This shield has been specially designed to accommodate three different types of Bluetooth modules (HC-05, BLECC2541, BLE40), each of which is supplied already soldered on support (breakout board) compatible with the X-BEE format.
The shield has the purpose of adapting the voltage levels between Arduino working at 5V and the modules operating at 3.3V, providing a whole series of links with the various pins of the modules, depending on the function that you want to implement.
Through simple mini-jumpers, you can configure the necessary connections at the hardware level.
When it comes to serial communication, there are several wiring that allows you to talk to the Bluetooth module.
Our shield can be configured to let the Bluetooth module communicate directly with the PC using the USB / Serial converter of the Arduino board; dialogue with the Arduino microcontroller using the hardware UART module; from the microcontroller to the PC.

N.B. Arduino and the breakout board with Bluetooth modules are not included, see related products.

This project comes in kit. Some components have to be soldered to the included PCB.

The HC-05 module (not included - see related products)

Bluetooth module that uses the BlueCore4 CSR chipsets. It has 7 I / O ports, 8 Mbit of Flash memory for software storage and two modes of operation: through AT commands and in transparent mode. In transparent mode, it can be configured as a Master, Slave or Loopback, and can connect to other devices that support the SPP protocol. In the AT command mode, the user can configure the module and send commands. By checking the logic level of the PIO11 pin, the user can activate the working mode between AT and transparent command.

• USB protocol: V 1.1 / 2.0
• Frequency: 2.4 GHz ISM band
• Modulation: GFSK (Gaussian Frequency Shift Keying)
• Transmission power: about 4dBm, Class 2
• Sensitivity (BER): approximately -84dBm
• Max. Serial baud rate: 1382400bps, support for hardware flow control transfer
• Rate:
• - Asynchronous: 2.1 Mbps (Max) / 160 kbps
• - Synchronous: 1 Mbps / 1 Mbps
• Security: Authentication and encryption
• Support profiles: Bluetooth serial port (master & slave)
• Power supply: +3.3 Vdc 50 mA
• Working temperature: from -5 ° C to + 45 ° C
• Dimensions (mm): 27x13

The BLE CC2541 module (not included - see related products)

Bluetooth 4.0 (Low Energy) module compliant with ISM 2.4 GHz, master/slave operation mode with transparent data transmission, based on the Texas Instruments CC2541 chip with 256K of Flash memory and 8K RAM. It can be controlled through simple AT commands (via UART) or programmed with custom applications. Ideal for use in projects where a Bluetooth connection is needed, such as between microcontroller and PC. Power supply between 2 V and 3.6 Vdc.Dimension (mm): 27x13x1.6, weight: 5 grams. N.B. SMT assembly.

• 2.4 GHz ISM compliant Bluetooth 4.0 module (HM-10)
• It uses the Texas Instruments CC2541 SoC chip with 256K of Flash memory and 8K RAM
• Supports master and slave mode
• Standard RX gain: 19.6 mA
• TX -6 dBm: 24 mA
• Frequency: 2402 - 2483.5 MHz in 20 kHz steps
• Modulation and Data Rate: 1 Mbps, GFSK
• Number of channels: 40
• Output power: -23 to 4 dBm
• Receive sensitivity: -93dBm / -87dBm
• Stack: ATT, GATT, SMP, L2CAP, GAP
• Range: over 70 meters
• 10-bit ADC
• Serial interface: UART / SPI
• Wake-up interrupt, Watchdog Timer
• AES Security Coprocessor
• Power supply: between 2 V and 3.6 V
• VDD ripple: 100 mV max
• Current consumption (at 25 ° C with VDD = 3 V):
• - Power Mode 3 (External Interrupts): 0.4 uA
• - Power Mode 2 (SleepTimerOn): 0.9 uA
• - Power Mode 1 (3-μs Wake-Up): 235 uA
• - RX Standard Gain: 19.6 mA
• - TX -6 dBm: 24 mA
• - TX 0 dBm: -
• Operating temperature: from -40 ° C to + 85 ° C
• Dimensions (mm): 27x13x1.6

The BLE BM-S02 module (BLE40 - not included - see related products)

Bluetooth 4.0 (Low Energy) module compliant with ISM 2.4 GHz, master/slave operating mode with transparent data transmission, based on the Texas Instruments CC2540 chip with 256K of Flash memory and 8K RAM. It can be controlled through simple AT commands (via UART) or programmed with custom applications. Ideal for use in projects where a Bluetooth connection is needed, such as between microcontroller and PC. Power supply between 2 V and 3.6 Vdc. Dimensions (mm): 15,35x11,35x2.

• 2.4 GHz ISM compliant Bluetooth 4.0 module
• It uses the Texas Instruments CC2540 SoC chip with 256K of Flash memory and 8K RAM
• Supports master and slave mode
• Standard RX gain: 19.6 mA
• TX -6 dBm: 24 mA
• Frequency: 2402 - 2483.5 MHz in 20 kHz steps
• Modulation and Data Rate: 1 Mbps, GFSK
• Number of channels: 40
• Output power: -23 to 4 dBm
• Receive sensitivity: -93dBm / -87dBm
• Stack: ATT, GATT, SMP, L2CAP, GAP
• Range: over 70 meters
• 10-bit ADC
• Serial interface: UART / SPI
• Wake-up interrupt, Watchdog Timer
• AES Security Coprocessor
• Power supply: between 2 V and 3.6 V
• VDD ripple: 100 mV max
• Current consumption (at 25 ° C with VDD = 3 V):
• - Power Mode 3 (External Interrupts): 0.4 uA
• - Power Mode 2 (SleepTimerOn): 0.9 uA
• - Power Mode 1 (3-μs Wake-Up): 235 uA
• - RX Standard Gain: 19.6 mA
• - TX -6 dBm: 24 mA
• - TX 0 dBm: -
• Operating temperature: from -40 ° C to + 85 ° C
• Dimensions (mm): 15,35x11,35x2

A practical example of use

A possible application could be to monitor the temperature and humidity of a room using a smartphone. In the Android app store, there are several applications that allow, with simple drag and drop, to create their own personalized interface with which to interact with Arduino via Bluetooth. Among those in the store, we chose Bluetooth Electronics that seemed to us the most complete and obviously free. The app already provides ready screens and a short tutorial for the Arduino configuration, the reference site is http://www.keuwl.com.

The mechanism of operation is very simple, you edit the interface by adding the desired widgets and then you associate their display to the receipt of a string. From the Arduino side we used a DHT11 module that allows you to easily detect ambient temperature and humidity, at regular intervals these values will be sent via Bluetooth to the smartphone as strings:

Serial.
print ("* T" + String (temp) + "*") e
Serial.print ( "H *" + String (humidity) + "*").

For the functioning it is necessary that the microcontroller of Arduino communicate with the Bluetooth module, therefore we will close with a jumper the pin JTX with D0 and JRX with D1; to avoid the conflict with the Arduino USB / serial converter it may be necessary to remove the jumpers during the programming phase.
If, on the other hand, we want to activate outputs, simply add buttons or switches to the working screen and associate their click with the sending of a character; Arduino side would be enough to read the characters received on the serial and activate the output in correspondence:

if (Serial.available ()) {
char ch = Serial.read ()
if (ch == 'a') digitalWrite (OUT, HIGH);
if (ch == 'A') digitalWrite (OUT, LOW);
}