So, if you can add that chip [7414] then you can safely forget about de-boucnce.

Sorry Sriharsha, I do not agree! Contact bouncing cannot generally solved by only inserting a Schmitt-trigger!! May be you used a switch with good contacts, may be contacts were new, so that bouncing was minimum?

Some years ago I analyzed performance of many different switches, with differently aged contacts, and found, that for new contacts bouncing can take place in the range of about 1...20msec, with many togglings from rail to rail for each make. If contacts are older or made of poor contact material, much longer bouncing periods can be observed, and, very frustating, even bounces, when switch was pressed 'long' time ago and was kept pressing...

My resume from these tests was:

1. to choose a debouncing time of 50msec,
2. to use good contacts (best gold) and
3. to limit switch current!

For very secure switching not only overcurrents must be avoided, but also to small currents. I have obtained very good results with switching current of about 500µA. No more than 1mA and no less than 100µA, as a rule of thumb. It depends on switch, of course.

Regards,
Kai