I am trying to set up an experiement to measure period doubling in a leaky tap. My plan was to just have a speaker input to a computer (through the com port I assume) to register drips into some container. My web searchs for how to wire the two wires from a speaker to any port on the copmuter have so far been fruitless. I was wondering if anyone here has ever set up an experiment hooked to their computer without labview and some sort of external card made specifically for the purpose. I am hoping to do this on the cheap. Maybe I should just get a microphone and plug it into the sound jack, but I am not sure how to take that signal to a nice data file I can look at with matlab or something. Any links/advice would be gratly appreciated.