After several week of waiting for the parts I finally started to work on the software. Bad choice!! I should've done the code writing from the beginning of the course little by little. Anyway I am glad that I managed to achieve functionality at least. Now I have to just trim the code and assemble on a copper board.

The radio link works OK (after some hard work due to some wrong settings in the Hyperterminal :) used for debugging the serial communication). Pressure sensor work great, motor works fine, the only problem that I have is that the data transmission is quite slow and it reflects in the movement of the shaft of the stepper. It is a choppy linear motion, but I guess that the inertia in moving through the water will dampen the jerks in the motion, if any.

Another Picture