In today’s world where the Internet of Things (IoT) and smart devices are ubiquitous, a key challenge in product design is enabling billions of sensors, wearables, and smart home products to operate stably for weeks, months, or even years on limited battery capacity. Bluetooth Low Energy (BLE or Bluetooth LE) technology was born precisely to address this core contradiction. It is not a simple "slowed-down version" of traditional Bluetooth, but a wireless communication protocol entirely redesigned for scenarios requiring extremely low power consumption and intermittent data transmission. This article will take EBYTE’s rich BLE module product line as an example to deeply analyze the core principles, key features, and wide-ranging applications of BLE technology in the IoT.

Core Design Philosophy of BLE

Unlike traditional Bluetooth (Bluetooth Classic), which focuses on continuous high-bandwidth data streams (such as audio transmission), BLE was originally designed to enable occasional, fast exchange of small batches of data between devices with extremely low average power consumption. This design philosophy is reflected in every aspect of its operation:

  • Duty Cycling: This is the cornerstone of BLE’s low power consumption. Devices spend most of their time in deep sleep, only "waking up" for extremely short preset time windows to broadcast or listen. The "advertising interval", "connection interval", and "scanning interval" repeatedly mentioned in the documents are manifestations of this mechanism. The longer the interval, the lower the power consumption, but the slower the device is discovered or responds; the opposite is also true. Developers can flexibly configure these parameters according to application requirements (e.g., smart door locks need fast response, while temperature and humidity sensors can report data every few minutes).

  • Streamlined Protocol Stack: The BLE protocol stack has a simpler structure, faster connection establishment (taking only a few milliseconds), and low packet overhead. This allows devices to quickly complete data transmission and return to sleep mode.

  • Optimized Data Channels: Once a connection is established, master and slave devices exchange data in very regular and short connection events, with the RF part completely turned off the rest of the time, greatly reducing the average current.

Key Features and Evolution of BLE Technology 

EBYTE’s product line covers the complete protocol versions from BLE 4.2 to BLE 5.3, with each version upgrade bringing key capability improvements:

  • BLE 4.2: Lays the foundation for modern BLE applications, introducing low-power secure connections and faster data transmission rates. Representative modules include the E73-2G4M04S1D based on nRF51822.

  • BLE 5.0: A major leap forward. Core features include:

    • 2M PHY: Increases the physical layer rate from 1Mbps to 2Mbps. When the signal is good, data transmission is faster and power consumption is lower (because the RF is on for a shorter time). Modules such as E104-BT51A and E104-BT5032A in the documents support this feature.

    • LE Coded PHY (Long-Range Mode): Greatly improves reception sensitivity through forward error correction coding, increasing the theoretical communication distance to 4 times the original. For example, the E104-BT53C3 module supports 125K/500K coding rates and is designed for long-range applications.

    • Advertising Extension: Significantly increases the advertising data capacity from 31 bytes to 255 bytes, allowing more information (such as sensor data and device status) to be carried, and even enabling "connectionless" data transmission (advertising + scan response).

  • BLE 5.1/5.2/5.3: Continuous optimization based on 5.0:

    • 5.1 Direction Finding: Uses Angle of Arrival (AoA) and Angle of Departure (AoD) technologies to achieve centimeter-level indoor positioning, suitable for asset tracking and indoor navigation. The E101-C5WN8 (WiFi6 + Bluetooth module) document mentions this function.

    • 5.2 Enhanced Attribute Protocol (EATT) and LE Power Control: EATT improves multitasking concurrency efficiency; LE Power Control allows devices to dynamically adjust transmit power to further save energy while ensuring connection stability.

    • 5.3 Enhanced Periodic Advertising and Encryption Key Size Control: Further improves advertising efficiency and flexibility in security management.

Understanding BLE Application Forms Through Module Selection

EBYTE’s BLE module product matrix clearly shows how BLE technology adapts to different scenarios:

  • Simple Slave Transparent Transmission (Cost Priority):

    • Typical Modules: E104-BT51A, E104-BT09.

