BlueLink Gold Class-1 Bluetooth Modem

BlueLINK-Gold is a compact Class-1 Bluetooth Module (5V & 3V Compatible) from rhydoLABZ. The module is built with Voltage regulator and level converter required to interface with 5V & 3V3 Micros alike . It is only having 7 pins (Standard 2.54mm bergstrip) VCC,GND,TX,RX,CTS,RTS and RESET. Even it is having 7Pin,it requires only 4Pin (VCC,GND,TXD and RXD) for normal operation. The module is factory configured in Transparent Mode. So there is no command required for normal operation. These modems work as a serial (RX/TX) pipe. Any serial stream from 9600 to 115200bps can be passed seamlessly from your computer to your target. We’ve tested these units successfully over open air at 350ft (106m)!

This BlueLINK-Gold modem is fully compatible (Physical & Specification) with Famous BlueSMiRF-Gold made by SPARKFUN ,extra RESET pin available at connector. Certainly it is not a Clone , we redesigned the circuit with level conversion Buffer gates for added reliability.

This unit build with the Roving Network’s Bluetooth module RN41 and this unit uses an improved command set.This module can be powered from 3.3V up to 6V for easy battery attachment. All signal pins on the remote unit are 3V-6V tolerant. No level shifting is required.The board is already populated with level conversion buffer ICs. Do not attach this device directly to a PC serial port. You will need an RS232/USB to TTL converter circuit if you need to attach this to a computer.

Features

FCC Approved Class 1 Bluetooth® Radio Modem
SPP (Serial Port Profile) support
Extremely small radio – 0.15×0.6×1.9″
Breadboard Compatible
Onboard Status,Connected and Power LED
Very robust link both in integrity and transmission distance (100m) – no more buffer overruns!
Low power consumption : 25mA avg
Hardy frequency hopping scheme – operates in harsh RF environments like WiFi, 802.11g, and Zigbee
Encrypted connection
Frequency: 2.4~2.524 GHz
Operating Voltage: 3.3V-6V
Serial communications: 2400-115200bps
Operating Temperature: -40 ~ +70C
Built-in antenna
Dimensions: 51.5×15.8×5.6mm

Specification

Pin Diagram
Pin Details

Layout

How to Test?

1.Bluetooth configuring of BLueLink(GOLD) via PC:

The BLueLink GOLD is the most efficient Bluetooth TTL module that is based on Bluetooth modules from Roving Networks. BLueLink Gold is RN41 based .The speciality of Bluetooth modules from rhydoLABZ is that you can interface these with microcontrollers without any external hardware circuitry, let it be a controller with 3V3 logic level or a controller with 5v logic .You just need to give appropriate supply (3v3/5v) to the module.

Before interfacing Bluelink GOLD directly with a controller using its serial port, it would be better to first learn how the module actually works!The easiest way is by connecting it with a PC and passing AT commands. The module works at logic level of 3v3 or 5v , so in order to interface Bluelink GOLD with the system you should make use of a converter ,probably a USB to TTL (3v3/5v) converter or an RS232 to TTL converter. More preferable option will be to use a USB converter since RS232 ports are little obsolete and are not available in modern desktop systems and laptops. Hence it would be better to choose a TTL converter with USB option.

It is preferable to use a FTDI Breakout(3v3) or FTDI Breakout(5V) from rhydoLABZ, let it be 3v3 or 5v whichever be, it would be suitable with the Bluelink GOLD module.This breakout basically acts as a converter and is very compact and easy to use. The USB to TTL convertor can be easily installed by simple steps.

When we have a look at BLueLink (Gold), Six interfacing pins can be seen in the product namely CTS,RTS ,RX ,TX ,VCC ,GND and RST. VCC and GND form the supply for the module. Through the RST pin we can Reset the module if required.RX and TX pins are the serial communication pins available in the module for serially communicating in UART.CTS & RTS are the pins made available for Hardware flow control which we shall see later in this thread.

