Hi Hossain.

If its resonant, then all you need is a circuit, like a Pierce Oscillator to start the transducer and stop it under computer control. The processor does nothing except demand the transducer to start, and then tell it to stop.

You will need fairly powerful devices in the oscillator too, ultrasonic SONAR transducers take a lot of power !

Don't fall for the trick of using simple logic gate chains to start the oscillator, for this appliaction they are rarely reliable.

Steve