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The Consumer Electronics Hall of Fame: Casio F-91W Wristwatch

For about $10, this watch can do something that most luxury watches cannot: keep accurate time to within 1 second a day

3 min read
The Casio F-91W
Value Proposition: The Casio F-91W was introduced in 1989 and is still sold in its original form three decades later. For about US $10, it offers impressive accuracy along with an alarm, stopwatch, and day/date display.
Photo: Getty Images

The CasioF-91W digital wristwatch is a triumph of adequacy. It’s plain, utilitarian, and utterly dependable. When it was introduced in 1989 it sold for about US $20. Today—yes, it is still being manufactured 30 years after its introduction—you can get one for a little more than $10.

The best mechanical watches, some of which cost a lot more than $100,000, are accurate to within about 2 seconds a day. The average watch with a quartz movement, such as the F-91W, is accurate to within 1 second a day, which is the accuracy that Casio claims for the F-91W. It’s more accurate than anyone looking to spend a sawbuck on a watch should reasonably expect.

When it was introduced, it had a basic set of features, which included a daily alarm, an auto calendar, day/date display, and a stopwatch that does splits and marks time in hundredths of a second. It has three buttons, and if you’re reasonably bright you probably won’t need the manual to figure out what they do. But don’t ignore the manual [PDF], because it has one of the more entertainingly assertive notes concerning operator error in the consumer electronics industry:

“THERE IS NO WAY unit components can be damaged or malfunction, due to misoperation of buttons. If confusing information appears on the display it means entry sequence was incorrect. Please read the manual and try again.”

Well, okay then. Also, with newer versions, if you hold down the button on the right-hand side of the watch for several seconds, the display spells out “Casio,” a feature that supposedly indicates that the watch is a legitimate Casio product, instead of a counterfeit. (Strange but true: Even a $10 watch is vulnerable to counterfeit.) The F-91W’s LCD screen is clearly readable in the daytime, and at night there’s a greenish backlight that’s entirely adequate.

From the very first model three decades ago, none of that has changed. Nor has Casio ever changed the design. The common version of the watch has always had a black plastic case and a stainless-steel back. There have been versions with plastic cases produced in a color other than black, and also models with all-metal cases. But that’s it as far as fancy embellishment goes.

At precisely one-third of an inch thick, the F-91W is relatively thin and flat, compared to the hunky wristwatches popular today. It’s neither ugly enough to be shunned nor attractive enough to qualify as stylish. These days the watch gets lauded for its retro style, but that’s hard to credit. Can any item’s style be called “retro” when it simply hasn’t changed in three decades? Casio describes the design as “tried and true.”

It is water resistant. The battery lasts about seven years. Customers commend its resin strap for its longevity. The watch earns admiration for being durable and reliable. Granted, when applied to a wristwatch, “durable” and “reliable” are considerably fainter praise than “sexy” and “glamorous.” But did we mention that it costs $10? And, furthermore, there are photos of a prepresidential Barack Obama wearing it.

The watch does have something of a checkered past. In the mid-1990s, the F-91W became briefly notorious as “the terrorist watch.” Extremists in Pakistan and the Philippines learned how to use the F-91W as a timer for improvised explosive devices. The watch endured the bad publicity. More than 20 years later, it’s a bit of trivia that has faded from the consciousness of the watch-buying public.

Casio has never provided sales figures for its watches, nor has it revealed its manufacturing output. That said, a commonly cited estimate holds that the company has been producing roughly 3 million F-91Ws a year. Production levels have certainly varied over the years, but that 3 million figure, multiplied by 30—the number of years the watch has been available—gives a ballpark estimate: 90 million F-91Ws shipped. Even if that’s too high by millions, Casio has sold an astounding number of F-91Ws in a market with hundreds, maybe thousands of manufacturers and countless different models all told.

Today, the Casio F-91W is typically the first- or second-best-selling watch on Amazon (the “Casual Sport” version of the F-91W also ranks in the top 50). And it is still consistently included in reviewers’ lists of the best digital watches, invariably in the category of “best value.”

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The Indian Startup Pulling Water From the Air

Uravu’s new 1,000-liter-per-day unit will come on line this month

5 min read
two men standing in front of a metal box system

Uravu cofounders Govinda Balaji [left] and Swapnil Shrivastav stand beside several of their absorber units.

Edd Gent

BENGALURU, India—Technology that can pull water out of thin air could help solve the world’s growing water scarcity problem, but most solutions are expensive and difficult to scale. Indian startup Uravu Labs says its low-cost modular approach could provide a blueprint for more affordable and sustainable atmospheric water harvesting. What comes out of the pipe, the company’s website says, is “100 percent renewable water”—renewably powered, harnessed from a vast and nearly inexhaustible source, and with no wastewater produced in the process.

Uravu is putting the finishing touches on its biggest unit to date. The device, the company says, will be capable of harvesting up to 1,000 liters of water a day when it goes online later this month, at its headquarters in the south Indian city of Bengaluru. By the end of the year the company hopes to scale that up to 10,000 L a day, says cofounder Swapnil Shrivastav.

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Building the Future of Smart Home Security

Engineers must invent new technology to enhance security products’ abilities

4 min read
One engineer peers into a microscope to work on a small circuit while another engineer looks on

In this article, SimpliSafe’s VP of Software Engineering discusses his team’s focus on creating a safer future through enhanced technology.


This is a sponsored article brought to you by SimpliSafe.

It’s nearly impossible to find a household today that doesn’t have at least one connected smart home device installed. From video doorbells to robot vacuums, automated lighting, and voice assistants, smart home technology has invaded consumers’ homes and shows no sign of disappearing anytime soon. Indeed, according to a study conducted by consulting firm Parks Associates, smart home device adoption has increased by more than 64 percent in the past two years, with 23 percent of households owning three or more smart home devices. This is particularly true for devices that provide security with 38 percent of Americans owning a home security product. This percentage is likely to increase as 7 in 10 homebuyers claimed that safety and security was the primary reason, after convenience, that they would be seeking out smart homes, according to a report published by last year.

As the demand for smart home security grows, it’s pertinent that the engineers who build the products and services that keep millions of customers safe continue to experiment with new technologies that could enhance overall security and accessibility. At SimpliSafe, an award-winning home security company based in Boston, Mass., it is the pursuit of industry-leading protection that drives the entire organization to continue innovating.

In this article, Nate Wilfert, VP of Software Engineering at SimpliSafe, discusses the complex puzzles his team is solving on a daily basis—such as applying artificial intelligence (AI) technology into cameras and building load-balancing solutions to handle server traffic—to push forward the company’s mission to make every home secure and advance the home security industry as a whole.

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