E104-BT51 is a serial to BLE Bluetooth slave module based on Bluetooth protocol version 5.0, which is small-sized, low power consumption, and works in the 2.4GHz frequency band. E104-BT51 module is a serial to BLE Bluetooth module developed by Chengdu Ebyte Electronic Technology Co., Ltd. based on TI CC2640R2F chip.
| Parameter | Specification |
| Model | E104-BT51 |
| Core Chip (IC) | TI CC2640R2F |
| Bluetooth Version | BLE 5.0 (Bluetooth Low Energy) |
| Frequency Band | 2.402 ~ 2.480 GHz (ISM Band) |
| Transmission Distance | 75m (at 0dBm in clear and open environment, height 1.5m) |
| Transmitting Power | 5 dBm |
| Receiving Sensitivity | -99 dBm (at 250kbps air rate) |
| Communication Interface | UART Serial Port |
| Module Role | BLE Slave / Beacon / iBeacon |
| Dimensions | 17.5 * 28.7 mm |
| Antenna Type | PCB Antenna (50Ω Impedance) |
| Package Type | SMD |
| Supply Voltage | 1.8V ~ 3.6V DC (≥3.3V ensures full output power) |
| Sleep Current | 29.93 μA (Default sleep broadcasting mode, 1s interval) |
| Operating Temperature | -40°C to +85°C |
| Manufacturer | CDEBYTE |
| RF Parameter | Value | Remark |
|---|---|---|
| Frequency [MHz] | 2402~2480 MHz | ISM band |
| Transmitting power | 5 dBm | - |
| Receiving sensitivity [dBm] | -99 dBm | Air rate is 250k bps |
| Distance | 75m（0dBm） | Clear and open environment, height 1.5m (only 75m can be tested by the host) |
| Hardware Parameter | Value | Remark |
|---|---|---|
| Size | 17.5*28.7 mm | - |
| Antenna | PCB | 50Ω Impedance |
| Communication interface | UART | - |
| Package | SMD | - |
| Electronic parameter | Min | Typ | Max | Unit | Remarks |
|---|---|---|---|---|---|
| Voltage supply [V] | 1.8 | 3.3 | 3.6 | V | ≥3.3 V ensures output power |
| Communication level [V] | - | 3.0 | - | V | For 5V TTL, it may be at risk of burning down |
| Sleep broadcasting current(default) | - | 29.93 | - | uA | Broadcast interval is 1s |
| Wake-up broadcasting current(default) | - | 1581 | - | uA | Broadcast interval is 1s |
| Wake-up no broadcasting current(default) | - | 1570 | - | uA | - |
| wake-up connection current(default) | - | 2301 | - | uA | Connection interval is 1s |
| Sleep connection current(Default) | - | 259.1 | - | uA | Connection interval is 1s |
| Operating temperature [℃] | -40 | - | +85 | ℃ | - |
Application Scenarios
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Smart Healthcare & Medical Wearables: Ideal for compact, battery-powered medical devices such as wireless heart rate monitors, pulse oximeters, and smart thermometers. The ultra-low sleep current (29.93 μA) of the TI CC2640R2F chip dramatically extends battery life, while BLE 5.0 guarantees stable wireless data transmission to medical apps on smartphones.
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Industrial Sensor Data Acquisition: Acts as a wireless bridge for legacy industrial sensors with UART interfaces. It allows environmental sensors (temperature, humidity, vibration) to transparently transmit telemetry data to a centralized Bluetooth gateway or edge controller over a 75-meter line-of-sight range without complex wiring.
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Smart Home Access Control & Keyless Entry: Perfect for integration into smart locks, biometric door handles, and home automation control panels. By leveraging the secure BLE 5.0 protocol and low-latency wake-up capabilities, it enables encrypted, hands-free authentication and control via mobile devices when a user approaches.
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Warehouse Asset Tracking & Proximity Marketing: Can be configured as an iBeacon/Beacon transmitter for precise indoor positioning and asset management systems. Deployed across warehouses or retail environments, it broadcasts unique IDs continuously to track high-value inventory or push proximity-based notifications to shoppers' smartphones.
Customer FAQ
Q1: Can the E104-BT51 module be configured to work as a Bluetooth master device? No, the E104-BT51 is hardcoded and optimized exclusively as a BLE Bluetooth slave device (serial-to-BLE slave). It is designed to be searched for, discovered, and connected to by Bluetooth master hosts such as smartphones, tablets, PCs, or designated Bluetooth master modules.
Q2: How does the module achieve such a low power consumption in battery-powered applications?
The module utilizes advanced power management features native to the TI CC2640R2F architecture. In its default sleep broadcasting mode with a 1-second broadcast interval, it consumes only about 29.93 μA. When it stops broadcasting entirely in deep sleep, the current consumption drops even further, maximizing the operational lifespan of coin-cell batteries.
Q3: How do I change the default settings like the Bluetooth name, baud rate, and broadcasting interval?
You can seamlessly configure all major network and hardware parameters using standard AT commands. Simply connect the module's UART pins to a PC via a USB-to-TTL converter, open a serial debugging assistant, and send the designated AT commands when the module is in its configuration/wake-up state.
Q4: Is the logic level of the communication interface compatible with 5V microcontrollers?
The typical communication level for the E104-BT51 UART interface is 3.0V. It is highly recommended to use a level shifter or voltage divider if you are connecting it directly to a 5V TTL microcontroller (such as traditional Arduino boards) to prevent the risk of overvoltage damage to the chip.