Make connections from the Bluelink GOLD module to the FTDI breakout as shown below:

Connect TX(module) to RX of FTDI Breakout and similarly RX(module) to TX of FTDI breakout and you can obviously give supply to the Bluelink GOLD module from the breakout by simply connecting VCC (breakout) to VCC(module) and make GND common. You can have a bunch of jumper wires to make suitable connections.After that interface the FTDI breakout with a PC using a USB miniB cable. When you reach this point all your hardware connections are complete. Now you can proceed with configuring the Bluetooth module by using a PC.

When you first connect your breakout you can view the COM port to which the breakout got selected in your PC in the Device Manager. For Example you can see the image below:
When connected the module you can see it got connected to COM38 as we can clearly observe in the above picture.
Now in order to communicate with module there is a terminal software like Realterm which provides systematic user interface options to communicate with any device via PC’s COMport. Hyperterminal will also work but Realterm is Recommended.

Using REALTERM

When you have connected the module to the FTDI breakout which in turn has been connected to the system, you can see a blue LED that glows constantly and remains stable when the module has been powered up, it is shown by the name PWR.
The status LED (Green) blinks continually with pauses ,which represents the mode in which the module is in.
When you have first powered up then this status LED blinks Two times a second indicating that it is in Startup/Config timer Mode. After the configuration timer has elapsed it comes to IDLE mode in which the status LED blinks once in a Second. This state is also used by the module to represent that the module is discoverable or is inquiring.
Now open realterm and follow the steps below:

Select the ANSI option from display as you can observe from the above picture.Now, when the module comes to your hand it is by default configured at 115200 baud rate. So select the appropriate baud rate as you can give in the leftmost top Baud option.
Keep all other settings as shown in the window like for parity and data bits…

After selecting the comport as 38 click on change.

Before exiting these options click Open. At this the port gets connected at 115200 baud rate to the FTDI breakout.Keep the hardware flow control also as none.Now click the Send option and you will be able to see the facilities described in the picture.

In order to test the connectivity of the module to the system we first send ‘$$$’ as shown in the picture, write it in that space provided and then click ‘Send ASCII ‘then the module enters Command mode and the status LED (green) starts blinking rapidly at the rate of 10times/s indicating that it has entered configuring mode.
Now whatever data you are trying to send to the module will be treated as commands and the module responds accordingly. All the commands whether it be data should be given at the same location where ‘$$$ ‘ was written or else you can click the window where CMD is written and start typing the characters directly there.
When you are finished you can return back to the earlier mode by giving command ‘—\r’ .’\r’ or the carriage return is a must as without it the module shall not respond to the command. Apart from ‘$$$’ all commands should be preceded with \r. Now you can proceed with rest of the commands as described in the datasheet….
For Example: You can view the current configuration of the Bluelink GOLD module by giving command ‘D\r’.Then the reply will be like ,as shown in the picture below:

In the beginning you can see ‘END‘ which is actually the result of a previous ‘—\r’ command and then after that ‘$$$’ was again given to Enter the command mode at which the modem replied with’ CMD‘.
Now we gave the command ‘D\r’ and modem replied with all its basic settings .We can observe that the Bluelink GOLD Module is by default in slave mode which means that it can be paired from an external Bluetooth device or a master and can be connected to it.

Now we have reached a situation in which we can search this module from other Bluetooth devices, Although the Bluelink GOLD is configured as slave we can also initiate a Bluetooth connection from it, and obviously it can also be discovered and connected from other Bluetooth devices in SPP profile.The serial port profile behaves as a wireless serial link, the data bytes that we send from a Bluetooth device are received at the other end like if we have connected a serial cable in between them.

The simplest way to begin is a USB Bluetooth dongle. You can connect it to your PC and make Bluetooth connectivity available. Here are some steps by which you can search for the Bluelink GOLD module which we already powered using the FTDI breakout described earlier.

