Mission Statement - De-Spinning the Pro-Taser Propaganda

Yeah right, 'Excited Delirium' my ass...

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The primary purpose of this blog is to provide an outlet for my observations and analysis about tasers, taser "associated" deaths, and the behaviour exhibited by the management, employees and minions of Taser International. In general, everything is linked back to external sources, often via previous posts on the same topic, so that readers can fact-check to their heart's content. This blog was started in late-2007 when Canadians were enraged by the taser death of Robert Dziekanski and four others in a short three month period. The cocky attitude exhibited by the Taser International spokespuppet, and his preposterous proposal that Mr. Dziekanski coincidentally died of "excited delirium" at the time of his taser-death, led me to choose the blog name I did and provides my motivation. I have zero financial ties to this issue.

Friday, January 15, 2010

Q: How many amps in a police taser?

A: "2.1 mA."

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The above answer is a vast oversimplification and is thus misleading.

There are two tasers in common use by officers. The M26 was introduced in 1999, and the X26 was introduced in 2003. There are others, such as the XREP projectile, and the X3 released in 2009.

There are several ways to measure complex waveforms. The "2.1 mA" mentioned above is the Average. In general, electrical engineers do not use simple averages, even if rectified, because they most often provide a misleading number.

It's fair to state that Averages in this context are the mark of a newbie, or someone with something to hide. They're that misleading.

The most common method of measuring complex waveforms is something called RMS (root mean square). For example, the voltage in your house is probably 120 or 240 volts RMS. This concept is explained in first year EE courses. All reputable brand digital meters in common use by EEs provide the RMS function.

Both the M26 and X26 are about 150 to 160 mA when measured using RMS.

This 150+ mA range might raise eyebrows, because it's clearly a number that is well above the safe limits of around 30 mA.

Part of the safety claim made by the manufacturer is that the output waveform consists of very short pulses (100us) of high frequency (50kHz), and these two waveform characteristics provides an increased level of safety margin.

Problem is... the X26 waveform has a DC pulse after the arc phase. This DC pulse is low frequency (19 Hz) and continuous 100% duty cycle. So the X26 taser is clearly less safe than the older M26 (even the manufacturer's own expert confirmed this fact). I believe that their in-house experts forgot about Fourier transforms and neglected to account for this DC pulse. They continued to proclaim "short pulses" well past 2003.

So the real question being asked is: What's the Effective current?

By the effects, the taser's Effective current is well above "2.1 mA". The taser usually does much more than just a harmless tickle. As I said, "2.1 mA" is misleading. The implicit claim that the Effective is the Average is simply preposterous.

The Effective current is self-evidently well above the level of excruciating pain (way above and beyond). It's also obviously well above the level where muscle lock-up occurs (that's the whole point). And there's growing evidence that the effective current might be enough to sometimes affect the heart (this is the very next step on the scale, right next to muscle lock-up).

The manufacturer claims that the waveform has special (magical?) characteristics to ensure safety. This seems unlikely since the M26 and X26 waveforms are so different. And there's a newer X3 model that reportedly emits about 40% less charge than the X26. So that claim is falling apart for numerous reasons (inconsistent, obviously preposterous).

It's worth noting that the taser-associated death rate was much less than one per month up until 2003. Starting in 2003, strangely coincident with the introduction of the X26 taser, the taser "associated" death rate ramped up to about 7 per month and has been at about that rate ever since.

It's also worth noting that the taser, assuming it did kill, would leave no explicit postmortem clues. So some folks would be able to invoke alternate explanations such as "excited delirium" to explain the deaths. They could enforce this by means of lawsuits against coroners that dare to find the taser a cause of death.

The whole issue is extremely complicated and there's a lot of history.

But the claim that the taser current is "2.1 mA" is very very wrong.

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