When Were Baby Monitors Invented

In 1937, Zenith Radio Nurse was the first product sold as a baby monitor. This Zenith Radio product was developed by Eugene F. McDonald and designed by Japanese-American sculptor and product designer Isamu Noguchi.

Infants and children have been heard over radios since 1937, with Eugene F. McDonald developing both a baby’s crib transmitter and a hospital receiver, which was invented by Zenith Radio Engineer Lester C. Van Vick. This Zenith product was called the “Zenith Radio Nurse”, and designed by Japanese-American sculptor and product designer Isamu Noguchi.

As a child, my parents cared for me in a separate one-room apartment New York City. My father did not want to unduly disturb my mother while she was sleeping, so he needed a way to hear me while he worked. He came up with the idea of using a radio placed by my crib that would allow him to listen to me breathe, and then left it up to one of his employees, Isamu Noguchi, to take that idea and develop the Zenith Radio Nurse into what we now call a baby monitor.

The first baby monitor was the Zenith Radio Nurse, introduced in 1937. Other early models were manufactured by Electro Medical Industries (Scovil) starting in 1940, and by mid-1943, RCA began producing a version that would become the best-selling product of its time.

Although the idea of a baby monitor today may seem like an obvious solution for parents, it was the first baby monitor and was developed to assist pediatricians with feeding babies over long-distance calls. The Zenith Radio Nurse was invented in 1937 when Dr. Peter Goldmark read of a mother who had to stop nursing her premature baby because she had tuberculosis and would spread the disease to her child. This gave birth to the concept of a radio,”receiver” that would pick up sound waves through a telephone line, and then transmit a signal over another line to a radio “speaker” located near the crib. The Zenith Radio Nurse was called such because it was operated by a nurse.

Baby monitors have been around over 80 years. A Zenith nurse call radio was used to notification mothers when baby needed something. Zenith did not make the monitor, Zenith sold the Zenith Radio Nurse under the trade name of “Radio Nurse”. The Radio Nurse was using a selenium photoelectric cell for transmission with a modulated tone on 38 kHz that was picked up by a local receiver (transmitter).

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Today the baby monitor has become a device in which parents are practically expected to own. You can find baby monitors on the list of just about every new parent’s must-haves.

The First Baby Monitor

Zenith Radio Nurse Baby Monitor Final
via State.com

The basic technology on which the first baby monitor was based grew out of the developments in radio technology which took place throughout the First World War. By the 1920’s, radio broadcasting had become a popular and widely distributed medium, and all of the pieces of the puzzle for making a baby monitor were publicly available.

Yet it took until 1937 before the first baby monitor would be commercially available. In 1932, the kidnapping of the Lindbergh baby (an incident widely reported in the American media,) inspired the president of a company called Zenith to experiment with a primitive baby monitor system in the hopes of keeping children safe from these types of incidents.

The First Commercial Version of a Baby Monitor

The president of Zenith, Eugene McDonald, first put together an improvised system of microphones, speakers, and radio equipment which allowed him to monitor the noise in his daughters room. After assuring himself that the concept worked, McDonald gave the task to the engineers at his company to develop a commercially viable version. With the help of Japanese designer Isamu Noguchi, the iconic look of the Radio Nurse was created and a simple, streamlined baby monitor system made its way to market.

In essence the Radio Nurse was more or less identical to modern baby monitors: the so-called “Guardian Ear” transmitter was plugged in somewhere in the child’s room, and the Radio Nurse receiver was plugged in near the parents.

Unfortunately for Zenith, the Radio Nurse suffered commercially and had issues with radio interference from other sources. It never took off, but it paved the way for the modern baby monitor.

The Rise of the Video Baby Monitor

Looking back to the first baby monitor, we can see that not much has changed for the basic audio baby monitor. LED sound indicators, talk-back features, and other neat bells and whistles have made them more versatile, but overall the basic principles are the same. Construction is certainly better, with clumsy vacuum tubes replaced by more reliable modern electronics.

Essential Reading: Top 10 – Best Baby Monitors of 2015

The major development in the modern baby monitor has come on two fronts: videos and computer integration. With the rise in capabilities of cameras, many parents are opting to have a complete audio visual picture over their child’s room. The burst in capabilities has given the market tons of cool toys like night vision, smart phone integration, powerful HD cameras, and much more.

The Latest and Greatest

See first hand where the evolution of the baby monitor has delivered us with a look at our Best Baby Monitors of 2015.

When Did Baby Monitors Become Popular?

Today the baby monitor has become a device which parents are practically expected to own. You can find baby monitors on the list of just about every new parents must-have’s.

