I had that same problem with 2 of the 4 that ive had. Both of them, just didnt seem to take as many pics as my other cam, and like you said i literally had to jump up and down waving my arms to set it off. Then one other Stealth Cam wouldnt rewind film,, and another just took pictures of nothing,, two rolls of film without a single animal on them,, needless to say it was my last Stealth.