I am an avid fan of television detective shows. Not the rough and tumble shows where someone is always hitting someone or shooting at someone. But rather, if you will excuse the expression, the more “intellectual” ones where most of the action takes place in a sophisticated crime lab and most of the action consists of people looking through a microscope or checking the readout from a mass spectrometer. However, even in the second, and to me higher-level category, at some point, you are almost bound to see members of the constabulary banging on the front door of a house and shouting, “Police! Open up!” Then instantaneously smash through the door, guns drawn and ready for action.
To a certain degree, I can understand this. When you expect that whoever is on the other side of the door is a desperate criminal who may also have their gun drawn, you want to minimize their chances of their using it before you render them immobile. The puzzling thing is, it seems that more often than not even when they arrive at a house simply looking for information, they also bang on the door rather than ringing the doorbell.
While researching this essay, I came across a number of explanations for this. We will further examine some of the answers to this conundrum. But first, let’s return to the topic as a whole—the doorbell.
The doorbell has a long and colorful history, dating back many centuries. At one time rare, today in so-called First World countries, a house or apartment without a doorbell would be rare indeed. By contrast, in the so-called Third World countries, where most of the population lives in small villages rather than towns and cities, doorbells are largely unknown for the very good reason that there is no real use for them.
Although perhaps not quite as ordinary as many of the other objects that have been discussed in this series, the doorbell has nevertheless played a key role in shaping the modern world. And therefore justly deserves to be included on the list of what I like to call “extraordinary ordinary things.“
A Short History of the Doorbell
Actually, “short” is misleading. The doorbell has a very long history if you include its direct predecessor, the doorknocker.
Announcing oneself at someone’s dwelling by knocking on the door with one’s knuckles is an age-old custom. Using a mechanical device attached to the door to make a sound is much more recent, dating back only to the Middle Ages. However, because these first-generation doorknockers produced a rather rough, jarring sound, they were subsequently replaced by something less annoying—bells. Yes, actually bells; hence, the name “doorbell.”
Doorknockers and doorbells introduced during the Middle Ages proved to be extremely useful for small buildings; however, they fell short for larger buildings in which no one might be close enough to the door to hear the sound. One ingenious solution to this problem dates back to 1st century Alexandria (ancient Egypt)—temples equipped with hydraulic doorbells. In one configuration, a large container of water was attached to a trumpet. When someone opened the door to the temple, pulleys caused the trumpet to tip over. The water then forced air through the instrument, causing it to blast out a sound to announce to the priests throughout the building that they had a visitor.
The electric doorbell, the device we tend to think of today, made its appearance quite recently in human history. It was invented by American Joseph Henry in 1831. Henry, the first Secretary of the prestigious Smithsonian Institution (Washington, D.C.), was a reputed scientist who did groundbreaking work in electricity and magnetism. As a lasting honor, his name was chosen as the SI unit for electric inductance, i.e. the “henry” (plural “henries”).
Although quite a technological leap, it took many, many years, indeed almost a century, of development to resolve problems that impeded Henry’s pioneering invention from being taken up by the general public. For example, the first doorbells produced an annoying “bzzz” sound. This was later replaced by a more melodic “ding dong” sound, which is still indicative of doorbells today.
With major technical and consumer problems solved, in the 1920s the popularity of doorbells in the United States skyrocketed. Their popularity got a second flip in the 1930s with the introduction of chimes, i.e. the ability to play somewhat complex tunes rather than simply a bzzz or a ding dong.
Aside from chimes being more melodic, part of their attraction was the idea that door chimes were a sign of class and upward mobility. So much so that a specific niche was often built into new homes specifically to give the status-identifying door chime a conspicuous place of honor at the front door.
Types of Doorbells
In our techno-consumer age, it should not be surprising that doorbells today come in all kinds of shapes, sizes, designs, and other features to fit the needs (and sometimes the aesthetics) of just about every kind of buyer and user. To make sense of them all (and not all of them are bells), “visitor-announcing systems” can be divided into the following categories.
Natural systems. This is not an official category. It is simply a reminder that before inventors and entrepreneurs got interested in them, perhaps the best way to announce one’s presence was by rapping one’s knuckles on the door to alert the occupants that someone was outside seeking entrance. However, this was not the only system.
For a couple of years in the mid-1960s, I lived in Tanzania. At that time, the houses in small villages generally didn’t have a door per se. Rather, villagers hung cloth over the entrance, so there really was nothing to rap one’s knuckles on. Moreover, the dwellings were small, there was little chance that the presence of someone outside seeking entrance would have hardly gone unnoticed. So instead of knocking, the visitor would call out “Hodi” to signal their presence, and the occupant could reply “Karibu” meaning please come in. I imagine a similar practice existed (and still exists) in many other places around the world where houses don’t really have a front door.
