Just sharing some advice based on the experience of raising 3 children who are now all adults. Our last, who is now 25, was a premie with a birth weight of just under 4-lbs. During her first year she slept on a matress equipped with a breathing monitor which would sound a loud alarm on any abrupt change in breathing patterns. Of course during that year, at least one of us was never more than 25 -feet away from the crib at any time on a 24/7 basis.
With the other two children, we simply took the usual precautions.
-- Until age 2, their crib shared our bedroom
-- During waking or nap hours, they were never out of our eyesight
-- We avoided the tendency to put stuffed animals or toys inside of their cribs
-- Hourly crib checks are an essential safety precaution
-- Generally, we followed the same practices as used in the hospital maternity ward
In closing, I am assuming very little about you, but if you are concerned about the possibility of SIDS while you are sleeping, and I assume that you are sleeping in the same room with your infant, a loud audible breathing alarm would be a far more practical solution than any sort of wireless device that may or may not function when needed most Check with the maternity ward of any major hospital and see what they use.
Harry C.