nRF Connect SDK Hands-On: Rapid Prototyping with Bluetooth LE and LED Button Service

Summary:

This video, part of a series, introduces the nRF Connect SDK and guides users through rapidly prototyping a Bluetooth LE application.

The nRF Connect SDK is a comprehensive, modular, and scalable SDK for IoT applications.
A typical Bluetooth LE application involves a wireless System-on-Chip (SoC) connecting to sensors, storing data, establishing wireless connections (e.g., with a smartphone), optimizing for low power, and supporting over-the-air updates.
The SDK offers robust Bluetooth LE support, including a qualified stack, rich libraries, numerous samples, full applications, and essential development tools like the Power Profiler and nRF Connect for Mobile.
The tutorial demonstrates setting up the development environment using nRF Command Line Tools, nRF Connect for Desktop, and the Quick Start application.
It walks through flashing the pre-compiled Peripheral LED Button Service (LBS) sample onto an nRF52840 Development Kit and verifying its functionality using the nRF Connect for Mobile app to control LEDs and monitor buttons.
Finally, the video covers setting up the Visual Studio Code environment, installing the nRF Connect for VS Code extension, installing the toolchain and SDK, copying the LBS sample as a new application, and building and flashing it from source.

Overview of a typical Bluetooth LE application [ 00:00:50 ]

Introduction to nRF Connect SDK and Bluetooth LE Applications [00:00:00]

The nRF Connect SDK is a comprehensive, modular, and scalable software development kit designed for building Internet of Things (IoT) applications. It provides essential building blocks and offers high levels of modularity, scalability, and portability.

The video series will focus on building a typical Bluetooth Low Energy (LE) application.
- A typical Bluetooth LE application architecture [00:00:50]
  - Wireless System-on-Chip (SoC): The core component, connecting to onboard elements like LEDs, buttons, and various sensors (environmental or motion-based).
  - Data Handling: The SoC gathers, processes, and stores data in non-volatile memory.
  - Wireless Connectivity: Establishes a connection with an external Bluetooth LE device, such as a smartphone, to access real-time and historical data, and control the system.
  - Power Efficiency: Applications are typically designed for low power consumption, enabling extended battery operation.
  - Over-the-Air Updates (FOTA): Includes mechanisms for over-the-air updates to deliver bug fixes and security patches.
- The initial focus will be on integrating Bluetooth LE connection functionality to wirelessly control LEDs and monitor button status.
  
  A conceptual diagram of a typical Bluetooth Low Energy (LE) application, showing a wireless SoC connected to various sensors, memory, and a battery, communicating wirelessly with a smartphone. [ 00:00:50 ]

nRF Connect SDK Bluetooth LE Support [00:02:19]

The nRF Connect SDK provides excellent support for Bluetooth LE features.

A diagram illustrating the Bluetooth LE stack support within the nRF Connect SDK, showing how the user's application interacts with samples, libraries, middleware, the Zephyr RTOS, and the underlying hardware. [ 00:02:20 ]

Qualified Bluetooth LE Stack: Known for stability, reliability, and excellent mobile phone interoperability.
Rich Set of Bluetooth LE Libraries and Services:
- Includes standard GATT profiles and services (e.g., Battery Service, Continuous Glucose Monitoring Service).
- Features Nordic's custom profiles and services (e.g., LED Button Service, Nordic UART Service, Nordic Status Message Service).
Large Selection of Samples: Over 100 samples available, often used as starting points, with some including custom mobile applications for testing.
Full-Fledged Bluetooth LE Applications:
- nRF Desktop: For HID keyboard and mouse.
- nRF5340 Audio: For audio over Bluetooth LE using synchronous channels and the LC3 codec.
Powerful Tools: Includes the Power Profiler and nRF Connect for Mobile app, essential for development, debugging, and testing.
Educational Resources: Extensive training and educational materials available through the Nordic Developer Academy.

Quick Start: Setting Up the Development Environment and Flashing a Sample [00:04:20]

The Quick Start application simplifies the onboarding process for new users.

Required Tools Installation:
1. Install nRF Command Line Tools (includes J-Link software).
2. Install nRF Connect for Desktop.
3. Launch the Quick Start application within nRF Connect for Desktop.
Development Kit (DK): The demonstration uses an nRF52840 Development Kit, but the demo can be followed with any Bluetooth LE capable Nordic DK (nRF52, nRF53, nRF54 series).

An nRF52840 Development Kit connected via USB, alongside a smartphone, ready for Bluetooth LE application development. [ 00:05:08 ]
Flashing a Pre-compiled Sample [00:07:20]:
- The Quick Start app detects the connected DK and offers a list of pre-compiled samples.
- Select the Peripheral LED Button Service (LBS) sample.
  - This sample handles Bluetooth LE stack initialization and configures the device as a Bluetooth LE peripheral.
  - It advertises its presence and awaits a connection from a central device (e.g., a mobile phone).
  - The LBS sample demonstrates controlling LEDs and monitoring buttons on the board.
- Flash the selected sample to the DK.
Verifying the LBS Sample Functionality [00:09:05]:
- The DK will start advertising (LED 1 blinking).
- Use the nRF Connect for Mobile app (Android/iOS) or the nRF Blinky app to connect to the peripheral device.
- Upon connection, LED 2 on the DK should turn on.
- Enable notifications for the button characteristic in the mobile app.
- Pressing Button 1 on the DK will update the button status in the mobile app.
- Control LED 3 by writing "ON" or "OFF" values to its characteristic via the mobile app.
  
  The nRF Connect for Mobile app interface displaying a list of nearby Bluetooth LE devices during a scan, with "Peripheral LBS" identified as a connectable device. [ 00:10:46 ]
  
  The nRF Connect for Mobile app interface showing the "Nordic LED Button Service" details, including button status and LED control options. [ 00:11:16 ]

Setting Up Visual Studio Code for Application Development [00:12:26]

To work with the source code and develop custom applications.

Open VS Code: The nRF Connect SDK is IDE agnostic, but VS Code is the recommended environment due to excellent extension support.
Install nRF Connect for Visual Studio Code Extension: This extension streamlines the development process.

The Visual Studio Code interface displaying the nRF Connect extension's "Getting started" view, prompting to install the toolchain. [ 00:13:45 ]
Install Toolchain [00:13:46]:
- From the nRF Connect extension, select "Install Toolchain".
- Choose the latest tagged version (e.g., 2.7.0).
Install nRF Connect SDK [00:14:43]:
- From the nRF Connect extension, select "Manage SDK" and then "Install SDK".
- Select the SDK version that matches the installed toolchain (e.g., 2.7.0).
Create a New Application [00:15:43]:
- From the Welcome view, click "Create a new application".
- Choose "Copy a sample" and select the "LED Button Service" example as the base.
- Specify a path for the new application.
Add Build Configuration [00:16:53]:
- In the nRF Connect extension, add a build configuration.
- Select the target hardware, e.g., "nRF52840 Development Kit" and the "nRF52840 SoC".
  
  A screenshot of the "Add Build Configuration" window in Visual Studio Code, showing options to select the target board and SoC for the application build. [ 00:17:04 ]
Build and Flash the Application [00:17:30]:
- Build the application to generate binaries.
- Flash the compiled application to the development kit.
Verify Functionality: Open the serial terminal in VS Code and reset the board to see the output, confirming the application is running from the newly built source code.