    • Features: Only supports slave mode, with functions focused on "UART-to-BLE". The device automatically broadcasts after power-on, waits for connection from a mobile phone or gateway (master), and then performs bidirectional data transparent transmission. This is the most classic architecture for smart sensors, remote controls, and data acquisition terminals, with a simple structure and extremely low cost.

  • Master-Slave Integrated (Flexible Networking):

    • Typical Modules: E104-BT5032A, E104-BT5011A, E104-BT5005A.

    • Features: The module can be configured as a master, slave, or observer. As a master, it can actively scan and connect to other BLE slave devices (such as sensors); as a slave, it can be connected by a mobile phone. This allows a single module to build a small star network (one master, multiple slaves), such as a smart gateway connecting multiple sensors simultaneously.

  • Bluetooth Mesh Network (Large-Scale Self-Organizing Network):

    • Typical Module: E104-BT11.

    • Features: Builds a many-to-many Mesh network based on the BLE advertising channel. Nodes in the network can relay messages, enabling ultra-large-scale device networking (theoretically up to tens of thousands of nodes) with network self-healing capabilities. The documents detail roles such as Low Power Nodes (LPN), Friend Nodes, and Relay Nodes, making it an ideal choice for scenarios like smart lighting and building automation.

  • High Performance and Integration (Functional Composite):

    • Typical Modules: E104-BT53C3, E101-C5WN8.

    • Features: Supports the latest BLE 5.2/5.3 features with stronger performance. The E104-BT53C3 supports multi-role concurrency, high-speed transparent transmission (50KB/s measured), and large MTU (247 bytes). The E101-C5WN8 integrates WiFi 6, BLE 5.2, and Zigbee/Thread (802.15.4) into one, becoming the core of smart home central controls or complex edge devices.

  • Professional Applications (Audio, Industrial Interfaces):

    • Audio Modules: Such as the EWM104-BT5125 based on QCC5125, which supports high-quality coding like aptX and is used in Bluetooth headsets and speakers.

    • Interface Conversion Modules: Such as the EWD104-BT57, which provides RS485/RS232-to-BLE conversion, easily connecting traditional industrial equipment to Bluetooth networks.

Typical Application Scenarios of BLE in the IoT

Combined with the "application scenarios" repeatedly described in the documents, BLE has penetrated into various fields:

  • Smart Wearables and Health: Smart watches, bracelets, blood pressure monitors, blood glucose meters, etc., use BLE’s low-power features to achieve long battery life and data synchronization with mobile phones.

  • Smart Home and Building Automation: Smart door locks, lamps, curtains, temperature and humidity sensors, security sensors, etc. Control and data collection are performed via direct mobile phone connection (slave mode) or through a gateway (master-slave integrated/Mesh).

  • Industrial Internet and Data Acquisition: Industrial sensors, instruments, and wireless transformation of PLCs. The low-power mode of the module (controlled via AT+SLEEP commands or WAKEUP pins) makes battery-powered field monitoring devices possible.

  • Asset Tracking and Indoor Positioning: Combined with iBeacon/Eddystone advertising protocols or BLE 5.1 direction finding functions, it is used for warehouse material management, indoor navigation in shopping malls, and hospital equipment tracking.

  • Smart Remote Controls and Accessories: Toy remotes, selfie sticks, keyboards, mice, etc., providing instant low-latency control.

BLE low-power Bluetooth technology, with its IoT-native genes, has become one of the core short-range wireless technologies connecting the physical and digital worlds through extreme power consumption optimization, flexible network topology, and continuously evolving technical standards. From EBYTE’s complete product line covering versions from 4.2 to 5.3 and functions from simple transparent transmission to complex Mesh, it can be seen that BLE technology is developing towards longer distance, higher speed, more precise positioning, lower power consumption, and stronger networking capabilities.

For developers, choosing BLE means choosing a mature technical path that balances performance, power consumption, and cost. Whether developing a simple smart single product or building a complex IoT system, a suitable solution can be found in the BLE ecosystem. With the Bluetooth Special Interest Group (SIG) continuously advancing new specifications such as LE Audio and Mesh models, BLE will undoubtedly play an even more indispensable role in the future landscape of the smart connection of everything.