bluetooth_explorer_kit_bio_sensor_oled

Bluetooth - HRM/SpO2 Measurement

Overview

This example implements the Heart Rate service and Pulse Oximeter service. It enables a peer device to connect and receive Heart Rate and Pulse Oximeter values via Bluetooth. The HRM/SpO2 values are measured by using a bio-sensor located on the Heart Rate 2 Click board and displayed on the OLED screen located on the SparkFun Micro OLED Breakout (Qwiic) board.

This code example has related code examples, which may be worth reading before. Find them here:

• OLED SSD1306 driver.

• MAX86161 driver.

• HRM/SpO2 Software Demo without OLED display.

Gecko SDK version

• GSDK v4.4.0
• Third Party Hardware Drivers v2.0.0.0

Hardware Required

• BGM220 Bluetooth Module Explorer Kit - BGM220-EK4314A board.

• Mikroe Heart Rate 2 Click board.

• SparkFun Micro OLED Breakout (Qwiic) board.

NOTE: Tested boards for working with this example:

Board ID	Description
BRD2703A	EFR32xG24 Explorer Kit - XG24-EK2703A
BRD4314A	BGM220 Bluetooth Module Explorer Kit - BGM220-EK4314A
BRD4108A	BG22 Bluetooth SoC Explorer Kit - BG22-EK4108A

Connections Required

The Heart Rate 2 Click board can just be "clicked" into its place. Be sure that the board's 45-degree corner matches the Explorer Kit's 45-degree white line.

The SparkFun Micro OLED Breakout (Qwiic) board can be easily connected by using a Qwiic cable.

Setup

To test this application, you can either create a project based on an example project or start with a "Bluetooth - SoC Empty" project based on your hardware.

Create a project based on an example project

1. From the Launcher Home, add your hardware to My Products, click on it, and click on the EXAMPLE PROJECTS & DEMOS tab. Find the example project with the filter "hrm".

2. Click Create button on the Bluetooth - HRM/Sp02 Measurement example. Example project creation dialog pops up -> click Create and Finish and Project should be generated.

3. Build and flash this example to the board.

Start with a "Bluetooth - SoC Empty" project

1. Create a Bluetooth - SoC Empty project for your hardware using Simplicity Studio 5.

2. Copy all attached files in inc and src folders into the project root folder (overwriting existing).

3. Import the GATT configuration:

   • Open the .slcp file in the project.

   • Select the CONFIGURATION TOOLS tab and open the Bluetooth GATT Configurator.

   • Find the Import button and import the configuration bluetooth_explorer_kit_bio_sensor_oled/config/btconfig/gatt_configuration.btconf file.

   • Save the GATT configuration (ctrl-s).

4. Open the .slcp file. Select the SOFTWARE COMPONENTS tab and install the software components:

   • [Services] → [IO Stream] → [IO Stream: USART] → default instance name: vcom.

   • [Application] → [Utility] → [Log]

   • [Platform] → [Driver] → [I2C]→ [I2CSPM] → create new instances: mikroe and qwiic.

   • [Platform] → [Driver] → [Button] [Simple Button] → create an instance: btn0.

   • [Third Party Hardware Drivers] → [Display & LED] → [SSD1306 - Micro OLED Breakout (SparkFun) - I2C].

   • [Third Party Hardware Drivers] → [Services] → [GLIB - OLED Graphic Library].

5. Build and flash the project to your device.

Note:

• Make sure that the Third Party Hardware Drivers Extension already be installed and this repository is added to Preferences > Simplicity Studio > External Repos.

• Do not forget to flash a bootloader to your board, see Bootloader for more information.

How It Works

GATT Database

GATT Database

• Device name: Silabs HR Example

• [Service] Generic Access

• [Service] Device Information

• [Service] Heart Rate

  • [Char] Heart Rate Measurement
  • [Char] Body Sensor Location
  • [Char] Heart Rate Control Point

• [Service] Pulse Oximeter Service

  • [Char] PLX Spot-Check Measurement
  • [Char] PLX Continuous Measurement
  • [Char] PLX Features
  • [Char] Record Access Control Point

Testing

Upon reset, the application will display the Silicon Labs' logo on the OLED screen for three seconds. Then the OLED display will be off to save energy. Follow the below steps to test the example:

You can use a smartphone app, such as the EFR Connect application on your phone, to connect to the board. Please, follow some steps below:

• Open the EFR Connect app.

• Open the Bluetooth Browser.

• Find the device advertising as Silabs HR Example.

• Click on Connect button.

  

You can use the BTN0 button to start or stop the measurement at any time. When starting the HRM/SpO2 measurement, you should put your finger on the sensor with appropriate pressure (solid contact between the finger and the sensor without optical leakage and don’t press with a too large force) and stay idle for at least 10 seconds. Then check the measured Heart Rate and Pulse Oximeter values on the OLED screen and the EFR Connect application on your smartphone.

Heart Rate Service:

You have to enable Notify for the Heart Rate Measurement characteristic. You can see the change of value, it represents your heart rate. After that, the notification will be sent every 500 milliseconds from the device. The normal heart rate of a healthy person is frequently in the range of 60-100 beats/minute at rest. The average person's SpO2 should be between 95 and 100%.

OLED display:

On the OLED screen, you can see the measured heart rate and Sp02 value. That value is allocated according to the icon and description on the left. Values also will be updated every 500 milliseconds.

You can launch the Console that is integrated into Simplicity Studio or can use a third-party terminal tool like TeraTerm to receive the logs from the virtual COM port. The raw data in each column represents "green LED, IR LED, red LED”. Heart rate and SpO2 values are updated once a second. The user can easily log the raw samples and debug messages to a *.csv file for post-analysis.