...I can try to help
First off, when you switch the Snuza on and it makes it's blip-blip "on" noise, look at the little lights. The battery light should flash green. I went through a period where the alarm was going off a lot because the diaper was bagging out a bit. You can think that you have it on there securely but, depending on baby's position, the sensor can still disconnect ever-so-slightly from his skin causing the alarm to go off. So assuming that's the issue, here's what I do: I make sure the diaper is folded over the way they say to do it, and I secure it tightly with the Velcro tabs. After slipping the Snuza into place, I put a onesie on that's kind of snug, helping to keep the sensor touching the skin at all times. And, finally, I put on a pair of pajama bottoms and make sure the elastic waist is over the Snuza as an extra way to keep it in place and connecting to the skin. I haven't had any problems since doing that. I hope this helps!! I think this is the battery but you can also call the customer service number on their website to be sure:
http://www.amazon.com/gp/aw/d/B0046JVTS8/ref=s9_simh_awgw_d0_g147_i5/191-3275248-8203146?aid=aw_gw&apid=1353730462&arc=1201&arid=0JQJW1RF6J87XR6W7RYQ&asn=center-6&pf_rd_i=GatewayAW&pf_rd_m=ATVPDKIKX0DER&pf_rd_p=1353730462&pf_rd_r=0JQJW1RF6J87XR6W7RYQ&pf_rd_s=center-6&pf_rd_t=7201
