Parents buy millions of baby monitors each year in the U.S., but most transmit only sounds or video images of the baby - both useful, but only if a parent is listening or watching. University of Florida engineering researchers have built a prototype baby monitor that focuses on a baby's breathing. If the baby's chest stops moving, the crib-mounted monitor detects the problem and sends an alarm to a portable unit kept by the parents. The system works by using Doppler radar to remotely scan the in-and-out movement of the baby's chest due to respiration.

The small, book-sized device attaches to the crib like a standard monitor. A remote station with red, blue, green, and yellow lights variously indicates the status of the baby's vital signs, the battery life of the station, and confirms the station's wireless connection to the crib monitor. The station emits a loud alarm and flashes a red light when the monitor detects that the baby's breathing activity has fallen below a preset threshold, or that he or she has stopped breathing. The Doppler system could also be used in a search-and-rescue robot to determine the presence of living people in structures damaged by earthquakes or explosions.

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