DavidOConnor:
Here is some great info on debouncing...
Debouncing Contacts and Switches
And the pivotal statement from that:
The undebounced switch must connect to a programmed I/O pin, never to an interrupt.
fungus:
DavidOConnor:
mechanical encoders need debounce.No they don't. Quadrature encoding makes debouncing unnecessary, only one switch can be bouncing at any given time.
Not so sure about that - it has been pointed out to me that as many use wiping contacts, there can be noise on the contacts.