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A baby monitor, also known as a baby alarm, is a radio system used to remotely listen to sounds made by an infant. An audio monitor consists of a transmitter unit, equipped with a microphone, placed near to the child. It transmits the sounds by radio waves to a receiver unit with a speaker carried by, or near to, the person caring for the infant. Some baby monitors provide two-way communication which allows the parent to speak back to the baby (parent talk-back). Some allow music to be played to the child. A monitor with a video camera and receiver is often called a baby cam.
One of the primary uses of baby monitors is to allow 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, and many doctors believe they provide a false sense of security. [1] Infants and young children can often be heard over a baby monitor in crib talk, in which they talk to themselves. This is a normal part of practising their language skills.
The first baby monitor was the Zenith Radio Nurse in 1937. This Zenith Radio product was developed by Eugene F. McDonald, and designed by Japanese-American sculptor and product designer Isamu Noguchi. [2]
Some baby monitors also use a video camera to show pictures on the receiver, either by plugging the receiver into a television 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 feature. Infrared LEDs 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. Some advanced baby cams now work over Wi-Fi so parents can watch babies through their smartphone or computer.
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. Some include temperature and movement monitoring devices to sit underneath a mattress or close to the baby within a cot.
A baby movement monitor uses sensor pads placed under the crib mattress to detect movement, if movement stops for more than 20 seconds an alarm will sound.
Baby monitors generally use wireless systems, but can also use wires or may operate over existing household wiring such as X10.
Wireless systems use radio frequencies that are designated by governments for unlicensed use. For example, in North America frequencies near 49 MHz, 902 MHz or 2.4 GHz are available. While these frequencies are not assigned to powerful television or radio broadcasting transmitters, interference from other wireless devices such as cordless telephones, wireless toys, computer wireless networks, radar, Smart Power Meters and microwave ovens is possible.
Digital audio wireless systems using DECT, are resistant to interference and have a range up to 300 m. [3]
Analog audio transmissions can be picked up at a distance from the home by a scanner receiver 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 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.
FM transmitters, paired with a microphone can be an inexpensive solution to a DIY baby monitor, since clock radios can also be used as one.
Smartphone apps allow a user to monitor a camera-equipped device, such as another smartphone or a tablet. Alternatively, Wi-Fi or Bluetooth can link a camera to a dedicated app on a smartphone or tablet. This means a smart device doesn't need to be left in the baby's room.
Portable battery-operated receivers can be carried by the parent around the house. The transmitter stays near the infant crib and is usually plugged into a AC socket. 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 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.
The new voluntary ASTM International F2951 standard has been developed to address incidents associated with strangulations that can result from infant entanglement in the cords of baby monitors. This standard for baby monitors includes requirements for audio, video, and motion sensor monitors. It provides requirements for labeling, instructional material and packaging and is intended to minimize injuries to children resulting from normal use and reasonably foreseeable misuse or abuse of baby monitors.
Signals of baby monitors can be received by third parties, presenting privacy issues. [4]
A communications system or communication system is a collection of individual telecommunications networks, transmission systems, relay stations, tributary stations, and terminal equipment usually capable of interconnection and interoperation to form an integrated whole. The components of a communications system serve a common purpose, are technically compatible, use common procedures, respond to controls, and operate in union.
In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves.
In electronics, a remote control is an electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operate devices such as a television set, DVD player or other home appliance. A remote control can allow operation of devices that are out of convenient reach for direct operation of controls. They function best when used from a short distance. This is primarily a convenience feature for the user. In some cases, remote controls allow a person to operate a device that they otherwise would not be able to reach, as when a garage door opener is triggered from outside.
Wireless communication is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most common wireless technologies use radio waves. With radio waves, intended distances can be short, such as a few meters for Bluetooth or as far as millions of kilometers for deep-space radio communications. It encompasses various types of fixed, mobile, and portable applications, including two-way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of applications of radio wireless technology include GPS units, garage door openers, wireless computer mouse, keyboards and headsets, headphones, radio receivers, satellite television, broadcast television and cordless telephones. Somewhat less common methods of achieving wireless communications involve other electromagnetic phenomena, such as light and magnetic or electric fields, or the use of sound.
A hidden camera or spy camera is a still or video camera used to record people without their knowledge. The term “hidden camera” is commonly used in TV shows, sometimes when subjects are unaware that they are being recorded, and usually lacking their knowledge and consent. The term “spy camera” is generally used when the subject would object to being recorded if they were aware of the camera's existence. In contrast, "security cameras" refer to cameras that are visible and/or accompanied by a warning notice of their presence.
Automatic vehicle location is a means for automatically determining and transmitting the geographic location of a vehicle. This vehicle location data, from one or more vehicles, may then be collected by a vehicle tracking system to manage an overview of vehicle travel. As of 2017, GPS technology has reached the point of having the transmitting device be smaller than the size of a human thumb, able to run 6 months or more between battery charges, easy to communicate with smartphones — all for less than $20 USD.
