There are two basic types: audio and video/audio. Some are analog, others are digital. All monitors operate within a selected radio frequency band to send sound from a baby's room to a receiver in another room. Each monitor consists of a transmitter (the child/nursery unit) and one or more receivers. Prices range from about $25 to $150 for audio monitors and about $80 to $300 for audio/video monitors.
Baby monitors shouldn't be used as a substitute for adult supervision. They should be considered as an extra set of ears—and, in some cases, eyes—that help parents and caregivers keep tabs on sleeping babies. Using one can alert you to a situation before it becomes serious, for example, if your baby is coughing, crying, or making some other sign of distress. Experts warn that you can't rely on a monitor to prevent Sudden Infant Death Syndrome (SIDS).
No ordinary monitor, the Cocoon Cam lets you see your baby and a graph that shows breathing patterns on your smartphone. The camera watches the rise and fall of your child’s chest and sends an instant notification if something seems off. You’ll also get alerts when your child has fallen asleep, is crying or is about to wake up. Since the Cocoon Cam live streams the video and audio over WiFi, you can watch your baby from anywhere.
With a dedicated baby monitor, push-to-talk capabilities will usually be integrated, as well as the ability to record and share still images and video clips (even if some monitors require a subscription to do so). Baby video monitors will also usually have built-in music files that you can play to soothe your child. Just the ability to pan and tilt the camera — the Nest has a fixed 130-degree wide-angle perspective — means you can follow your kids wherever they scamper.