Chicago - Taser International Inc. has applied embedded intelligence to the lowly stun gun, reversing the Scottsdale, Ariz., company's fortunes but also catapulting it into the national-news spotlight. The combination of signal processing and a "shaped-pulse" output profile has made the stun gun smaller, more efficient and more desirable to police forces, Taser's biggest customers, experts said last week.

In rolling out the X26 last spring, the company eliminated the need for a heavy battery pack while delivering the same amount of electrical energy as the existing M26 model. To do that, Taser's engineers endowed the gun with two separate energy pulses. An initial pulse delivers a high-voltage arc capable of penetrating clothing, yet employs a minuscule electrical current, the better to reduce the power consumption. It is only after the establishment of that electric arc " and after the impedance has dropped to near zero " that the system delivers its second phase: a low-voltage, high-current pulse able to stimulate human tissue.

Moreover, engineers replaced the eight AA batteries of the earlier model with two small Duracell CR123 lithium cells, like those used in cameras. The new unit weighs a scant 7 ounces, compared with 18 for the earlier model, and is about 40 percent of the old one's volume. "By being that much smaller, the new Taser is easier to carry and officers are more likely to carry it on their belt, rather than leave it in their car," said Sgt. Paul Hopkins of the Orange County Sheriff's Department in Florida. After law enforcement agencies began snapping up the new stun guns at unprecedented rates late last year, Taser's once-languishing stock price shot up by a whopping 7,000 percent. Then two families filed wrongful-death suits against Taser, and news outlets began hammering the company with stories of stun-gun-related deaths. The stock price plummeted to less than half its peak value, though still far above the sub-$1 level of 12 months before. "The huge stock trajectory started with the introduction of the new technology a year ago," said analyst Joe Blankenship, vice president of research for Source Capital Group Inc. (Scottsdale). "It made police forces say, 'Now we can use this.' "

The sudden rise of the X26 is seen as a testament to the power of embedded technology and a sign that even the most unlikely products can benefit from the addition of a little electronic intelligence.

"A few years ago, we had nothing," said Patrick Smith, Taser's chief executive officer. "Then we redesigned the product, and everything came together in a way we couldn't have imagined."

Of the 18,800 police agencies in the United States, 24 percent now use Tasers. The company says it has placed about 65,000 units in the field, with countless enforcement agencies now pondering broader use of the guns. What's more, police in England are also said to be considering them. "Over the next few years, you'll see every bobby carrying one, as well as almost every police officer in the U.S.," predicted Phil Smith, chairman of Taser (and the father of CEO Patrick Smith).

Still, the Taser's newfound popularity hasn't always been the source of good news. Shortly after its stock price soared from the equivalent of 90 cents a share (taking into account a stock split) to $64 a share in under a year, Taser was rocked by news reports that linked its stun guns to more than 40 deaths. CBS Evening News, The Wall Street Journal, Barron's Online and other news organizations suggested the gun's charge might be too much for people who were already agitated or on drugs.

"There may be a small group of people that, once it's used, may develop difficulties that may result in death," said a coroner in a CBS report. Taser has rebutted the charges (see story, below), but its stock tumbled to $31 following the news reports.

Nevertheless, many analysts continue to issue "buy" ratings, calling the stock's success amazing, even now. "You don't find many stocks that grow 3,400 percent in one year," said Source Capital's Blankenship, referring to the current stock price. "Nothing matches it in terms of percentage gain."

A little over a year ago, analysts said, the 18-ounce M26 Taser was too big to be carried on a typical officer's belt, and most cops didn't want them. "It was like the old Motorola 'brick' cell phone," said CEO Patrick Smith. "A great concept, but just too big."

Smith, who holds a biology degree from Harvard as well as two MBAs, spent a decade directing redesigns before finally settling on the current version. That didn't happen, however, until after Smith and other Taser executives felt the sting of repeated failure, when early versions failed to stop law enforcement volunteers during demonstrations designed to showcase the stun gun's effectiveness.

