Problem with PING sensor

Hi, I have been working on making an airsoft turret that when someone comes within a certain distance, it starts shooting. I am using the PING sensor for the distance sensing. now i got it all built, with the exception of a few sensors that i am waiting to buy, and i started to test it. It worked fine for the first few days, but then today when I tried it the PING sensor is reading 124in 317cm no matter how far the object is. I didn't change any thing about my circuit or program. Could someone please help me figure out what is wrong?

Oh, first of all i am using a RBBB not an actual Arduino board but that hasn't mattered in the past, and for the gun, i have a power supply powering it through a small relay controlled by the RBBB. I also have a rotating base for it and the servo for that is controlled by a SSC-32 servo controller.

try wiggling the metal can around the sensors. i dropped one of my ping sensors once and it was pretty flaky after that. wiggling would temporarily make it give normal readings.

Wow thanks, that worked! the weird thing though is that it was just sitting there the whole time. but like you said, it temporarily fixed it. do you know how to permanently fix it?