The OpenELAB HC-08 Bluetooth module is a digital transmission module based on the Bluetooth Specification V4.0 BLE protocol.
Its wireless frequency band is 2.4GHz ISM, using GFSK modulation.
The default transmit power is 4dBm, with a receive sensitivity of -93dBm.
This module is compatible with Android and Apple systems. In open environments, it can communicate with iPhone 4s and achieve ultra-long-distance communication up to 80 meters.
It features a status indicator, allowing users to directly see the Bluetooth connection state.
Built on the TI CC2540F256 chip, it comes with 256K bytes of memory and supports AT commands.
Users can change roles (master/slave), adjust baud rate, modify device name, and configure other parameters for flexible use.
Features
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Working voltage: DC 5V
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Working frequency band: 2.4G
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Air speed: 1Mbps
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Communication interface: UART3.3VTTL level
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Antenna interface: built-in PCB antenna
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Sleep current: 0.4μA
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RSSI support: not supported
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Receive sensitivity: -93dBm@1Mbps
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Communication level: 3.3V
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Bluetooth version: V4.0
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Modulation method: GFSK
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Transmit power: 4dBm (default)
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Reference distance: 80m
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Working temperature: -25℃ to +75℃
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Working humidity: 10% to 90%
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Storage temperature: -40℃ to +85℃
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Working current (excluding LED)
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Host not connected / connected: 21mA / 9mA
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Slave MODE0, not connected / connected: 8.5mA/9mA
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Slave MODE1, not connected / connected: 6μA ~ 2.6mA / 1.6mA
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Slave MODE2, not connected / connected: 0.4μA/1.6mA
HC-08 Pin Definitions
| Pin | Definition | I/O Type | Description |
|---|---|---|---|
| 1 | TXD | Output | UART output, 3.3V TTL level |
| 2 | RXD | Input, weak pull-up | UART input, 3.3V TTL level |
| 3 | NC | — | Not connected |
| 4 | NC | — | Not connected |
| 5 | NC | — | Not connected |
| 6 | DC | Input | Debug clock |
| 7 | DD | Input/Output | Debug data |
| 8 | P2.0 | Input, weak pull-up | Not connected |
| 9 | P1.7 | Input, weak pull-down | Not connected |
| 10 | P1.6 | Input, weak pull-down | Not connected |
| 11 | nRST | Input, pull-up | Module reset pin, low level ≥10ms for reset |
| 12 | VCC | Input | 3.3V DC power supply, ≥100mA current |
| 13 | GND | — | Ground |
| 14 | LEDCON | Input | LED control pin (Note④) |
| 15 | P1.4 | Input, weak pull-down | Not connected |
| 16 | P1.3 | Output | LED output (Note①) |
| 17 | P1.1 | Output | Link indicating (Note②) |
| 18 | P1.2 | Input, weak pull-down | Master module clear memory (Note③) |
| 19 | P1.0 | Input, weak pull-down | Not connected |
| 20 | P0.7 | Input, weak pull-up | Not connected |
| 21 | USB_D- | — | Not connected |
| 22 | USB_D+ | — | Not connected |
| 23 | P0.6 | Input, weak pull-up | Not connected |
| 24 | P0.1 | Input, weak pull-up | Not connected |
| 25 | P0.5 | Input, weak pull-down | Not connected |
| 26 | P0.0 | Input, weak pull-up | Not connected |
| 27 | VCC | Input | 3.3V DC power supply, ≥100mA current |
| 28 | GND | — | Ground |
| 29 | RXD | Input, weak pull-up | UART input, 3.3V TTL level |
| 30 | TXD | Output | UART output, 3.3V TTL level |
Electrical Characteristics
| Parameter | Test Condition | Representative Value |
|---|---|---|
| Working Voltage | - | DC 2.0V ~ 3.6V |
| Working Current (without LED) | Master: Not connected / connection | 21mA / 9mA |
| Slave MODE0: Not connected / connection | 8.5mA / 9mA | |
| Slave MODE1: Not connected / connection | 6μA ~ 2.6mA / 1.6mA | |
| Slave MODE2: Not connected / connection | 0.4μA / 1.6mA |