Baby monitor
Encyclopedia
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
system used to remotely listen to sounds made by an infant
Infant
A newborn or baby is the very young offspring of a human or other mammal. A newborn is an infant who is within hours, days, or up to a few weeks from birth. In medical contexts, newborn or neonate refers to an infant in the first 28 days after birth...
. The transmitter unit, equipped with a microphone
Microphone
A microphone is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. In 1877, Emile Berliner invented the first microphone used as a telephone voice transmitter...
, is placed near to the child. It transmits the sounds the baby makes by radio wave
Radio Wave
Radio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...
s to a receiver unit with a speaker
Loudspeaker
A loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...
carried by, or near to, the person caring for the infant. Some baby monitors provide two-way communication
Two-way communication
Two-way communication - uses communication to negotiate with the public, resolve conflict, and promote mutual understanding and respect between the organization and its public. Two-Way Communication in Public Relations...
which allows the caregiver to speak back to the baby (parent talk-back). Some allow music to be played to the child.
One of the primary uses of baby monitors allows attendants to hear when an infant wakes, while out of immediate hearing distance of the infant. Although commonly used, there is no evidence that these monitors prevent SIDS
Sudden infant death syndrome
Sudden infant death syndrome is marked by the sudden death of an infant that is unexpected by medical history, and remains unexplained after a thorough forensic autopsy and a detailed death scene investigation. An infant is at the highest risk for SIDS during sleep, which is why it is sometimes...
, and many doctors believe they provide a false sense of security. Infants and young children can often be heard over a baby monitor in crib talk
Crib talk
Crib talk or crib speech is pre-sleep monologue made by young children while in bed. This starts somewhere around one-and-a-half years and usually ends by about two-and-a-half years of age, though children can continue longer. It consists of conversational discourse with turn-taking often...
, in which they talk to themselves. This is a normal part of practicing their language skills.
Video baby monitors (baby cams)
Some baby monitors also use a video cameraVideo camera
A video camera is a camera used for electronic motion picture acquisition, initially developed by the television industry but now common in other applications as well. The earliest video cameras were those of John Logie Baird, based on the electromechanical Nipkow disk and used by the BBC in...
to show pictures on the receiver, either by plugging the receiver into a television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
or by including a portable LCD screen. This type of surveillance camera is often called a baby cam.
Some baby cams can work at night with low light levels. Most video baby monitors today have a night vision
Night vision
Night vision is the ability to see in low light conditions. Whether by biological or technological means, night vision is made possible by a combination of two approaches: sufficient spectral range, and sufficient intensity range...
feature. Infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
LEDs
Light-emitting diode
A light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting...
attached on the front of the camera allow a user to see the baby in a dark room. Video baby monitors that have night vision mode will switch to this mode automatically in the dark.
Baby monitors continue to evolve and now also can utilize features such as night lights and built-in lullabies. These are not available in all monitors.
Wired and wireless
Baby monitor generally use wireless systems, but can also use wires or may operate over existing household wiringPower line communication
Power line communication or power line carrier , also known as power line digital subscriber line , mains communication, power line telecom , power line networking , or broadband over power lines are systems for carrying data on a conductor also used for electric power transmission.A wide range...
such as X10
X10 (industry standard)
X10 is an international and open industry standard for communication among electronic devices used for home automation, also known as domotics. It primarily uses power line wiring for signaling and control, where the signals involve brief radio frequency bursts representing digital information...
.
Wireless systems use radio frequencies
Radio spectrum
Radio spectrum refers to the part of the electromagnetic spectrum corresponding to radio frequencies – that is, frequencies lower than around 300 GHz ....
that are designated by governments for unlicensed use. For example, in North America frequencies near 49 MHz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
, 902 MHz or 2.4 GHz are available. While these frequencies are not assigned to powerful television or radio broadcasting transmitters, interference
Electromagnetic interference
Electromagnetic interference is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source. The disturbance may interrupt, obstruct, or otherwise degrade or limit the effective performance of the circuit...
from other wireless devices such as cordless telephone
Cordless telephone
A cordless telephone or portable telephone is a telephone with a wireless handset that communicates via radio waves with a base station connected to a fixed telephone line, usually within a limited range of its base station...
s, wireless toys
Radio control
Radio control is the use of radio signals to remotely control a device. The term is used frequently to refer to the control of model vehicles from a hand-held radio transmitter...