First install the Bluesoleil software and Bluetooth dongle in your system.
Then open it you can see a window like this:

When you press the red button in the middle then the software displays status as ‘Searching for devices..’You can also do this by going to the view option and then by clicking Refresh services..
After the search is complete you can see our RN-42 based Bluelink GOLD module has been found out by Bluesoleil:

When it gets detected simply right click and give refresh services as shown above.. At this you will be able to view the status like shown below:

After that you can right click the RHYLABZ icon and click connect, if the module is not already paired it may ask a passcode and at this you can give the default set passcode as 1234 and then press OK.

Once connected you will be shown the above window and the Bluelink GOLD module will have its CNT led(orange) turned on when connected. Now see status by right clicking..

You can observe the COM port to which the SPP connection from Bluesoleil got connected.Select the very same Comport(COM7) in the terminal window that you wish to use in order to communicate with Bluelink GOLD.
Bluelink GOLD was connected to COM38 which we already know.Now what we have to do in order to test our Bluetooth connection?We will open a terminal with COM7 selected, in this, baud rate is not important as the communication is from the dongle.
And another terminal will be opened in which COM38 will be selected which we saw earlier, in this case giving appropriate baud rate is significant ,in our case it will be 115200 baud ,with other settings like parity none, data bits 8,stop bit 1 and hardware flow control also none .
Let us see some images relating to the data transfer.

It would be better to use Realterm for one COM and HyperTerminal for the other one because sometimes two Realterms may not work correctly, Or else you can first try with Realterms itself,If you are finding problems in opening a new Realterm with one Realterm already opened then you can switch to HyperTerminal.

Whatever data we type in one terminal will be reflected in the other one . You can also do by connecting the Bluetooth dongle to any other system and then initiating Connection from there.

Using hardware flow control in Bluelink GOLD :

Now if you make the CTS pin high during data transmission then the Bluelink GOLD module will not send any further data till it is cleared. So in this way you can buffer in the incoming data to the Bluelink GOLD over the Wireless link. This is the case when you don’t want the module to send data.

Usually RTS pin always remains low, it becomes high when it wants us not to send any more data, if its high then whatever data we send to Bluelink GOLD will not get transmitted over the wireless SPP link.

Such a situation rarely happens only in the case when we are using the module for high-end applications and you are sending a very large amount of data chunks over the wireless link. So when module again clears RTS pin we can send data to the module.

Initiating a Bluetooth connection from Bluelink GOLD

Till Now we were treating Bluelink GOLD as slave. When we configure it as master then the module cannot be discovered or connected from other Bluetooth devices ,it can only initiate one. In slave mode the module is connectable and discoverable that is how we were able to discover and connect the module from the Bluesoleil software but we can also make outbound connections from the module even when it is in slave mode this makes it unique when compared with other Bluetooth modules and the older version of Bluelink GOLD itself.
As now you have become familiar with Realterm so you can proceed with below steps:
To search a Bluetooth device when in slave mode simply give:
$$$
The module responses back with
CMD
Then start an inquiry session,give:
I\r and then press send ASCII.It shall reply with inquiry,COD=0.After sometime the number of Bluetooth devices that have been
found in the vicinity will be replied from the module with “found <number>”. Along with it we will be receiving the Bluetooth device’s address in the format may be after a little delay :
<Bluetooth address>,<Bluetooth device name>,<Device Class>
Store this remote address just found by giving command:
SR,<Bluetooth Address>\r
Module Replies with AOK
Now to initiate connection give C\r.
It replies TRYING
On connection you may not see any indication in your terminal the status of connection can be known by the CNT LED(yellow) on the module.
For more details regarding commands you can refer the AT command set and datasheets from here.