Where houses do have front doors, the age-old practice of knocking still serves very well—provided that the house is small such that the occupant will always be fairly close to the door. This is probably still the case in more places around the world than one might imagine. However, for larger edifices (houses, shops, business offices, etc.), the people inside may not hear the knock. This is where specifically designed and installed “visitor-announcement systems” come in.
The simplest pre-electric example of a”visitor-announcement system” was the door knocker, in use since ancient times. This device, mounted on the door, made a sound when the visitor banged the hinged knocker onto the metal plate installed under it. Upscale door knockers also served as decoration at the entrance to the house. Simple or decorative, they worked better than simply knocking on the door with one’s knuckles being slightly louder.
To better alert people inside the house to the presence of a visitor, in the 18th-century mechanical chimes were invented to expand the range of sounds. These consisted of one or more bells installed inside the home that were manually activated when a visitor pulled a chain or string to set them ringing. These doorbells were essentially the same design as the “servants’ bells” often seen in period films set in the late1800s. In this setup, a bell would ring in the servants’ quarters when someone far away in the house pulled a chain to summon them.
Another early mechanical device used a twist handle. When the visitor at the door turned the handle, it caused a tiny hammer or clapper to strike a bell on the other side of the door, producing a rapid trill or ringing sound. Even today, retail stores wanting to create a “ye olde shoppe” atmosphere for customers often use door-mounted mechanical bells that ring each time anyone enters or leaves the establishment.
Electrical systems. As noted earlier, the electric doorbell was invented in 1831 by polymath scientist Joseph Henry, better known for his groundbreaking work on the fundamental nature of electricity and magnetism.
Henry’s doorbell was powered by batteries, which at the time were expensive and required periodic replacement. When household electricity started becoming common in the early 1900s, these were replaced by transformers, allowing the use of a household current.
During the first two decades of the 20th century, most electric doorbells were loud, somewhat annoying buzzers. Musical bells and chimes (musically tuned groups of bells) with significantly more pleasing tones became popular in the 1930s. The Depression and the Second World War quickened doorbell development, which once again surged in popularity during the 1950s. In the mid-1960s, decorative and multifunctional door chimes became more popular. They were built with clocks atop the chimes and decorative plaques hiding indoor components.
Electric doorbells can be divided into two major subcategories: wired and wireless.
- Wired doorbells. As previously noted, doorbells began becoming generalized in the early 1900s as more and more homes and business establishments became electrified. Wired electric doorbell components generally include an outdoor button, wiring, a transformer, and a bell or chimes. The bell or chime functions when the outside button is pushed, causing an electrical current to flow into the transformer. The transformer takes the line voltage down from 120 V to around 12 V and powers the chime and doorbell button at the lower voltage.
- Wireless doorbells. Wireless doorbells are, as the name describes, doorbells that operate without wire connections. However, this simple definition is inadequate because eliminating wires allows these doorbells to be easily connected to computers. This new capability in a very real sense represents the start of a new era in doorbell evolution. We will explore this change in more detail later.
Why Don’t Police Officers Ring Doorbells?
Back to the vexed question: Why do police officers on the radio, in films, and on TV often loudly bang on a front door rather than ringing the bell; even when they arrive at a house simply to gather or deliver information?
Here are three principles that seem to govern the practice in real life and have been adopted by the entertainment media as justification for their depictions.
- Efficiency. The police want to be certain that the occupant of the house or apartment is aware of their presence. “A doorbell for some reason could be disconnected; your knuckles never are.”
- Legality. It ensures that the occupant cannot plausibly claim ignorance of the police presence. “It is not so easy to deny that you couldn’t hear someone rapping on your door with the butt end of a flashlight.”
- Modulation. A knock can be adjusted to have a particular desired effect, e.g. subtitle or forceful. If you simply want to talk with the occupant, a calm but loud knock is called for. If you want to signal to the occupant that, if necessary, you are prepared for action, a loud, forceful knock is called for. “There is a great difference between knock, knock, knock and gently saying ‘police,’ and Knock, Knock, Knock, and shouting ‘Police, open up!”
Knock, Knock Jokes
It may seem somewhat incongruous that so-called “knock-knock jokes” began becoming embedded in American humor in the early 20th century, just about the time doorknockers were rapidly disappearing in favor of electric doorbells. Perhaps they arose as a touch of nostalgia at the passing of an ages-old way of doing things. Or perhaps not, because new knock-knock jokes are still being invented all the time, a century after the transition began taking place.
