got the ping sensor wired up. it works totally great for the most part, except, it keeps going wild erratic. like, something will be moving in front of it, and all of a sudden, it swings to the top of it's range for a portion of a second, and then back. i've tried it with multiple ping sensors, using the ping example code, and i'm sure it's wired correctly. is this a known issue with the pings? is there some code trick i can do to smooth the input?