A walkie-talkie, more formally known as a handheld transceiver (HT), is a hand-held, portable, two-way radio transceiver. Its development during the Second World War has been variously credited to Donald Hings, radio engineer Alfred J. Gross, Henryk Magnuski and engineering teams at Motorola. First used for infantry, similar designs were created for field artillery and tank units, and after the war, walkie-talkies spread to public safety and eventually commercial and jobsite work.
In radio communications, a radio receiver, also known as a receiver, a wireless, or simply a radio, is an electronic device that receives radio waves and converts the information carried by them to a usable form. It is used with an antenna. The antenna intercepts radio waves and converts them to tiny alternating currents which are applied to the receiver, and the receiver extracts the desired information. The receiver uses electronic filters to separate the desired radio frequency signal from all the other signals picked up by the antenna, an electronic amplifier to increase the power of the signal for further processing, and finally recovers the desired information through demodulation.
A doorbell is a signaling device typically placed near a door to a building's entrance. When a visitor presses a button, the bell rings inside the building, alerting the occupant to the presence of the visitor. Although the first doorbells were mechanical, activated by pulling a cord connected to a bell, modern doorbells are electric, operated by a pushbutton switch. Modern doorbells often incorporate intercoms and miniature video cameras to increase security.
A security alarm is a system designed to detect intrusion, such as unauthorized entry, into a building or other areas such as a home or school. Security alarms used in residential, commercial, industrial, and military properties protect against burglary (theft) or property damage, as well as personal protection against intruders. Security alerts in neighborhoods show a connection with diminished robbery. Car alarms likewise help protect vehicles and their contents. Prisons also use security systems for the control of inmates.
FM broadcasting is a method of radio broadcasting using frequency modulation (FM). Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high fidelity sound over broadcast radio. FM broadcasting is capable of higher fidelity—that is, more accurate reproduction of the original program sound—than other broadcasting technologies, such as AM broadcasting. It is also less susceptible to common forms of interference, reducing static and popping sounds often heard on AM. Therefore, FM is used for most broadcasts of music or general audio. FM radio stations use the very high frequency range of radio frequencies.
A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow for simultaneous communication in both directions between two connected parties or to provide a reverse path for the monitoring and remote adjustment of equipment in the field. There are two types of duplex communication systems: full-duplex (FDX) and half-duplex (HDX).
A motion detector is an electrical device that utilizes a sensor to detect nearby motion. Such a device is often integrated as a component of a system that automatically performs a task or alerts a user of motion in an area. They form a vital component of security, automated lighting control, home control, energy efficiency, and other useful systems.
A wireless microphone, or cordless microphone, is a microphone without a physical cable connecting it directly to the sound recording or amplifying equipment with which it is associated. Also known as a radio microphone, it has a small, battery-powered radio transmitter in the microphone body, which transmits the audio signal from the microphone by radio waves to a nearby receiver unit, which recovers the audio. The other audio equipment is connected to the receiver unit by cable. In one type the transmitter is contained within the handheld microphone body. In another type the transmitter is contained within a separate unit called a "bodypack", usually clipped to the user's belt or concealed under their clothes. The bodypack is connected by wire to a "lavalier microphone" or "lav", a headset or earset microphone, or another wired microphone. Most bodypack designs also support a wired instrument connection. Wireless microphones are widely used in the entertainment industry, television broadcasting, and public speaking to allow public speakers, interviewers, performers, and entertainers to move about freely while using a microphone without requiring a cable attached to the microphone.
ANT is a proprietary multicast wireless sensor network technology designed and marketed by ANT Wireless. It provides personal area networks (PANs), primarily for activity trackers. ANT was introduced by Dynastream Innovations in 2003, followed by the low-power standard ANT+ in 2004, before Dynastream was bought by Garmin in 2006.
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by another antenna connected to a radio receiver. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing, and other applications.
Wireless speakers are loudspeakers that receive audio signals using radio frequency (RF) waves rather than over audio cables. The two most popular RF frequencies that support audio transmission to wireless loudspeakers include a variation of WiFi IEEE 802.11, while others depend on Bluetooth to transmit audio data to the receiving speaker.
There are several uses of the 2.4 GHz band. Interference may occur between devices operating at 5GHz. This article details the different users of the 2.4 GHz band, how they cause interference to other users and how they are prone to interference from other users.
Wireless security cameras are closed-circuit television (CCTV) 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. However, some wireless security cameras are battery-powered, making the cameras truly wireless from top to bottom.
An RF module is a (usually) small electronic device used to transmit and/or receive radio signals between two devices. In an embedded system it is often desirable to communicate with another device wirelessly. This wireless communication may be accomplished through optical communication or through radio-frequency (RF) communication. For many applications, the medium of choice is RF since it does not require line of sight. RF communications incorporate a transmitter and a receiver. They are of various types and ranges. Some can transmit up to 500 feet. RF modules are typically fabricated using RF CMOS technology.