Initiate connection from Arduino to remote device

Question

I am trying to achieve that my arduino-built device connects automatically to a device after it is switched on. The board is an Arduino Mini Pro and the bluetooth module is the Bluetooth Mate Silver (RN42). The devices are already paired, the bluetooth module is in slave mode, the remote device (in this case a normal laptop) is discoverable. I am using the SoftwareSerial library provided with the Arduino software.

Here is my setup:

void setup()
{
  Serial.begin(9600);  // Begin the serial monitor at 9600bps

  // bluetooth

  // set baud rate to 9600 
  bluetooth.begin(9600);  
  // start command mode
  bluetooth.print("$$$");
  // reply delay
  delay(100);
  // set to slave mode
  bluetooth.println("SM,0");
  // reply delay
  delay(100);
  // set device pin to 0403
  bluetooth.println("SP,0403");
  // reply delay
  delay(100);
  // connect to pixelsense
  bluetooth.println("C," + remoteMAC); // remoteMAC is a string with the mac address
  // reply delay
  delay(2500);
  // leave command mode
  bluetooth.println("---");
  // reply delay
  delay(100);
}

I read the command set of the RN42 and I think the commands are correct. I can connect to Arduino via bluetooth but the other direction isn't working. I also tried using the master mode or storing the remote mac in the flash instead of using a string. From the documentation it should be possible to initiate connections from the RN42, but I haven't quite found out how this works in details. Can anyone provide any help to solve my issue?

EDIT: The device does not seem to enter command mode at all. At least the flash lights don't indicate that. Is there anything wrong with the commands so that the command mode cannot be accessed?

xmashallax xmashallax · Accepted Answer · 2013-09-17T23:08:43

After nearly a week, I came across a solution. Actually it seems to be important that there is any program that accepts a bluetooth connection. I tried it the whole time with the Windows 7 Bluetooth dialog menu entry "Receive a file" but that did not work. So I used a third party program that listens for incoming connections and that actually worked. Basically everything I did was fine except for the missing connection listener.

Sometimes if I upload new code to the Arduino there is the problem that the connection cannot be established. This can be solved by removing and readding the bluetooth device.

The code for the RN42 Bluetooth Client above works. The library SoftwareSerial provided with the Arduino software is used.

Initiate connection from Arduino to remote device

4 Answers