I have attached 2 circuits. The first one is basic de-bounce:
R1 is the pull-up resistor. R2 is to reduce the discharge current out of the capacitor to ground when a switch is closed. The exact values don't matter too much, but typically R1 of 10k and R2 of 1k to 10k work well.
C1 can be 0.1u to 1u. The larger number will give a longer time constant.
The second circuit has all the bells and whistles, including a Schmitt trigger IC (cheap) for sharpening up the output transitions.
Encoder Debounce 01.pdf (54.6 KB)
Encoder Debounce 02.pdf (105.2 KB)
If you have any questions about how to find the parts, let me know.
This video goes into some scope work:
