Baby Monitors

A baby monitor is a device that enables parents or caregivers to remotely listen to the sounds made by an infant using a transmitter unit with a microphone placed near the baby, and a receiver unit with a speaker carried by the caregiver.

Some models offer two-way communication and music playback features. Baby monitors are commonly used to alert caregivers when the baby wakes up, but they do not prevent Sudden Infant Death Syndrome (SIDS) and may create a false sense of security. It is also normal for infants and young children to talk to themselves, which can be heard over the monitor.


The Zenith Radio Nurse, developed by Eugene F. McDonald in 1937, was the first baby monitor. Designed by Isamu Noguchi, a Japanese-American sculptor and product designer, this Zenith Radio product allowed parents to remotely listen to their baby’s sounds, paving the way for modern-day baby monitors.

Video baby monitors (baby cams)

In addition to audio, many baby monitors now include a video camera, also known as a baby cam. Some models can be connected to a TV or include a portable LCD screen, while others allow parents to view their baby through a smartphone or computer.

Most video baby monitors have a night vision feature with infrared LEDs for visibility in low light conditions. Some monitors even include features like night lights, built-in lullabies, and temperature and movement monitoring devices. However, not all monitors have these additional features.

Movement monitors

Sensor pads placed under the crib mattress of a baby movement monitor detect movement and sound an alarm if there is no movement for 20 seconds.

Wired and wireless

Baby monitors can operate wirelessly or with wires, and some can use household wiring such as X10. Wireless systems use radio frequencies that may be affected by interference from other devices. Digital audio wireless systems like DECT are more resistant to interference and can transmit up to 300 meters.

Analog audio transmissions can pose a privacy risk if intercepted. Some monitors support multiple cameras on one handheld monitor, and FM transmitters paired with a microphone can be a cost-effective DIY solution.

Smartphone as baby monitors

Smartphone apps can be used to monitor a camera-equipped device remotely or via Wi-Fi/Bluetooth, eliminating the need for a dedicated device in the baby’s room.