Arduino-Bluetooth HC-05 Android app blueterm connection for chatting I want to communicate between an arduino and an Android phone that has an Android app blue term. I connected HC-05 with Arduino using software serial and I connected the hc05 as a device with the android app. I am able to send data ( data as in message) from Android to Arduino but I am unable to send message from arduino to Android though I have given .write() command to Bluetooth connected.

Is it such that the Android app does not show the received message? Or there is some master-slave configuration issue? Do I need to configure HC-05 in master mode? It was configured in slave mode by default when I had connected it to Android app.
Its totally Normal. You must be doing something wrong. It has happen to my Arduino Code a lot of times. try following:


Try interchanging you Tx and Rx Pin Positions. (This happens all the time).
Try connecting using default Serial and using Pin 1 and Pin 0 as Tx/Rx. (In this case remember to unplug the Tx/Rx Pins while running code.)
Try using just basic Serial.Write() function in beginning.