3.1.4 BLE Fitness Tracker with PIC32CX SG61 Curiosity Ultra Evaluation Board

Description

The application demonstrates a solution based on Microchip products for the health care industry and wearable products. The application displays heart rate readings on a display and posts this Heart Rate data to Microchip Bluetooth Data (MBD) android mobile application via BLE (Bluetooth Low Energy).

The Mikro Elektronika Heart Rate 9 click board is used to read the heart pulse. Mikroelektronika OLED C Click display is used for displaying the heart rate. RNBD451PE Add On Board using the RNBD451 Bluetooth module is used to send the heart rate data over BLE.

The Heart Rate 9 click introduces Microchip's proprietary method of measuring multiple signals in a body using pseudorandom binary sequence generation and phase division multiplexing This algorithm for processing data from the sensor and it can send data for 3 different diodes (green, ir, red) who give out a diagram of the heartbeat and its frequency per minute.

The host MCU PIC32CX SG61 is interfaced with the Heart Rate 9 click over the USART interface, the RNBD451PE Bluetooth module over UART and the OLED C click over SPI Interface.

Modules/Technology Used

Peripheral Modules
- SysTick
- EIC
- SERCOM (SPI)
- SERCOM (USART)
- EVSYS
RNBD Driver
STDIO Library

Hardware Used

Software/Tools Used

This project has been verified to work with the following versions of software tools:

Refer Project Manifest present in harmony-manifest-success.yml under the project folder firmware/src/config/pic32cx_sg61_cult.

Refer the Release Notes to know the MPLAB X IDE and MCC Plugin version.
Install Microchip Bluetooth Data Android App in the Android mobile or
Install Microchip Bluetooth Data iOS App in the iOS mobile

Because Microchip regularly updates tools, occasionally issue(s) could be discovered while using the newer versions of the tools. If the project does not seem to work and version incompatibility is suspected. It is recommended to double-check and use the same versions that the project was tested with. To download original version of MPLAB Harmony v3 packages, refer to document How to Use the MPLAB Harmony v3 Project Manifest Feature (DS90003305).

Setup

Mount the Heart Rate 9 click board on the mikro bus connector of PIC32CX SG61 Curiosity Ultra Evaluation Board.
Mount the OLED C click on one mikroBUS adapter and then connect the adapter to EXT 1 extension header.
Mount the RNBD451PE Add On Board on one mikroBUS adapter and then connect the adapter to EXT 2 extension header.
Power the PIC32CX SG61 Curiosity Ultra Evaluation Board from a Host PC through a Type-A male to Micro-B USB cable connected to Micro-B port (J300) labeled DEBUG USB.

Programming hex file

The prebuilt hex file can be programmed by following the below steps.

Steps to program the hex file

Open MPLAB X IDE.
Close all existing projects in IDE, if any project is opened.
Go to File -> Import -> Hex/ELF File.
In the Import Image File window,
1. Create Prebuilt Project,
  - Click the Browse button to select the prebuilt hex file, located into the hex folder in the downloaded zip file (pic32cx_sg61_fitness_tracker/hex/pic32cx_sg61_cult.X.production.hex).
  - Select Device as PIC32CX1025SG61128.
  - Ensure the proper tool is selected under Hardware Tool and click on Next button.
2. Select Project Name and Folder,
  - Select appropriate project name and folder and click on Finish button
In MPLAB X IDE, click on Make and Program Device button to program the device.
Follow the steps in Running the Demo section below.

Programming/Debugging Application Project

Open the project (pic32cx_sg61_fitness_tracker/firmware/pic32cx_sg61_cult.X) in MPLAB X IDE.
Ensure PIC32CX SG61 Curiosity Ultra is selected as hardware tool to program/debug the application.
Build the code and program the device by clicking on the Make and Program Device button in MPLAB X IDE tool bar.
Follow the steps in Running the Demo section below.

Running the Demo

Before proceeding, install the Microchip Bluetooth Data app on a Smartphone.

Enable Bluetooth and location from Smartphone settings.
Perform reset by unplugging and re-plugging the power cable of PIC32CX SG61 Curiosity Ultra Evaluation Board.
Open the Microchip Bluetooth Data (MBD) app on the smartphone.
Tap on Bluetooth Smart icon on the dashboard. If prompted, allow the application to turn on Bluetooth.
After power-up, the application displays the Microchip logo on the OLED C click board and initializes the bluetooth module if necessary, and the heart rate sensor.
The two LEDs (LED1 and LED2) on the PIC32CX SG61 Curiosity Ultra Evaluation Board will toggle until initialization finishes.
After successful initialization of the heart rate sensor, two integrated LEDs on the Heart Rate 9 click lights up.
On the OLEC C display a message is shown that the application is initializing.
After the application initializes, a message to put the finger on the sensor and press the SW2 switch is shown.
LED0 on the PIC32CX SG61 Curiosity Ultra Evaluation Board will switch OFF.
LED1 on the PIC32CX SG61 Curiosity Ultra Evaluation Board will switch ON.
Scan for Bluetooth devices by tapping START SCAN option on the MBD APP.
The RNBD451PE device should appear as MCHP_PIC32CX_SG16_HR in the list of Bluetooth devices.
Stop the scan and connect the MCHP BLE device by clicking on MCHP_PIC32CX_SG16_HR. This will establish a connection between the MBD BLE application and the RNBD451PE BLE device.
Once BLE device is connected, the application shows the different services screen. Scrolll down and tap on the Heart Rate Service, it will redirect to Sensor Location screen.
In the bottom right corner of the Sensor Location screen, disable and enable the Notify Button.
Place and keep the finger on Pulse Detection Indicator on the heart rate 9 click sensor as shown in the figure below.
Observe the red LED in the middle of the heart lits shortly at short intervals of time. This would be the indication the sensor is correctly reading the pulse.
Press on SW2 to read the sensor.
LED0 on the PIC32CX SG61 Curiosity Ultra Evaluation Board will switch ON.
LED1 on the PIC32CX SG61 Curiosity Ultra Evaluation Board will switch OFF.
Wait till the LED0 on PIC32CX SG61 Curiosity Ultra Evaluation Board goes OFF and LED1 goes ON.
The user can more reads by clicking SW2 without removing the finger from the sensor.
Note: Make sure smartphone screens are not turned off and do not switch to any other App(s) on the smartphone.
The heart rate value (in bpm - beats per minute) should be displayed on the Sensor Location screen as shown in the image below.
Also, the same heart rate value should be displayed on the OLED C display.