While knock-knock jokes may seem to be typically American, some scholars consider the prototype for the joke can be attributed to William Shakespeare (1554–1616), and specifically Macbeth, Act 2, Scene 3. Knock-knock jokes also exist in other languages; however, the sound “knock, knock” is replaced by the language’s equivalent. In Italian, French, and Spanish, it is “toc-toc”; in Dutch it is “klopklop”; in German “KlopkKlopK”; in Hungarian “tuk tuk”; in Hebrew “tuk tuk”, etc.
All knock-knock jokes follow a set pattern consisting of five parts. For example:
Knock, knock. Who's there? Hal. Hal who? Hal will you know if you don’t open the door?
Knock, knock. Who's there? Orange. Orange who? Orange you going to let me in?
Knock. Knock. Who's there? Who. Who who? I didn't know you were an owl!
Knock, knock. Who’s there? Boo! Boo who? Here’s a tissue
As you might have guessed from these excruciatingly naive plays on words, knock-knock jokes are particularly favored by children, especially young children. However, a few knock-knock jokes (very few) offer something for sophisticated adults, especially those who still know how to tap into their inner child. Here are a few of my favorites.
Knock, knock Who’s there? Luke. Luke who? Luke through the peephole and find out.
Knock, knock. Who’s there? A little old lady. A little old lady who? I had no idea you could yodel!
Knock, knock. Who's there? Hatch. Hatch who? Bless you
Knock, knock. Who's there? Spell. Spell who? If you insist: W-H-O
And of course the pièce de résistance must be:
Knock, knock. Who's there? Nobel. Nobel who? Nobel . . . that’s why I knocked!
Quotations About Doorbells
You can often learn a lot about the impact of an invention on society by listening to what people have said about it during its evolution and integration into daily life. Here are some of my favorites about the doorbell.
“The more Susan waited, the more the doorbell didn’t ring. Or the phone.”—Douglas Adams
“Dogs have important jobs, like barking when the doorbell rings, but cats have no function in a house whatsoever.”—W. Bruce Cameron
“Democracy means that if the doorbell rings in the early hours, it is likely to be the milkman.”—Winston Churchill
“Kissing’s a good thing, man. It’s the doorbell of intimacy.”—Thomas Haden Church
“Earth is God’s doorbell. Unfortunately, half the time nobody’s home.”—Beryl Dov
“When the doorbell rings at three in the morning, it’s never good news.”—Arthur Horowitz
“Never knock on death’s door. Ring the doorbell then run. He totally hates that.” —Darynada Jones
“If you think there are no new frontiers, watch a boy ring the front doorbell on his first date.” —Richard Miller
“Edgar Allan Poe described the raven ‘gently rapping at my chamber door.’ The poem’s gothic tone would have been disrupted, had the bird used a doorbell.”—Thomas Mitchell
“Opportunity tends to knock once, then it’s gone . . . however, temptation likes to stand there and lean on the damn doorbell.”—Sarah Moores
“Calm down. Ghosts don’t ring the doorbell.”—Kelly Moran
“What we weave in solitude is unraveled by the doorbell’s ringing.”—Mel Nicolai
“The reason to have a home is to keep certain people in and everyone else out. A home has a perimeter. But sometimes our perimeter was breached by neighbors, by Girl Scouts, by Jehovah’s Witnesses. I never liked to hear the doorbell ring. None of the people I liked ever tuned up that way.”—Jenny Offill
“There are moments in a woman’s life when her heart flips in her chest, when the world suddenly seems uncommonly pink and perfect, when a symphony can be heard in the tinkle of a doorbell.”—Julia Quinn
“There is nothing like a doorbell to precipitate the potential into the kinetic.”—Wallace Stegner
“When someone rings the doorbell, my dog always assumes it’s for him.”—Unattributed
Doorbell and Computing
With the adoption of the internet of things, a number of internet-connected doorbell systems, known as “smart doorbells” (or simply “smartbells”), have appeared in the market. In addition to the traditional pushbutton, in general, these units contain an HD camera, PIR sensor, and WIFI electronics. The smart doorbell is connected to a wi-fi network such that notification of a button push, or indeed any movement whatever in the vicinity of the unit, is instantly sent to a designated smartphone, table, or other suitable electronic devices. When a notification is received, the user will typically see a live video stream from the smart doorbell that clearly shows who is at or near the door, permitting them to engage in a two-way conversation.
The video is typically recorded directly to a cloud internet service. Thus, if the smartbell is in any way tampered with, damaged, or stolen, the event is captured and can be immediately analyzed to determine the identity of the person or persons involved.
