Arduino Hands-on-BT05 Bluetooth 4.0BLE Module

AT09 Bluetooth 4.0BLE Module Features:

Usage requirements:

For Apple devices: Compatible with iPhone 4S and above, running on iOS 6 and above.

For Android devices: Requires Android version 4.3 or higher, with Bluetooth version 4.0.

• The core module uses the BT05 module, with interface pins including VCC, GND, TXD, RXD, and STATE. An additional LED status output pin is reserved for indicating the Bluetooth connection status, allowing the microcontroller to determine if the Bluetooth connection is established.

• LED indicator displays the Bluetooth connection status: Flashing indicates no Bluetooth connection, steady light indicates Bluetooth connected and port opened. The STATE pin outputs high level when connected, low otherwise.

• Setting the module as master mode: The module is configured as a master or slave module via software. Send AT+ROLE1 command through serial communication (CR or \r\n), upon receiving "OK," the setting is successful with the LED blinking rapidly. Connecting the master module to a slave module requires specific AT commands (refer to the BT05 AT command set).

• Onboard 3.3V LDO, input voltage range 3.6-6V, strictly prohibit exceeding 7V.

• Interface operates at 3.3V, can be directly connected to various microcontrollers (e.g., 51, AVR, PIC, ARM, MSP430). Even 5V microcontrollers can be connected without needing MAX232 or passing through MAX232!

• Effective range in an open area is 7-10 meters, connectivity beyond 10 meters is possible but not guaranteed in terms of connection quality.

• Once paired, functions as a full-duplex serial port without requiring knowledge of Bluetooth protocols, supporting common communication format of 8 data bits, 1 stop bit, no parity bit. Only this format is supported, does not support other formats.

• Before establishing a Bluetooth connection, allows setting baud rate, name, pairing password using AT commands. Configured parameters are saved even after power loss. Automatically switches to transparent mode after Bluetooth connection is established.

• Compact size (3.57cm*1.52cm), factory soldered for quality assurance. Wrapped in transparent heat shrink tubing for dust prevention, aesthetics, and some static protection capability.

• This link acts as a slave device, compatible with various Bluetooth-enabled computers, Bluetooth hosts, most Bluetooth-equipped smartphones, PDAs, PSPs, and other smart terminals. Slave devices cannot pair with each other.

Module Wiring

Input Voltage: 3.3V/5V, only one power supply group is needed.

Built-in level conversion function.

If communicating with a Bluetooth module using a 5.0V MCU, power the 5.0V power port, and the logic levels for RX and TX are 5V.

If communicating with a Bluetooth module using a 3.3V MCU, power the 3.3V power port, and the logic levels for RX and TX are 3.3V.

For RX, connect the Bluetooth module's serial receive end to the MCU's TXD.

For TX, connect the Bluetooth module's serial transmit end to the MCU's RXD.

GND, ground terminal for power supply negative pole.

3.3V, 3.3V power supply at the power end.

5V, 5V power supply at the power end.

Module Usage Tips

• The MLT-BT05 4.0 Bluetooth moduleoperates in the 2.4GHz wireless frequency band, and should try to avoid various factors that may affect wireless transmission. Please pay attention to the following points:

• Avoid using metal for the product casing surrounding the Bluetooth module. If using a partially metal casing, try to keep the antenna part of the module away from the metal part as much as possible.

• Metal connecting wires or screws inside the product should be kept as far as possible from the antenna part of the module.

• Place the module's antenna part close to the edges of the PCB, avoiding placing it in the middle of the board. Make sure there is a clearance milled under the antenna on the PCB, parallel to the direction of the antenna, without copper pads or traces. Directly exposing the antenna part outside the PCB is also a good option.

• Cover the area under the module with a large GND plane as much as possible, and extend the routing towards the outer perimeter.

• It is recommended to use insulated materials for isolation at the module mounting position on the substrate, such as placing a whole block of silkscreen (Top OverLay) at that position.

Important Information (Vital)

TXD: Transmitter, generally refers to one's own transmitting end, normal communication requires connection to another device's RXD.

RXD: Receiver, generally refers to one's own receiving end, normal communication requires connection to another device's TXD.

During normal communication, your own TXD always connects to the other device's RXD!

Loopback Test: In normal communication, RXD is connected to another device's TXD. Therefore, if you want to receive data sent by yourself, namely self-transmission and reception, connect your own TXD directly to RXD. This is used to test whether the sending and receiving are functioning correctly. It is the fastest and simplest testing method. When troubleshooting, this test should be done first to determine if there is a product malfunction, also known as a loopback test.

Bluetooth 4.0 BLE

Bluetooth has gone through 8 versions of updates so far: 1.1, 1.2, 2.0, 2.1, 3.0, 4.0, 4.1, and 4.2. Between versions 1.x and 3.0, we refer to it as traditional Bluetooth, while Bluetooth starting from version 4.x is known as Bluetooth Low Energy (BLE). Of course, the 4.x version of Bluetooth is backwards compatible. Android phones must have a system version of 4.3 or above to support BLE API. Compared to traditional Bluetooth, Bluetooth Low Energy boasts faster transmission speeds, wider coverage, higher security, shorter latency, and lower power consumption, among other advantages. (Most wearable devices nowadays use BLE Bluetooth technology.)

The communication methods between traditional Bluetooth and Bluetooth Low Energy also differ. Traditional Bluetooth generally uses the socket method, while Low Energy Bluetooth utilizes the Gatt protocol for implementation.

Key Advantages:

Low energy consumption: runs on standard organic batteries and can operate for up to a year or even several years; low cost; full compatibility achievable.

Speed supports data transfer of up to 1M, minimizing interference with 4G to the maximum extent.

More intelligent: can complete data transmission within 3 milliseconds at most.

Enhanced security: employs encryption algorithms, providing encrypted and authenticated data packets. Therefore, the advantages of Bluetooth 4.0 encompass three specifications in one, combining the technologies of traditional Bluetooth. The biggest difference compared to version 3.0 lies in the significantly lower power consumption of 4.0, which is reduced by 90% compared to older versions. With Bluetooth technology evolving from traditional areas like smartphones, gaming, computers, and cars towards new fields such as the Internet of Things and healthcare, user demands are increasing. Version 4.0 strengthens data transmission technology while emphasizing low energy performance.

Open-source code

Experimental Setup Image