Project Background 

With the rapid development of the smart hotel industry, traditional mechanical keys and IC card door locks are gradually replaced by intelligent solutions due to high management costs and limited user experience. A chain hotel company plans to deploy 5,000 sets of smart door lock systems, with core requirements focusing on low power consumption, low complexity, and high reliability. Specific functions include:

1. Timed broadcasting mechanism: The door lock must actively send Bluetooth broadcast signals periodically to ensure quick detection by mobile phones.

2. Bidirectional data transmission: Support Bluetooth connection establishment between mobile phones and door locks, enabling encrypted key transmission and real-time feedback of unlocking results (success/failure).

3. Long-term stable operation: The module must achieve low-power standby on battery power, meeting the 1-2 year battery life requirement in hotel scenarios while simplifying post-maintenance complexity.

Advantages of E104-BT5032A/B Modules

The E104-BT5032A/B series Bluetooth modules are designed based on the Nordic nRF52832 chip, optimized for low-power IoT scenarios. Their core features perfectly match hotel door lock requirements:

1. Ultra-Low Power Consumption for Extended Battery Life

• Broadcasting mode power consumption: Supports customizable broadcast intervals (adjustable from 100ms to 10s), with a minimum broadcast current of only 2.5μA. With two AA batteries and 100 daily mobile wake-ups, it achieves over 2 years of battery life.

• Connected mode power consumption: Average current during data transmission is <10mA, and a single unlocking process (including connection, key transmission, and feedback) takes <3 seconds, resulting in negligible power consumption.

2. Simplified Development Process and Reduced Integration Difficulty

• AT command quick configuration: No complex Bluetooth protocol development is required. Broadcast parameters, encryption methods, and data transparent transmission modes can be set via AT commands, and the door lock MCU can communicate directly through the UART interface.

• Built-in security mechanisms: Supports AES-128 encryption algorithm and device whitelist function to prevent unauthorized device connections. Key transmission is fully encrypted to protect hotel user information security.

3. High-Reliability Communication for Complex Environments

• Bluetooth 5.0 BLE protocol: Transmission distance reaches 30 meters (in open environments) and maintains stable connections after penetrating 1-2 walls, meeting communication needs in hotel corridors and rooms.

• Fast reconnection mechanism: The module supports connection state retention and fast reconnection (reconnection time <500ms), avoiding unlocking failures due to signal fluctuations.

System Architecture and Workflow

1. Hardware Architecture Design

• Core components: E104-BT5032A/B module + low-power MCU (e.g., STM32L0 series) + electromechanical lock body + lithium battery pack.

• Interface connection: The module communicates with the MCU via UART. The MCU controls the lock body drive circuit and monitors door lock status (locked/unlocked) via GPIO.

2. Complete Workflow

(1) Timed Broadcasting Phase

The module defaults to low-power broadcasting mode, sending broadcast packets containing device IDs at preset intervals (e.g., once per second). After scanning the signal, the mobile APP parses the device information and displays the "unlockable" status.

(2) Mobile Connection and Key Transmission

• The user clicks "Unlock" on the APP, and the mobile phone initiates a Bluetooth connection. The module wakes up the MCU (via UART interrupt or GPIO signal) upon receiving the request.

• After connection establishment, the mobile phone sends a dynamic key (generated based on timestamp + device ID) through an encrypted channel, which the module transparently transmits to the MCU for authorization verification.

(3) Unlocking Result Feedback

• If the MCU verifies the key successfully, it drives the lock body to perform the unlocking action and sends an "unlock success" command back to the mobile phone via the module, prompting success on the APP.

• If the key is invalid or the lock body malfunctions, the MCU returns a "failure" command, prompting the user to contact the front desk. The module optionally records exception logs.

Solution Value and Implementation Recommendations

1. Core Value for Chain Hotels

• Reduced operating costs: Eliminates card production and distribution processes, reducing consumable and labor costs. Supports remote key issuance, allowing new users to check in without waiting at the front desk.

• Enhanced user experience: Mobile phones serve as keys, avoiding the inconvenience of forgotten room cards. Unlocking response time is <3 seconds, ensuring convenient operation.

• Data-driven management: The module records unlocking times and device status, providing hotel room usage data analysis.

2. Implementation Recommendations

• Module selection: E104-BT5032A (standard version) is suitable for most scenarios, while E104-BT5032B (enhanced version) supports external antennas and is recommended for metal doors with strong signal shielding.

• Testing and verification: Conduct high-low temperature (-20℃~60℃) and signal interference tests before mass deployment to ensure stability in complex hotel environments.

• Firmware updates: Reserve OTA upgrade interfaces to facilitate future module firmware updates via mobile APP and expand functions (e.g., adding NFC dual-mode unlocking).

  
  

The E104-BT5032A/B modules, with their core advantages of "low power consumption, easy integration, and high reliability," perfectly meet the intelligent transformation needs of chain hotel door locks. Through Bluetooth 5.0 technology and encrypted communication mechanisms, they ensure convenient user unlocking and efficient hotel management, providing a stable and cost-effective wireless communication solution for 5,000-door lock projects. It is recommended that customers prioritize small-batch (100 sets) pilot testing to verify real-world performance before full-scale promotion.