, computer wireless networks
Wireless LAN
A wireless local area network links two or more devices using some wireless distribution method , and usually providing a connection through an access point to the wider internet. This gives users the mobility to move around within a local coverage area and still be connected to the network...
, RADAR
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
, Smart Power Meters
Smart meter
A smart meter is usually an electrical meter that records consumption of electric energy in intervals of an hour or less and communicates that information at least daily back to the utility for monitoring and billing purposes. Smart meters enable two-way communication between the meter and the...
and microwave oven
Microwave oven
A microwave oven is a kitchen appliance that heats food by dielectric heating, using microwave radiation to heat polarized molecules within the food...
s is possible.
Digital audio wireless systems using DECT
Digital Enhanced Cordless Telecommunications
Digital Enhanced Cordless Telecommunications , usually known by the acronym DECT, is a digital communication standard, which is primarily used for creating cordless phone systems...
, are resistant to interference and have a range up to 300 m.
Analog audio transmissions can be picked up at a distance from the home by a scanner receiver
Scanner (radio)
A scanner is a radio receiver that can automatically tune, or scan, two or more discrete frequencies, stopping when it finds a signal on one of them and then continuing to scan other frequencies when the initial transmission ceases....
or other baby monitor receivers, and so present a risk to privacy as long as the transmitter is switched on. Digital transmission such as Frequency-hopping spread spectrum
Frequency-hopping spread spectrum
Frequency-hopping spread spectrum is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver...
provides a level of protection from casual interception.
Some wireless baby monitors support multiple cameras on one handheld monitor-receiver. These systems are even compatible with a standard wireless security camera
Wireless security camera
Wireless security cameras are closed-circuit television cameras that transmit a video and audio signal to a wireless receiver through a radio band. Many wireless security cameras require at least one cable or wire for power; "wireless" refers to the transmission of video/audio...
.
Smartphone as baby monitors
Software for smartphones is another style of baby monitor. When the software detects a sound, it calls a telephone number and allows the user to hear the sound made by the child. This eliminates the dedicated transmitter system, and can reach as far as the public telephone network.Other features
Portable battery-operated receivers can be carried by the caregiver around the house. The transmitter stays near the infant crib and is usually plugged into a socketDomestic AC power plugs and sockets
AC power plugs and sockets are devices for removably connecting electrically operated devices to the power supply. Electrical plugs and sockets differ by country in rating, shape, size and type of connectors...
. Some baby monitor packages include two receivers.
Baby monitors may have a visible signal as well as repeating the sound. This is often in the form of a set of lights to indicate the noise level, allowing the device to be used when it is inappropriate or impractical for the receiver to play the sound. Other monitors have a vibrating alert
Vibrating alert
A vibrating alert is a feature of communications devices to notify the user of an incoming connection. It is particularly common on mobile phones and pagers and usually supplements the ring tone....
on the receiver making it particularly useful for people with hearing difficulties.
Systems with several transmitters can monitor several rooms in the home at once.
Transmitters with movement sensors such as a pressure-sensitive mat placed beneath the child's mattress give additional warning of restless activity by the infant.
Temperature sensors are a feature on new baby monitors.
Snapshot recording to microSD cards is a brand new feature found in some baby monitors.
See also
- Frequency-hopping spread spectrumFrequency-hopping spread spectrumFrequency-hopping spread spectrum is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver...
(FHSS) - Nanny camNanny camA Nanny Cam, or Nanny Camera, sensationalized to the phrase "spy camera" is a hidden video camera that has been secretly installed within a common household object...
- Spy video carSpy video carThe Spy Video Car is a hybrid product created by mixing a traditional RC car and a video baby monitor. The remote controller communicates digital command via the 49 MHz frequency to the car for control, and the camera on the car transmits video via the 2.4 GHz frequency to the remote...
- Sudden infant death syndromeSudden infant death syndromeSudden infant death syndrome is marked by the sudden death of an infant that is unexpected by medical history, and remains unexplained after a thorough forensic autopsy and a detailed death scene investigation. An infant is at the highest risk for SIDS during sleep, which is why it is sometimes...
(SIDS) - Title 47 CFR Part 15