After enough such humiliations, company brass reached a consensus on the bigger M26 unit, which needed eight AA alkaline batteries to produce enough electrical energy to disable determined criminals. "If someone's mentally focused enough, or on drugs, they can fight through it if you don't apply enough current," Smith said.

The new, smarter X26 sheds that battery pack to attain a compact profile. Taser said that it has cut power consumption from about 26 watts to as low as 5 W. Each of the two pulses minimizes power consumption, executives said, because high voltage and high current are never employed together. Instead, the X26 uses high voltage with low current to overcome the initial impedance, and then combines high current with low voltage to stun the victim.

The key to delivering the two shaped pulses lies in a digital technique for control. During operation, a Texas Instruments 16-bit RISC mixed-signal processor known as the MSP430 monitors a feedback line from the high-voltage section of the gun. When the microcontroller detects a discharge, it records the time and then ensures there is sufficient lag (about 52 milliseconds) before the next pulse. That's important, engineers say, because the device's analog circuitry tends to try to pack the pulses too close together. To prevent that, the digital controller actually shuts down the power supply for a few milliseconds, then turns it back on when it's time for the next pulse.

"The digital pulse controller delivers a consistent pulse rate, which improves the device's ability to run for a long time, because you're not running the battery at full throttle all the time," CEO Smith explained. Controlling the system in this way, he said, also enables users to administer a more effective shock, since it ensures they can deliver it in recommended 5-second bursts.

Past Tasers were often inappropriately applied because users, in the heat of battle, sometimes forgot to hold down the trigger for a full 5 seconds. The MCU "initiates a 5-second cascade of pretimed pulses when it receives a 'fire' signal," Smith said. "So in essence, it's holding closed the switch that connects the batteries to the output circuit."

Safety debate

Taser International executives said that the device's small size and electronic features, which also include an E2PROM memory and a USB data port to download the weapon's firing history, were so appealing to police forces that the new model began to sell through sheer word of mouth. And that was important, they said, because the company has no conventional sales force.

"These are probably the most skeptical customers on earth," Phil Smith, the company chairman, said. "They don't like salespeople and they weren't going to buy it until they tested it for themselves."

Still, the extraordinary response, which resulted in a 300 percent increase in revenue and a 1,500 percent earnings boost, didn't always translate into good news. CBS News reported last month that at least 40 people have died after being hit with the stun guns. (One of the two wrongful-death suits filed by victims' families has been dismissed; the other is pending.) CBS' report flies in the face of Taser's claim that, after 100,000 uses, the gun has been proven safe.

Taser executives argue that in 39 of the 40 cases CBS cited, the stun gun was not listed as a cause of death. In the 40th case, they said, electrical shock was listed on the coroner's report along with a laundry list of other possible causes, including cocaine intoxication, an enlarged heart and overexertion. Patrick Smith also maintained the other deaths involved drug overdoses.

At the same time, statistics from the Orange County Sheriff's Office in Florida show that the device has actually promoted safety. While the agency's Taser use rose from three cases in 2000 to 228 cases in 2001 and 549 in 2002, injuries to officers have been reduced by 80 percent. Equally important, the department has logged 32 cases where officers could have shot and killed someone, but used the Taser instead.

"There's no doubt that the bad guys are actually benefiting from the use of the Taser," said Hopkins of the sheriff's office. Orange County experienced three in-custody deaths after use of a Taser, he said, but coroners have ruled two of the deaths drug related. A third is awaiting a ruling. Analysts said last week that the short-term effect of the CBS report may have been to bring Taser's stock down to a more reasonable level, where it's not overvalued. Blankenship of Source Capital Group said he changed his position on the stock from a hold to a buy last week after its value fell. "We don't see the CBS report as an issue," Blankenship said. "None of the deaths were directly attributable to the Taser."

The company, meanwhile, has posted a response to the CBS story on its Web site(www.taser.com). "The important thing is that we've gone out and won the faith of the professional market," Patrick Smith said.