Pair HC05 BT Modules

Steps taken from comments on an Amazon listing for DSD devices:

I bought two of these to allow me to communicate between 2 arduinos. I had googled a little and it seemed simple enough from the examples I had seen, but once I got the chips I discovered none of the examples I found on-line worked. That’s where the support desk from DSD came in, these guys were great, I explained what I wanted to do and they helped me every step of the way, I’m not sure I would have gotten them working without the support desk’s help.
So if anyone wants to send data between two arduinos using these blue tooth chips here are the steps I followed

Step 1 To wire up the blue tooth to the arduinos follow the instructions on the following site, I also found arduino libraries help which controlled the serial communication ( I could not get the normal Tx Rx pins to work)
However the bluetooth commands listed on this site did not work for me, that is where DSD came to my rescue.

Step 2 To enter the AT command mode (where you define setting on the chip) press the button on the right hand side of the chip just above the pin as you are powering the chip on, if the chip enters command mode the led will flash slowly.

Step 3 Once in command mode select one chip to be the slave and one to be master
AT+ROLE=0 (Slave mode)
AT+ROLE=1 (Master mode)

Step 4 Set names for both chips
AT+NAME= name
AT+NAME? should give you the name back but didn’t work for me, so instead I confirmed the name using an android phone ( note devices in master mode will not show up in a scan)

Step 5 Set password
The default is 1234 and you could leave it at that if you really want but probably better to change it
AT+PSWD? will return the password
Make sure to set the same password on both devices

Step 6 find device address
Record the value for both master and slave

Step 7 on both devices do the following
and on the master
AT+BIND = slave address
on the slave
AT+BIND = master address

Step 8 both cycle both devices do not press the button to put them in command mode

They should now connect to each other the led will start to flash rapidly this is them in pairing mode and once they pair the led will do a double flash once every couple of seconds.

On final thing I had to set the BTserial on the arduinos to 38400 not 9600.