Need Creative Input

I have incoming pulses about 5 VDC high, maybe 50 ms wide, and anywhere from 0.5 s to 30 s periods (time between). I need to measure that "time between" (the fuction Timer works well with 1/64 sec accuracy in my Desktop XP and 1/256 sec in my Vista Laptop).

I am trying to do this in Excel VBA, and I suceeded in writing a good deal of it simulating a pulse (the event) with either a manual command button click or in a loop with a random period. I am happy with it because it records the data in cells and plots them in a chart.

So my brain is about to explode because I can not figure out an inexpensive way to find the leading edge of the pulses. I have bought several expensive analog/digital modules/software from various dealers (found a great one for $25 with chart recorder software), but I can't read my signal into Excel.

So, I have a signal that is either High (1, True), or (most-of-the-time) Low (0, False). How, oh, how do I detect it so that I can check it again (hopefully, at least every 4 to 10 ms). I was thinking input by USB data pin, the microphone input, a joystick button press, any way that allows a real-time data read and incorporation into my program flow.

Solution contributors? I am not looking to talk to an instrument, just hear it singing to me. :banghead: