What is a BLE Module?
A BLE module is a small electronic component that contains all the necessary elements to provide Bluetooth Low Energy wireless connectivity. It includes a BLE chipset with radio, microcontroller, crystal, antenna (or U.FL connector), and passive components, all integrated into a compact package. The module also comes pre-programmed with the BLE stack and profiles.
BLE Modules greatly simplify the process of adding BLE to a product. Instead of having to design the BLE functionality from the ground up, engineers can simply add a pre-certified module to their design. This saves significant development time and cost.
Types of BLE Modules
There are two main types of BLE modules:
1. Standalone Modules
Standalone BLE modules contain just the BLE functionality. They communicate with an external host microcontroller (MCU) in the end product via a serial interface like UART, SPI or I2C. The host MCU runs the main application code and uses AT commands or a similar protocol to control the BLE module.
Standalone modules provide the most flexibility since the host MCU can be any type that meets the application requirements. However, they also require more development effort, since the host MCU firmware needs to implement the application layer.
Examples of standalone BLE modules include:
| Module | Chipset | Tx Power | Antenna |
|---|---|---|---|
| HM-10 | TI CC2540 | 0 dBm | Ceramic |
| RN4871 | Microchip RN4871 | 0 dBm | PCB |
| BL652 | Laird BL652 | +4 dBm | U.FL connector |
2. System-on-Chip (SoC) Modules
SoC BLE modules contain both the BLE radio and a microcontroller powerful enough to run user application code. This allows the module to operate standalone, without an external host MCU.
SoC modules provide an all-in-one solution that minimizes external components and reduces development time. However, they are less flexible than standalone modules, since the user application is limited by the resources available on the module’s MCU.
Examples of SoC BLE modules include:
| Module | Chipset | MCU | Flash | RAM | Tx Power | Antenna |
|---|---|---|---|---|---|---|
| BGM113 | Silicon Labs BGM113 | ARM Cortex-M4 | 256 KB | 32 KB | +8 dBm | Ceramic |
| BMD-350 | Nordic nRF52832 | ARM Cortex-M4F | 512 KB | 64 KB | +4 dBm | Ceramic |
| BTM-CYW20719 | Cypress CYW20719 | ARM Cortex-M3 | 512 KB | 256 KB | +4 dBm | Ceramic |
Key Features and Specifications
When selecting a BLE module for a specific application, there are several key features and specifications to consider:
1. Bluetooth Version and Features
All modules support the core BLE functionality, but some offer additional optional features from the latest Bluetooth 5.x specification such as:
- Long Range
- 2 Mbps data rate
- Advertising Extensions
- Angle of Arrival/Departure (AoA/AoD)
Consider which BLE features your application requires.
2. RF Performance
The key RF performance specs for a BLE module are:
- Transmit (TX) power – The maximum power at which the module can transmit. Higher TX power enables longer range.
- Receive (RX) sensitivity – The minimum signal level the module can receive. Better RX sensitivity enables longer range.
Range is ultimately determined by the combined TX power and RX sensitivity of the BLE module and the remote device it is communicating with.
3. Antenna Options
BLE modules are available with different antenna options:
- Ceramic chip antenna – A small chip antenna integrated on the module. It’s the simplest option but provides the shortest range.
- PCB trace antenna – An antenna etched into the module’s PCB. It provides better range than a ceramic antenna but requires more PCB area.
- U.FL connector – Allows connecting an external antenna to the module. It provides the best range but requires an additional antenna component.
The best antenna option depends on the space available in the end product and the range required.
4. Security Features
For applications that require a secure BLE connection, look for modules that offer embedded security features like:
- AES encryption engine
- True Random Number Generator (TRNG)
- Crypto accelerator
- Secure key storage
- Secure Boot
- Secure debugging
These features enable implementing security at both the link layer (encryption and authentication) and application layer.
5. Certifications
BLE modules come with various regulatory certifications such as:
- FCC
- IC
- CE
- RCM
- TELEC
- Bluetooth SIG
Selecting a module with the required certifications for your target markets can save significant time and cost in the certification process for the end product.
6. Software Stack and SDK
SoC modules come with a software development kit (SDK) that includes the BLE stack and profiles, RTOS, peripheral drivers, and code examples.
Consider the following when evaluating a module’s SDK:
- Quality of documentation
- Range of BLE profiles and services supported
- RTOS and programming language choices
- Integration with IDEs and other development tools
- Availability of technical support
A full-featured, well documented SDK can significantly accelerate development.
Applications and Use Cases
BLE modules are used in a wide range of IoT applications across multiple industries, including:
Healthcare and Fitness
- Medical wearables like continuous glucose monitors and ECG sensors
- Fitness trackers
- Smart scales
- Thermometers
Home Automation
- Smart lights
- Smart locks
- Appliance control
- Environmental sensors
Industrial Automation
- Asset tracking
- Machine monitoring
- Environmental sensing
- Access control
Retail and Hospitality
- Beacons for proximity marketing
- Indoor navigation
- Customer analytics
- Mobile point-of-sale
Consumer Electronics
- Smart watches
- VR/AR headsets
- Remote controls
- Gaming peripherals
In each case, BLE modules provide a fast, low-cost way to add wireless connectivity to the product.
FAQ
1. What is the typical range of a BLE module?
The range depends on the TX power, RX sensitivity, and antenna of the module, as well as the environment. In ideal conditions, BLE modules with a ceramic antenna can achieve a range of 10-30 meters. Using a module with an external antenna can extend the range to 100 meters or more.
2. How much power does a BLE module consume?
BLE is designed for low power operation. The exact power consumption depends on the module, but in general, peak current consumption during TX/RX is 5-15 mA, and average current consumption is much lower. BLE modules can last for months or years on a coin cell battery.
3. What is the difference between BLE and Bluetooth Classic?
BLE is designed for low power, low data rate applications, while Bluetooth Classic is designed for high data rate applications like streaming audio. BLE uses a different radio and protocol stack than Bluetooth Classic, and the two are not directly compatible.
4. Can BLE modules be used for mesh networking?
Yes, BLE supports mesh networking through the Bluetooth Mesh standard. Modules that support Bluetooth 5.0 or later can be used in a Bluetooth Mesh network.
5. How do I select the right BLE module for my application?
Consider the following factors when selecting a BLE module:
- Bluetooth version and features required
- Range and RF performance
- Antenna requirements
- Security requirements
- Certifications required for your target markets
- SDK and development tools
Also consider the module vendor’s reputation for quality, reliability, and support. Ordering evaluation kits from multiple vendors and testing them in your application is the best way to make a selection.
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