I have an HC-06 Bluetooth module connected to an Arduino UNO board to allow for the data received by the Ultrasonic sensor to be transferred to my PC via bluetooth and serial communication. I am using the Putty program to view the data. The thing is, my PC says that it has paired with the bluetooth and I was able to see the COM number but when I opened Putty and entered the COM number while choosing the option 'serial' an error box appears saying: Unable to open serial port.

The way I am currently connecting my bluetooth to the arduino board is:

RX->pin 10

TX->pin 11

GND->GND pin


I am sure that the sketch in the arduino for serial communication via bluetooth is right as I have tested the system yesterday and it worked. Only after a time (say like 5-10 min) the connection breaks and I cant seem to figure out the problem. Oh and the Arduino is being powered by USB if that matters.


If you have powered the BT module from 5v you may have fried it, I recall that the hc-06 module is 3.3v and 3.3v signal too.

  • 2
    The HC-06 vcc needs minimum power 3.6 to 6V, but it's the rx, tx pins that need 3.3 v output from the arduino Mar 17 '16 at 14:50

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