One thing to mention is if you have a pedestal fan on or near the cot, the vibration of that fools the monitor into thinking the baby is ok. Once we took out DD but forgot to switch of the monitor, about an hour later that thing went off...

Ours is about 2.5yrs old so they may of fixed that issue
We only bought ours a few months ago, and the instructions do mention about having a fan or anything vibrate-y nearby. I'm guessing it's because the sensor pad has to be super sensitive to pick up a tiny baby breathing through the mattress

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