Two choices, depending on details you didn't tell.
1. Write your own dedicated keyboard driver, that implements this filtering.
2. Make your application program such, that it reads single characters from the input and filters them according to your timing rules.
Kees
I need a program that takes a key on the keyboard and requires say for instance a 2 second delay after the previous press to recognize onto the computer as a keystroke. So you can keep pressing it, but once you stop for 2 seconds it recognizes the FIRST keystroke then you keep pressing until you stop for two seconds again then it will recognize the first again and so on. Only thing the program has to do is put a 2 second delay on the key from a previous press (on the same key) for it to spit out the keystroke. Does anyone know anything that could do this? please

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic