Software that monitors employees who work at home. Electronic gear that tracks everywhere they go and how they drive while on the job. Technology that records their fitness and “happiness levels.”

Employers are rushing to embrace the Internet of Things, with its array of smart gadgets, to keep watch on their workers. Studies contend that these devices help reduce theft, boost productivity and weed out lazy, incompetent or abusive employees. Many managers swear by them, including Eric Weakley, owner of R&A Trucking in Oakland, who has outfitted his vehicle fleet with onboard recorders that alert him if the trucks suddenly brake or do something else unusual.

“If the driver is driving too fast or if someone just cut them off,” Weakley said, “we can call the driver and say, ‘Hey, is there anything we should know about?’ “

But other studies conclude that such monitoring can be so intrusive it undermines an employee’s work and well-being, producing anxiety or even depression. The U.S. Office of Technology Assessment, a now-defunct advisory branch of Congress, warned that the trend might lead to poor office morale, staff turnover, worker slowdowns and even “employee sabotage.”

Jerome McDonough, a University of Illinois expert in human-computer interaction, termed the technology “a new form of panopticon for employees” — referring to a type of prison where the inmates all can be watched without them knowing it — adding that it’s “very troubling.”

Over the years, courts have given employers broad discretion to electronically monitor their employees while they’re working. Legislators have been reluctant to change that, despite the growing array of surveillance technologies that bosses are adopting.

“The law is very slow to react,” said Corey Ciocchetti, a University of Denver associate professor of business ethics and legal studies. He predicts that “it’s only getting worse for employees.”

Such computerized checking had been building long before the Internet of Things. In recent years, growing numbers of employers have been watching every website their workers visit, email they send, computer keystroke they make and document they review or print. Others have engaged in “backspace and delete-button monitoring,” believing that “the more employees strike these buttons, the less efficient these employees are,” according to a Ciocchetti study.

In the past, this electronic auditing focused on workers in call centers, factories, restaurants and other relatively low-wage jobs. But the practice has become much more widespread, as smart devices hitting the market have become more numerous, easier to use and far more capable of analyzing workers.

Of 304 companies in a range of industries surveyed by the American Management Association in 2007, 45 percent said they track employee keystrokes, time spent at the keyboard and phone numbers called. In addition, 43 percent checked their employees’ email, and stored and reviewed their computer files. Since then, experts say, the extent of employee monitoring has increased steadily due largely to the growing array of data-gathering gadgets known as the Internet of Things.

When this newspaper asked the Bay Area’s 10 largest tech companies if they electronically monitor their employees’ performance, Intel and Cisco Systems said they do not. The rest — Hewlett-Packard, Apple, Google, Oracle, eBay, Applied Materials, Gilead Sciences and Synnex — either declined to comment or did not respond.

Nonetheless, tech is joining the trend, according to Las Vegas-based Time Doctor. It says that tech firms are among the more than 1,000 California companies using its software to detect employees surfing personal websites and to flash them a note it calls “a nudge to ensure they are still working,” such as, “Hi! Are you working on preparing for the meeting?”

Other employers monitor their staffs with cameras concealed in clocks, smoke detectors, picture frames, air fresheners, coat hooks and coffee pots. Besides helping spot thieves and safety problems, the devices can reveal “if someone is not working at their peak,” said John Carr of Goodwill Industries of Silicon Valley, which has cameras — most of them in plain view — in all its facilities.

Increasingly, such monitoring isn’t limited to corporate offices. Of 300 business officials surveyed in 2012 by consulting firm Frost & Sullivan, 36 percent said they use global positioning or other devices “to locate and manage mobile field workers,” and another 27 percent planned to do so soon.

Some companies use software to track what their employees do when working on their computers at home, including which websites they visit and how much time they spend on assigned tasks, according to firms that make the monitoring programs. Edward Kwang, president of MySammy — a Walnut-based company that offers such technology — said he even uses it to supervise his own at-home employees.

“It’s extremely important for me,” he said. “Otherwise, I have no way to measure their time. I would just rely on their good faith.”

Several technology consulting firms also encourage their customers to install the devices on their employees’ home computers to ensure, in part, that the workers are properly attired in their houses. As asserted by one of the companies, New York-based Directive, “a person who dresses up for work from their home will have a more productive workday.”

Bosses also are scrutinizing their workers’ tones of voice and emotions.

With Hitachi’s “Business Microscope,” a badge crammed with sensors that workers wear, employers can track who their employees talk to, how often, where and “how energetically,” the company notes in a news release.

Among those who have tried it on some of their workers is Michigan office-furniture company Haworth and several of its clients, including a Silicon Valley telecom company, said Haworth manager Gabor Nagy. He called the device useful because it measures how well different workers interact, adding, “if you collaborate, it leads to innovation.”

CallFinder of Burlington, Vermont, says it helps Fortune 500 firms, cosmetic surgeons, car dealers and other companies analyze phone conversations to understand “what kind of tones of voice an employee should use,” adding that the process “can inspire an employee to perk up and sound more interested in the customer.”

And then there is Matilda, a robot created by Australia’s La Trobe University with help from Japanese company NEC. It’s designed to conduct interviews with prospective job candidates and develop an “emotional profile” of them based on such factors as their “intensity of expressions and “body language,” according to La Trobe professor Rajiv Khosla, noting that some companies have expressed interest in using the robot.

Monitoring workers’ fitness is increasing, too.

British firm The Outside View urges its employees to download smartphone apps that track how much they sleep, walk, run, eat and sit at their desks — as well as their self-reported “happiness levels.” Other companies, including Practice Fusion of San Francisco and AutoDesk of San Rafael, ﻿encourage their workers to wear fitness devices to record how much exercise they get, insisting the idea is purely voluntary.

“We’ve seen tremendous employee engagement” in the program, said Megan Granat, Practice Fusion’s benefits and wellness manager, noting that about two-thirds of the company’s workers participate.

How much this data is seen by employers varies from company to company, although the firms say they often let their employees decide how much information to disclose and often aggregate the data after stripping it of any personally identifiable facts.

But University of Maryland law professor Frank Pasquale said that even when the data gathering is voluntary, many workers will feel compelled to participate, fearing their bosses will suspect they’re hiding something if they refuse.

“Eventually the game gets to where everybody has to do it,” he said. “You have to nip it in the bud or very rapidly it becomes the norm.”

Although companies often reward employees who participate in workplace-wellness programs with lower health insurance costs, some experts fear workers’ premiums may be jacked up if their gadgets reveal they have medical problems.

A Robert Wood Johnson Foundation study concluded that such wellness programs are expanding because the Affordable Care Act of 2010 requires companies that don’t meet their health goals to pay more for insurance. The report cited concerns that the trend “could discriminate against low-income individuals or racial and ethnic minorities,” who are “more likely to have the health conditions that wellness programs target and also may face more difficult barriers to healthy living.”

Tracking workers could become more intrusive in the future. Some tech experts and privacy advocates believe that bosses eventually will seek to monitor employees with smart clothing and perhaps even ingestible devices or implantable microchips. After Cincinnati video surveillance company Citywatcher.com required some of its employees to get chip implants in 2006, California and several other states passed laws forbidding anyone from forcing their workers to receive chip implants.

Employers maintain that they have good reason for monitoring their workers.

A Burst Media survey of 11,500 adults found that more than half do web shopping and send personal emails while at their jobs. In another study by security firm Proofpoint, 35 percent of the 261 U.S. employers surveyed said they had investigated a suspected email leak of confidential information in the past year. And recent court cases have found companies legally vulnerable to sexual harassment suits if their employees use work computers to access and share sexually offensive material.

Some studies contend monitoring is beneficial.

When researchers last year examined the use of employee-tracking gadgets at 392 restaurants, they found the devices reduced theft by 22 percent and boosted revenue by 7 percent on average. Safety is another reported plus. A Virginia Tech Transportation Institute study of DriveCam — a video camera used by San Francisco Municipal Transportation Agency buses and Waste Management’s garbage trucks to record what happens in front of and inside the vehicles — determined the device can cut fatal accidents by 20 percent.

“It records only when there’s a driving irregularity like a sudden stop, a swerve, collision, etc.,” said Greg Lund of San Diego-based Lytx, which makes DriveCam. He added that Lytx reviews the recording and “if it’s determined to be a ‘risky driving event,’ the video is sent to the fleet manager who uses it as a coaching tool to help the driver see what happened and, if need be, correct it.”

But a British study of 557 customer service representatives whose bosses track their calls concluded that excessive monitoring can make employees anxious, depressed and “less active.” Other studies have found that monitoring can cause employees exhaustion, indigestion, back pain, sore arms and legs, numbness in fingers and wrists, and make them less willing to take creative risks.

“The very act of being measured, being put under the microscope, changes behavior, sometimes in a good way, sometimes in a bad way,” said Harikesh Nair, professor of marketing at Stanford, noting that more studies are needed to assess the implications of such scrutiny.

The locator badges that Mills-Peninsula Health Services’ Burlingame hospital began requiring nurses to wear several years ago illustrates the opportunities and concerns the new technology raises. The devices make it much easier to find nurses in emergencies, and “we’re here to do the best thing for our patients,” said Chief Nursing Officer Vicki White.

But Genel Morgan, a former nurse and union steward at the hospital, said the gadgets contributed to her decision to retire last year at age 66. While acknowledging their usefulness, she viewed them with apprehension.

“I feel it’s Big Brother lurking,” she said. “I was paranoid enough to believe they were going to use it as a disciplinary thing in the future” even though she questioned the badge’s accuracy, adding that it sometimes “showed a nurse was in a location when she was no longer there.”

Despite their wide legal latitude to monitor workers, in some cases employers are being sued over their surveillance.

A federal suit filed this year asserted that the Chicago Transit Authority, while checking for goof-offs, secretly videotaped five electricians in an electrical room equipped with lockers that they used to change their clothes. The agency has denied violating their privacy.

In another case, a congressional report in February blasted the U.S. Food and Drug Administration for “overly invasive monitoring” of personal computer communications by employees who had complained to Congress and others that the FDA was approving unsafe medical devices. FDA spokeswoman Erica Jefferson said “the agency had a reasonable basis for conducting its monitoring.”

Forrester Research analyst J. P. Gownder believes most employers will refrain from using technology to bird-dog their employees, because “people are going to vote with their feet and not want to work for a company that is overly snooping.”

But others say such spying is quickly accelerating.

“What you do at work has never been private and it’s going to be even less private in the future,” said Lewis Maltby, president of the National Workrights Institute, adding that with technology available today, “your boss could track you every minute of your life.”

Contact Steve Johnson at 408-920-5043. Follow him at Twitter.com/steveatmercnews.