Bluetooth: Continuous Glucose Monitoring Service

The Continuous Glucose Monitoring Service sample demonstrates how to implement the Continuous Glucose Monitoring Service profile using nRF Connect SDK Bare Metal option.

Requirements

The sample supports the following development kits:

The following board variants do not have DFU capabilities:

S115:

Hardware platform

PCA

Board target

nRF54L15 DK

PCA10156

bm_nrf54l15dk/nrf54l15/cpuapp/s115_softdevice

nRF54L15 DK (emulating nRF54L10)

PCA10156

bm_nrf54l15dk/nrf54l10/cpuapp/s115_softdevice

nRF54L15 DK (emulating nRF54L05)

PCA10156

bm_nrf54l15dk/nrf54l05/cpuapp/s115_softdevice

nRF54LM20 DK

PCA10184

bm_nrf54lm20dk/nrf54lm20a/cpuapp/s115_softdevice

nRF54LS05 DK

PCA10214

bm_nrf54ls05dk/nrf54ls05b/cpuapp/s115_softdevice

nRF54LV10 DK

PCA10188

bm_nrf54lv10dk/nrf54lv10a/cpuapp/s115_softdevice

S145:

Hardware platform

PCA

Board target

nRF54L15 DK

PCA10156

bm_nrf54l15dk/nrf54l15/cpuapp/s145_softdevice

nRF54L15 DK (emulating nRF54L10)

PCA10156

bm_nrf54l15dk/nrf54l10/cpuapp/s145_softdevice

nRF54L15 DK (emulating nRF54L05)

PCA10156

bm_nrf54l15dk/nrf54l05/cpuapp/s145_softdevice

nRF54LM20 DK

PCA10184

bm_nrf54lm20dk/nrf54lm20a/cpuapp/s145_softdevice

nRF54LS05 DK

PCA10214

bm_nrf54ls05dk/nrf54ls05b/cpuapp/s145_softdevice

nRF54LV10 DK

PCA10188

bm_nrf54lv10dk/nrf54lv10a/cpuapp/s145_softdevice

Overview

The Continuous Glucose Monitoring Service (CGMS) is a service that exposes glucose and other data from a personal Continuous Glucose Monitoring sensor.

Allow list

By default, the sample does not use allow-list advertising, which means that any nearby device can connect and bond with the device. Bonded devices are stored in internal non-volatile memory (NVM) and are remembered across power cycles.

You can enable allow-list advertising by setting the CONFIG_BLE_ADV_USE_ALLOW_LIST Kconfig option to y in the base Kconfig fragment (prj.conf). When enabled, only previously bonded devices are allowed to reconnect, which allows faster reconnection and prevents unknown devices from connecting.

When allow-list advertising is enabled and you want to add a new bonded device, existing bonds must first be deleted. This can be done through user interaction, as described in the user interface section.

User interface

Button 0:

When pairing with authentication, press this button to confirm the passkey shown in the COM listener and complete pairing with the other device. See Testing.

Button 1:

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

When pairing with authentication, press this button to reject the passkey shown in the COM listener to prevent pairing with the other device.

Button 2:

Decrease the simulated glucose concentration.

Button 3:

Increase the simulated glucose concentration.

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 samples/bluetooth/ble_cgms/ in the Bare Metal folder structure.

For details on how to create, configure, and program a sample, see Getting Started with the samples.

Testing

  1. Compile and program the application.

  2. Connect the device to the computer.

  3. Connect to the kit with a terminal emulator (for example, the Serial Terminal app). Note that the kit has two UARTs, where only one will output the log.

  4. Reset the kit.

  5. In the Serial Terminal, observe that the BLE CGMS sample initialized message is printed.

  6. Observe that the Advertising as nRF_BM_CGMS message is printed. You can configure this name using the CONFIG_SAMPLE_BLE_DEVICE_NAME Kconfig option. For information on how to do this, see Configuring Kconfig.

  7. Connect to your device using the nRF Toolbox mobile application with the Continuous Glucose service. If the device is not advertising, reset the board with the Reset Board option in Visual Studio Code or by pressing the reset button on the development kit.

  8. Your mobile phone should now attempt to pair with your device to encrypt the link. When prompted, check that the passkeys are the same before confirming by pressing Button 0 on the kit and confirming on the mobile phone.

  9. Observe that the text Connected and CGMS Start Session is printed in the COM listener.

  10. Observe that you receive the CGMS records in the mobile application. The default time between each record is one minute.