Help with simple pedometer circuit

[ilfunx]

Hey im doing a small project, and I am using a piezoelectric sensor to get my pulse input. The problem is that i get multiple pulses and hence my counter skips counts by 2-3 steps. I was asked to make a debouncing circuit but i have no idea what it is. Please give me any links, schematics or anything to help me out. I have attached my circuit diagram
Thanks

 

[(*steve*)]

How fast can these pulses legitimately come?

Add a monostable after U5 to ignore pulses that are too close together