I have connected the Hc05 to my uno like the following 5v->5v, gnd->gnd, tx->rx. I have not connected the tx pin of hc05 to rx pin of uno since i only need one way communication. When i connect my phone to the bluetooth and send some data for some reason the uno does not respond to it by blinking the rx led. Also nothing shows up on the serial monitor of the pc. But when i connect the same module to my pc through a usb to ttl converter, the module works fine. When i upload a program to the uno the rx tx led's flash but not when i use the module. Does anybody know whats wrong?
I found a temporary solution by using the SoftwareSerial library. But the hardware rx tx still doesnot seem to work.
Have you tried connecting the HC-05 Tx to Rx?
The RX LED is controlled by the Serial-to-USB converter chip, not by the AtMega328 chip. When you are not using the Serial-to-USB converter chip, because you are connecting directly to the AtMega328 chip, any expectation that the RX or TX LEDs will blink is misguided.