Hi Igor,
I boyght a handy gadget a couple of months ago, it is a 11 input 10 bit ADC. It plugs into printer port on your pc and will graph, record any anylogue signal well beond yours, it cost ~ $120.00.
The type of transducer to use I am not sure, perhaps a pietzo crystal or an old converter off an old cleaner.
Here is a phone number of Branson UK they will know, if when you ring them ask to speak with Dawn and tell her that I said to ring and ask to speak to the guy who works on the cleaners who smokes a pipe. I was working with them a few weeks ago and I just cant remember his name.
Branson UK = 44-208 561 4422
Hope this is of some help Mark Fitzgerald.
PS if you cant ring them E-me & will find out for you.