Data logging of key presses

[Belen Lopez]

Hi,

I have a condition in my experiment that requires people to produce finger
taps for 20 seconds. What I would like to do is have a method that will
record all the finger taps that were produced in that time period. Ideally
I would like to have a clock running that will actually tell me when the
tapping started and when it stopped. However, my experiment is presented
orally to the subject, and they have to tap only on occasion that they do
not know the answer immediately. Therefore, I need to develop a sort of
counter that will be able to distinguish and able to log as new data the
next time someone taps in for 20 seconds.

I have access to E-prime response boxes, so I was thinking to use these
instead of the keyboard but either will be fine. 

Any help on how to go about setting this up will be extremely appreciated.

Maria