Junk values while reading from bluetooth serial port in linux PC from HC 05

I have an arduino board that is connected to MPU6050 motion sensor and HC 05 bluetooth module. The target is to acquire the motion sensor data via blueooth into my ubuntu laptop. I have successfully paired my ubuntu laptop with HC05 bluetooth module. The data that I get from the minicom is junk.

For the arduino + MPU6050 + HC05 set up I use the code named firmware500.ino at arduino-mpu6050-hc05 data aquisition. I had modified the code to get ascii readable values as suggested by the author.

The bluetooth in the linux PC is set using the steps at : bluetooth-serial-setup-linux.

To get the serial data I tried minicom with setting 1152008N1, no flow control.

I set the baudrate on the HC05 using AT commands to 115200,0,0.

I dont understand why I am getting junk values. The author of the arduino claims that the code works fine. So I guess the error is either in the minicom setting or the baudrate setting in the HC05.

I have successfully paired my ubuntu laptop with HC05 bluetooth module.

This only means that you have paired and made connection between bluetooth and PC. It does not mean that Bluetooth and Arduino are properly talking to each other.

The data that I get from the minicom is junk.

In the link, two things are noteworthy - you are using pins 10,11 for the serial connection, which implies you are using software serial, and a baud rate of 115200 is alluded to. Software serial at 115200 is not a good idea, and probably explains the junk. You might slow it down to a maximum of 38400, or get rid of software serial altogether and use hardware serial, pins D0,D1, @ 115200 instead. Since hardware serial is not used by the other device, and (I assume) you have actually gone to the trouble of properly reconfiguring the HC-05, the second option must be pretty persuasive.

I just changed the connections of the HC05-arduino. I connected Tx of Hc05 to Rx of arduino and vice versa. Then opened minicom and voila! I could read the data. I had setup HC05 baud rate to 115200,0,0 using AT commands. Minicom settings to 1152008N1, no flow control.

Hi, im face the similar problem, when i try to communicate between two modules HC-05 (Master & Slave - Configured using AT commands) and i use bray terminal to transfer data between them.

Junk value is received.

niyamraj: Hi, im face the similar problem,

You need to post your program code and a diagram (NOT Fritzing, thank you) showing how you have everything connected.

What PC operating system are you using and what terminal program are you using on the PC?