BLE Signal Strength Monitoring in real-time Using Renesas RA4M2

2024-08-19 | By Sheikh Shuhad

License: General Public License Bluetooth / BLE

Introduction

This project demonstrates how to leverage the Renesas RA4M2 microcontroller, combined with the BleuIO Bluetooth Low Energy (BLE) USB dongle, to perform a wireless signal strength scan. It provides a practical example of how to use the USB Host Communication Device Class (HCDC) driver to communicate with a BLE device, highlighting how easy it is to create BLE applications using the BleuIO dongle.

By integrating these technologies, the project enables users to scan for nearby BLE devices, parse the Received Signal Strength Indicator (RSSI) from advertising data, and display it in real time using the RTTViewer. This setup offers a hands-on approach to understanding BLE communication and signal strength analysis.

Requirements

EK-RA4M2
BleuIO – Bluetooth Low Energy USB Dongle
FSP Platform Installer (Includes e² studio IDE, toolchain, and FSP packs)
J-Link RTT Viewer
USB OTG Cable (USB-A, USB-B micro)
A Closebeacon (Recommended) or other BLE device that advertises.
Our example project [Download from GitHub]

Setup

Connect a Micro USB device cable (type-A male to micro-B male) between J10 (Debug1) and a Computer USB port.
Plug in a BleuIO Dongle in the USB OTG Cable (type-A female to micro-B male) and connect it to J11 (USB Full Speed).
Make sure Jumper J12 is placed on pins 1-2
Remove Jumper J15 pins

Importing project

Open e² studio IDE
Choose a workspace and click ‘Launch’
Download or clone the example project. Place the folder ‘bleuio_ra4m2_rssi_scan_example’ in workspace.
Choose Import Project
Select ‘Existing Projects into Workspace’ under the ‘General’ tab:

ble signal strength monitor

Click the ‘Browse…’ button and open the folder where the ‘bleuio_ra4m2_rssi_scan_example’ project folder is located:

ble signal strength monitor

Finally select the project and click ‘Finish’. You have now imported the project!

Running the example

Go to file ‘usb_hcdc_app.c’ under ‘src/’ and edit line 54 to the mac address of the desired:

#define ADDR_TO_SCAN "[0]D0:76:50:80:01:75"

[0] = public address
[1] = private addressOn a closebeacon the mac address is printed on the back of the box (it will need to be converted to Hex):

ble signal strength monitor

For example: 208-118-080-128-001-117 in Hex is: D0-76-50-80-01-75

Build the project by clicking the building icon:

ble signal strength monitor

Use Debug to download and run the project. The first time you need to configure the debug settings. Click down arrow to the right of the Debug icon and select ‘Debug Configurations…

ble signal strength monitor

’Under ‘Renesas GDB Hardware Debugging’ select ‘bleuio_ra4m2_rssi_scan_example.elf’ and click ‘Debug’.

ble signal strength monitor

The debug is now configured, and the ‘Debug’ icon can be used next time to run the project.
Open RTTViewer. Connect and use these settings:
Connection to J-Link: USBSpecify Target Device: R7FA4M2ADTarget Interface & Speed: SWD 4000kHzRTT Control Block: Address 0x2000095c

ble signal strength monitor

On the debugger screen in e² studio click the ‘Resume’ icon twice to run the project.

ble signal strength monitor

You should now see the output on the RTTViewer. Notice that when you move the scanned device closer to the BleuIO the RSSI value will increase.

Output

Below is the output screen that displays the RSSI values in real-time as the BleuIO dongle scans for nearby BLE devices:

ble signal strength monitor

Practical Use Cases

The BleuIO RA4M2 RSSI Scan Project can be applied in various scenarios where monitoring BLE signal strength is critical:

Proximity-Based Applications: By tracking RSSI values, developers can create proximity-based applications where actions are triggered based on the distance between BLE devices, such as automated check-ins, asset tracking, or location-based services.
Signal Strength Mapping: The project can be used to map signal strength in different environments, helping to optimize the placement of BLE devices like beacons in smart homes, retail stores, or industrial settings.
Device Tracking and Monitoring: In IoT applications, RSSI can be used to monitor the presence and movement of devices within a specific range, useful in security systems, inventory management, or environmental monitoring.

This project not only showcases the capabilities of the BleuIO dongle but also serves as a foundation for developing more complex BLE applications. Whether you’re a hobbyist, developer, or engineer, this project provides valuable insights into BLE communication and its practical applications.