ANT: ANT+ Heart Rate Monitor Receiver

The Heart Rate Monitor Receiver sample shows the usage of the ANT+ Heart Rate Monitor profile.

Overview

This sample simulates a Heart Rate Monitor Receiver. The Receiver application connects to the nearest heart rate monitor (HRM) in range and prints out incoming page data. The actual channel state is indicated by the ANT channel state indicator.

On dual core, this sample uses sysbuild to add a network core image to the build by defining the ‘’NRF_DEFAULT_ANT_ONLY’’ with a default value of ‘’y’’ in Kconfig.sysbuild.

Channel configuration

This example uses the default channel configuration:

Parameter

Transmitter

Receiver

Channel type

Master (0x10)

Slave (0x00)

Network key

ANT+

ANT+

RF channel

57 (2457 MHz)

57 (2457 MHz)

Device number

0x31 (49)

0x31 (49)

Device type

0x78 (120)

0x78 (120)

Transmission type

0x01

0x01

Channel period

8070 (4.06 Hz)

8070 (4.06 Hz)

Requirements

Hardware platforms

PCA

Board name

Build target

nRF5340 DK

PCA10095

nrf5340dk/nrf5340

nrf5340dk/nrf5340/cpuapp

nRF52840 DK

PCA10056

nrf52840dk/nrf52840

nrf52840dk/nrf52840

Building and running

This sample can be found under ant/samples/ant_plus/ant_hrm/hrm_rx in the nRF Connect SDK folder structure.

ANT+ Network Key

This sample selects CONFIG_ANT_KEY_MANAGER to provide access to ant_plus_key_set() (See ANT Key Manager Library). This library function configures the pre-defined ANT+ Network Key for ANT+ devices. Note that network keys, transmission type, device type IDs and RF channels are assigned and regulated to maintain network integrity, and interoperability, except for the default public network.

For more information on Network Keys, visit https://www.thisisant.com/developer/ant-plus/ant-plus-basics/network-keys.

Testing

You can test the Heart Rate Monitor Receiver by performing the following steps:

  1. Compile and program the Heart Rate Monitor Receiver.

  2. Compile and program the HRM Transmitter to another supported board to act as an ANT peer device. Alternatively, use SimulANT+ as described below.

  3. On the nRF DK side, connect to the virtual COM port to view the ANT+ HRM pages received.

    [00:00:00.273,498] <inf> hrm_rx: ANT+ HRM RX sample starting...
    [00:00:00.275,329] <inf> ant_hrm: ANT HRM channel 0 init
    [00:00:00.276,611] <inf> ant_hrm: ANT HRM channel 0 open
    [00:00:00.366,912] <inf> ant_hrm: HRM RX Page Number: 0
    [00:00:00.366,912] <inf> ant_hrm_page_0: Heart beat count:                 97
    [00:00:00.366,912] <inf> ant_hrm_page_0: Computed heart rate:              72
    [00:00:00.366,943] <inf> ant_hrm_page_0: Heart beat event time:            16.804s
    
    [00:00:00.366,943] <inf> hrm_rx: Page was updated
    [00:00:00.613,159] <inf> ant_hrm: HRM RX Page Number: 0
    [00:00:00.613,159] <inf> ant_hrm_page_0: Heart beat count:                 97
    [00:00:00.613,189] <inf> ant_hrm_page_0: Computed heart rate:              72
    [00:00:00.613,220] <inf> ant_hrm_page_0: Heart beat event time:            16.804s
    

Testing the HRM examples with the ANT+ Simulator tools

You can use the SimulANT+ Heart Rate Sensor Simulator to test the HRM Receiver. Make sure the Device Number matches the Channel Configuration above (0x31). See the documentation of the ANT+ Simulator tools at thisisant.com for information about how to use these tools.