There is good cause for all of this: having an ear (or even an eye) on what your child is doing when their alone can be an invaluable tool in preventing mishaps and even ensuring you never miss beautiful, private moments to be cherished for a lifetime.

Additional Reading: These 5 Images Make a Compelling Case for Owning a Baby Monitor

Yet this wasn’t always the case. Less than a hundred years ago, the concept of a baby monitor was utterly unheard of, and less than fifty years ago it was still a rarity. So what happened? Let’s take a look at a brief history of the baby monitor to get an idea of what changed.

There is good cause for all of this: having an ear (or even an eye) on what your child is doing when they are alone can be an invaluable tool in preventing mishaps and even ensuring you never miss beautiful, private moments to be cherished for a lifetime.

Yet this wasn’t always the case. Less than a hundred years ago, the concept of a baby monitor was utterly unheard of, and less than fifty years ago it was still a rarity. So what happened? Let’s take a look at a brief history of the baby monitor to get an idea of what changed.

Have you ever wondered how the baby monitor came to be? Who designed this remarkable life-saving device that can pass off as an assistant robotic parent? Because how else are modern-day parents expected to keep an eye on their little ones 24/7 given our demanding schedules!

There’s no need to speculate. If you want to learn all about the interesting history of baby monitors, as well as what the future holds for this innovative device, you’ve come to the right place.

Let’s Start At The Beginning: When, Where, How, And Why Were Baby Monitors Invented?

One thing is for certain: baby monitors were non-existent a century ago. Grandmothers can confirm this fact and gladly remind us how they raised us the old-fashioned way (without the help of technology or robotics). So, what changed? Who decided to invent a baby monitor, and why? Was it the brainchild of an anxious parent who was overwhelmed by constantly checking in on baby every five minutes? I’ll have you know that the motivation behind the unit’s invention was under the most somber circumstances.

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Baby monitors were first invented and released to the market in 1937. This was a revolutionary product that made parenting – for those who could afford it at least – a much less stressful endeavour. Unfortunately, the events that led to the need and subsequent invention of the first baby monitor were heartbreaking.

baby monitor app

It took a tragic kidnapping in 1932 for the first baby monitor to be invented. On this fateful Tuesday night, Charles Lindbergh’s son – aged 20 months at the time – was abducted from his home. A ransom note was found in his room confirming these suspicions. Charles was a prominent aviator in the United States of America. One would wonder how this could have possibly happened, given the fact that both the mother and nanny were at home on that particular day. Would this have happened if there was a baby monitor in the house? I’m inclined to think otherwise. Heartbreakingly, a month later the remains of Charles Jr were found just a few kilometres away from the Lindbergh residence. Seeing as the incident was a high profile case, it became national news and talk of the town. The story inspired Eugene McDonald, who was then President of a company called Zenith to design the first-ever baby monitor. The premise upon which this baby monitor was built upon was simple: to prevent a similar tragedy from happening to his child. Mr McDonald placed the unit in his daughter’s room in an attempt to monitor noises coming from the room. It was only after he felt satisfied with the unit’s performance did he give his company the go-ahead to commercialize the product.

The Zenith Radio Corporation engaged Isamu Noguchi to design the first baby monitor in 1937. The audio baby monitor which was complete and ready for sale by 1938 was named Zenith Radio Nurse. It had a sound amplifying system with two units, the Guardian Ear and a Radio Receiver. The guardian ear’s analog intercom system transmitted sound on a 300 kHz signal transmitter over the power line. The communication was one-way.

The Zenith radio nurse first sold for $29.95 in 1938, an equivalent of $523 in 2019. This was quite expensive, and in addition, it’s electrical transmission was plagued with technical problems, mainly distortions and RF interference. It shared a radio frequency with other consumer products, mainly the car radios and garage door openers. Below is how the Zenith radio nurse worked:

The Guardian Ear controlled a microphone, a sound amplifier, and an oscillator circuit(modulator ).
The generated circuit was conducted by means of the lighting circuit and was intercepted by the radio nurse.
The receiver unit of the Zenith Radio nurse had a detector, sound amplified and sound reproducer. The total amplification from the microphone to the speaker was in the order of 500,000 times. This was capable of making the slightest sound audible on the receiver.
The Zenith monitor did not work well with very loud volumes as it resulted in distortions and speaker rattles.

Following the Japanese attack of Pearl Harbor, the anti-Japanese sentiments swept through America, and many receivers were destroyed, making them very scarce. It is now sold as an antique and can be found in a few museums. If you are interested and want to learn more about the Zenith Radio Nurse, you can read the original Zenith Radio Manual.

Check out our range of safety baby monitors here.

The first designed baby monitor, Zenith Radio had one-way intercom and relied on an electrical circuit to transmit its analog audio signals.

Because of the challenges discussed above, Zenith Radio Nurse model was not produced after 1938, and museums bought the few zenith nurses because of its unique “industrial design”.

Between 1937 and 1960s, most baby monitors in the market were sold by a few manufacturers that used Zenith’s expired patent and analog signals to transmit audio. During WW II, troops used hand-held analog radio devices to communicate, and the biggest disadvantage was that only one conversation could occur at a time, on each channel. This is called the simplex mode.

The troops managed to overcome this obstacle by tuning receivers and frequencies to different frequencies, but this was difficult as they were using the lower frequency bands, 27 MHz or 49 MHz. The limited number of available frequencies limited them. Below is a video describing analog baby monitors in the 49 MHz bands.

Although analog radio devices were in use for a long period, they were mainly preferred because they had better ability to communicate especially when a received signal was weak and/or noisy.

The history of baby monitors is very much tied to the invention of a secure communication protocol called Frequency Hopping Spread Spectrum (FHSS). The protocol was invented in 1941 by two Americans, Hedy Lamarr and George Antheil who patented their invention of a secure security protocol that successfully enabled the Allied Forces to communicate and steer torpedoes without being noticed or intercepted.

The technology utilized a spread spectrum sequence which allowed signals to hop from one sub-frequency to another during transit. The spread spectrum technology was named Frequency Hoping Spread Spectrum (FHSS).

The FHSS guarantees 100% privacy of all communications, and the technology is now being used by some of the best-rated baby monitors such as Infant Optics, Babysense video baby monitor, Hellobaby, and Eufy Spaceview. We have a separate post with a list of top hack-proof baby monitors using FHSS technology which you can check out.

It is, however, important to note that while FHSS technology was discovered in the 1940s when the baby monitor industry was at its nascent stages, the technology was not used in baby monitors until the 90s. First, they had to discover digital signals to replace the analog baby monitors and enable encryption for better communication security.

Check out our post on What are the different types of baby monitors?

1974: A patent was filed in Spain by Fernandez Aguado Rafael. The patent was for an apparatus for monitoring intercom. It’s was described as a device to monitor young children and patients. Apart from monitoring audio, the baby monitor would allow two-way communication. This baby monitoring device would be different from the Zenith Radio Nurse in that it allowed the caregiver or the parent to communicate with the baby. It was however designed to be similar to a telephone as it had a call button and a switch and some argue that this was not entirely a baby monitor.

1979: A patent for a breath monitoring device was filed James K. Frost in Australia and later in the US.

The device was designed to monitor the breathing of an infant and sound an alarm in case of a cessation. An electromagnetic transducer was attached to a ‘cot’ or baby’s crib, and it was supposed to be compressed every time a child breathes.

The transducer was attached to a microphone, and it continuously produced noise if the breathing is normal. It did send an alarm in case the breathing ceased.

Prior to 2000s, most baby monitors did not use wifi to transmit signals. Analog baby monitors used the analog signal while digital baby monitors started using the 2.4 GHz Wifi, DECT or FHSS technologies to transmit audio and visual signals. It is worth mentioning here that some of the best baby monitors, the best-selling still use FHSS technology. Infant Optics DXR 8 and Eufy Spaceview are the two most secure baby monitors that still use the FHSS transmission technology.

Prior to 2000s, baby monitors with a camera unit had gained a foothold in the 90s. As discussed in this article above, news outlets, including TV, ran several stories of nannies that were mistreating babies when parents were away. These stories were made possible by nannycams which recorded a video of the baby when the parents were away. Parents had seen the need to purchase baby monitors. As prices continued to fall in the 2000s and with the emergence of wifi baby monitors, baby monitors continued to become very popular.

Because of the stories, scared parents bought the nanny cams, and by the end of 1999, video baby monitors were fairly known by a good portion of American parents. Another big development in the 2000s was the use of wifi to transmit signals. The internet has contributed immensely to the growth of the baby monitors. There are more than 30 patents relating to video baby monitors at present with most of them seeking to utilize the 2.4 GHz band that is used by wifi.

All these were filed within the last two decades, and there are several other pending video baby monitor patents. Some of these baby monitors have had immense success with consumers. Arlo baby became one of the best-selling wifi baby monitors last year (2018) with parents being satisfied mostly with the picture and video quality. Video baby monitors are now being integrated with some of the smart home devices such as Apple Homekit, Amazon Alexa Echo, and Google Home Hub. Google has approved a list of cameras that are compatible with Google Home Hub, and Arlo and Nest are some of the compatible baby monitors.

We have compiled a list of some of our favourite baby monitors below:

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