2.Testing BlueLINK-Gold with Arduino

Bluelink Gold Bluetooth module can be interfaced easily with Arduino board. Here we have used the board : Arduino Duemilanove for checking the Bluelink Gold Bluetooth Module. The connection diagram is shown below:

Following is a sample program showing the interface between Bluelink GOLD and Arduino:

/****************************************************************************************
 The following program turns the LED( 13th pin of Arduino board)  ON when letter 'O' or 
 'o' is pressed and turns OFF the same LED when 'F' or 'f' is pressed (slave mode) .
 BOARD   : Arduino Duemilanove
****************************************************************************************/

#include<string.h>
char string[30];
boolean sendata=false;

/**************************************************************************************
  Function    : setup()
  Description : Use it to initialize the module and setting the baudrate.
                The setup function will only run once, after each power up or reset
                of the Arduino board.
**************************************************************************************/

void setup()
{
 Serial.begin(115200);
 pinMode(12,OUTPUT);                                   //reset
 pinMode(13,OUTPUT);                                   //Onboard LED status
 digitalWrite(12,LOW);
 delay(20);
 digitalWrite(12,HIGH);
 delay(1000);
 Serial.print("$$$");                                 //For connection establishment
}

/************************************************************************************
  Function    : loop()
  Description : loops consecutively, allowing your program to change and respond.
                Use it to actively control the Arduino board.
************************************************************************************/

void loop()
{ 
   static int i=0;
   static char x;

  if(Serial.available()>0)
 { 
     x=Serial.read();
     if(x!='\r' && x!='\n')
     string[i++]=x;
     string[i]='\0';
     if(sendata==true)
    {
     if(x=='O'||x=='o')
     digitalWrite(13,HIGH);                         //LED on PIN 13 is turned ON
     else if(x=='F'||x=='f')
     digitalWrite(13,LOW);                          //LED on PIN 13 is turned OF
    } 
     if(i==3 && strcmp(string,"CMD")==0)
    {
     delay(1000);                                  // calling a delay
     Serial.flush();sendata=true;
     i=0;
    }

 }
     if(sendata==true)
    {
     delay(2000);
     Serial.print("BLueLink GOLD is sending data"); // Displays on the serial monitor 
    }  

}

/****************************************************************************************

The following program turns the LED( 13th pin of Arduino board) ON when letter 'O' or

'o' is pressed and turns OFF the same LED when 'F' or 'f' is pressed (slave mode) .

BOARD : Arduino Duemilanove

****************************************************************************************/

#include<string.h>

char string[30];

boolean sendata=false;

/**************************************************************************************

Function : setup()

Description : Use it to initialize the module and setting the baudrate.

The setup function will only run once, after each power up or reset

of the Arduino board.

**************************************************************************************/

void setup()

{

Serial.begin(115200);

pinMode(12,OUTPUT); //reset

pinMode(13,OUTPUT); //Onboard LED status

digitalWrite(12,LOW);

delay(20);

digitalWrite(12,HIGH);

delay(1000);

Serial.print("$$$"); //For connection establishment

}

/************************************************************************************

Function : loop()

Description : loops consecutively, allowing your program to change and respond.

Use it to actively control the Arduino board.

************************************************************************************/

void loop()

{

static int i=0;

static char x;

if(Serial.available()>0)

{

x=Serial.read();

if(x!='\r' && x!='\n')

string[i++]=x;

string[i]='\0';

if(sendata==true)

{

if(x=='O'||x=='o')

digitalWrite(13,HIGH); //LED on PIN 13 is turned ON

else if(x=='F'||x=='f')

digitalWrite(13,LOW); //LED on PIN 13 is turned OF

}

if(i==3 && strcmp(string,"CMD")==0)

{

delay(1000); // calling a delay

Serial.flush();sendata=true;

i=0;

}

if(sendata==true)

{

delay(2000);

Serial.print("BLueLink GOLD is sending data"); // Displays on the serial monitor

}

3. Testing BlueLINK-Gold module and PIC Micro-controller

Bluelink Gold Bluetooth module can also linked to PIC microcontroller. Here we have used PIC16f877A microcontroller for testing the Bluelink Gold Bluetooth module. The connections are clearly shown below:

Following is a sample program showing the interface between Bluelink GOLD and PIC16F877A:

/****************************************************************************************
The following program turns the LED( connected to RB3 of PIC16F877A)ON when letter 'O'
or 'o' is pressed and turns OFF the same LED when 'F' or 'f' is pressed (slave mode) .
****************************************************************************************/

#include<pic.h>
#include<string.h>
void USART(const char *USART);
#define  TxF  while(!TRMT);	
char Rx;
int OK=0;

int count=0;                                     
void main()
{
TRISB=0x00;
PORTB=0x00;                            //setting PORTB as output port
TRISC=0X80;
TXSTA=0X24;                                                    
RCSTA=0X90;
SPBRG=0X81;                            // setting baud rate as 9600
INTCON=0XC0;
PIE1=0x20;
USART("$$$\r\n"); 
while(1);                             //sending $$$ command
                                      //checking for OK received                                           
}

/****************************************************************************************
Function    : interrupt isr()
Description : interrupt service
****************************************************************************************/

void interrupt isr()
{
RCIF=0;
Rx=RCREG;
if (Rx=='C')	                       // Checking for the response of AT COMMAND					
OK=1;
if (Rx=='M')						
OK=2;

if (Rx=='D')
OK=3;

if(OK==3){
	if (Rx=='o'||Rx=='O')	       // LED is turned ON
         PORTB=0XFF;
	if (Rx=='f'||Rx=='F')	       // LED is turned 0FF
         PORTB=0X00;
	}

	}
}

/****************************************************************************************
Function    : USART(const char *USART)
Description : transmiting string of data
****************************************************************************************/

void USART(const char *USART)	
{	
	while(*USART!='\0'){
	TXREG=*USART;
	TxF;USART++;}	
}

/****************************************************************************************

The following program turns the LED( connected to RB3 of PIC16F877A)ON when letter 'O'

or 'o' is pressed and turns OFF the same LED when 'F' or 'f' is pressed (slave mode) .

****************************************************************************************/

#include<pic.h>

#include<string.h>

void USART(const char *USART);

#define TxF while(!TRMT);

char Rx;

int OK=0;

int count=0;

void main()

{

TRISB=0x00;

PORTB=0x00; //setting PORTB as output port

TRISC=0X80;

TXSTA=0X24;

RCSTA=0X90;

SPBRG=0X81; // setting baud rate as 9600

INTCON=0XC0;

PIE1=0x20;

USART("$$$\r\n");

while(1); //sending $$$ command

//checking for OK received

}

/****************************************************************************************

Function : interrupt isr()

Description : interrupt service

****************************************************************************************/

void interrupt isr()

{

RCIF=0;

Rx=RCREG;

if (Rx=='C') // Checking for the response of AT COMMAND

OK=1;

if (Rx=='M')

OK=2;

if (Rx=='D')

OK=3;

if(OK==3){

if (Rx=='o'||Rx=='O') // LED is turned ON

PORTB=0XFF;

if (Rx=='f'||Rx=='F') // LED is turned 0FF

PORTB=0X00;

}

/****************************************************************************************

Function : USART(const char *USART)

Description : transmiting string of data

****************************************************************************************/

void USART(const char *USART)

{

while(*USART!='\0'){

TXREG=*USART;

TxF;USART++;}

}

Resources

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Frequently Asked Questions(FAQ):

Q. How to save power during the usage of the module?
Ans. The module uses only a little power for transmission. To save a little more, it would be better to make it active only when data transfer is required.

Q. Will the device be capable to any system?
Ans. The device to which the module is associated would be capable of transferring data to any system with inbuilt Bluetooth. If the system lacks Bluetooth capability, it is advisable to connect a Bluetooth dongle to it.

Q. How to ensure that the devices are connected and ready for data transfer?
Ans. the LED’s in the module shows the connection status. This makes easy to ensure that the devices are linked.

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