heart Rate Service. More...

#include <HeartRateService.h>

Data Structures
struct	HeartRateValueBytes

Public Types

Public Member Functions
	HeartRateService (BLE &_ble, uint16_t hrmCounter, BodySensorLocation location)
	Construct and initialize a heart rate service. More...

void	updateHeartRate (uint16_t hrmCounter)
	Update the heart rate that the service exposes. More...

Protected Member Functions
void	setupService ()
	Construct and add to the GattServer the heart rate service. More...

Detailed Description

BLE Heart Rate Service.

purpose

Fitness applications use the heart rate service to expose the heart beat per minute measured by a heart rate sensor.

Clients can read the intended location of the sensor and the last heart rate value measured. Additionally, clients can subscribe to server initiated updates of the heart rate value measured by the sensor. The service delivers these updates to the subscribed client in a notification packet.

The subscription mechanism is useful to save power; it avoids unecessary data traffic between the client and the server, which may be induced by polling the value of the heart rate measurement characteristic.

usage

When this class is instantiated, it adds a heart rate service in the GattServer. The service contains the location of the sensor and the initial value measured by the sensor.

Application code can invoke updateHeartRate() when a new heart rate measurement is acquired; this function updates the value of the heart rate measurement characteristic and notifies the new value to subscribed clients.

Note: You can find specification of the heart rate service here: https://www.bluetooth.com/specifications/gatt

Attention: The service does not expose information related to the sensor contact, the accumulated energy expanded or the interbeat intervals.; The heart rate profile limits the number of instantiations of the heart rate services to one.

Definition at line 67 of file HeartRateService.h.

Member Enumeration Documentation

enum BodySensorLocation

Intended location of the heart rate sensor.

Enumerator
LOCATION_OTHER	Other location.
LOCATION_CHEST	Chest.
LOCATION_WRIST	Wrist.
LOCATION_FINGER	Finger.
LOCATION_HAND	Hand.
LOCATION_EAR_LOBE	Earlobe.
LOCATION_FOOT	Foot.

Definition at line 72 of file HeartRateService.h.

Constructor & Destructor Documentation

HeartRateService	(	BLE &	_ble,
		uint16_t	hrmCounter,
		BodySensorLocation	location
	)

Construct and initialize a heart rate service.

The construction process adds a GATT heart rate service in _ble GattServer, sets the value of the heart rate measurement characteristic to hrmCounter and the value of the body sensor location characteristic to location.

Parameters

[in]	_ble	BLE device that hosts the heart rate service.
[in]	hrmCounter	Heart beats per minute measured by the heart rate sensor.
[in]	location	Intended location of the heart rate sensor.

Definition at line 123 of file HeartRateService.h.

Member Function Documentation

void setupService ( )

protected

Construct and add to the GattServer the heart rate service.

Definition at line 167 of file HeartRateService.h.

void updateHeartRate ( uint16_t hrmCounter )

Update the heart rate that the service exposes.

The server sends a notification of the new value to clients that have subscribed to updates of the heart rate measurement characteristic; clients reading the heart rate measurement characteristic after the update obtain the updated value.

Parameters

[in] hrmCounter Heart rate measured in BPM.

Attention: This function must be called in the execution context of the BLE stack.

Definition at line 154 of file HeartRateService.h.

Data Structures

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Important Information for this Arm website