City dwellers spend nearly every moment of every day awash in wi-fi signals. Homes, streets, businesses, and office buildings are constantly blasting wireless signals every which way for the benefit of nearby phones, tablets, laptops, wearables, and other connected paraphernalia.
When those devices connect to a router, they send requests for information—a weather forecast, the latest sports scores, a news article—and, in turn, receive that data, all over the air. As it communicates with the devices, the router is also gathering information about how its signals are traveling through the air, and whether they’re being disrupted by obstacles or interference. With that data, the router can make small adjustments to communicate more reliably with the devices it’s connected to.
But it can also be used to monitor humans—and in surprisingly detailed ways.
As people move through a space with a wi-fi signal, their bodies affect it, absorbing some waves and reflecting others in various directions. By analyzing the exact ways that a wi-fi signal is altered when a human moves through it, researchers can “see” what someone writes with their finger in the air, identify a particular person by the way that they walk, and even read a person’s lips with startling accuracy—in some cases even if a router isn’t in the same room as the person performing the actions.
by John Wesley Hall
Criminal Defense Lawyer and
Search and seizure law consultant
Little Rock, Arkansas
Contact: forhall @ aol.com / The Book www.johnwesleyhall.com
"If it was easy, everybody would be doing it. It isn't, and they don't." —Me
"Life is not a matter of holding good cards, but of playing a poor hand well." –Josh Billings (pseudonym of Henry Wheeler Shaw), Josh Billings on Ice, and Other Things (1868) (erroneously attributed to Robert Louis Stevenson, among others)
“I am still learning.” —Domenico Giuntalodi (but misattributed to Michelangelo Buonarroti (common phrase throughout 1500's)).
"Love work; hate mastery over others; and avoid intimacy with the government."
—Shemaya, in the Thalmud
"It is a pleasant world we live in, sir, a very pleasant world. There are bad people in it, Mr. Richard, but if there were no bad people, there would be no good lawyers."
—Charles Dickens, “The Old Curiosity Shop ... With a Frontispiece. From a Painting by Geo. Cattermole, Etc.” 255 (1848)
"A system of law that not only makes certain conduct criminal, but also lays down rules for the conduct of the authorities, often becomes complex in its application to individual cases, and will from time to time produce imperfect results, especially if one's attention is confined to the particular case at bar. Some criminals do go free because of the necessity of keeping government and its servants in their place. That is one of the costs of having and enforcing a Bill of Rights. This country is built on the assumption that the cost is worth paying, and that in the long run we are all both freer and safer if the Constitution is strictly enforced."
—Williams
v. Nix, 700 F. 2d 1164, 1173 (8th Cir. 1983) (Richard Sheppard Arnold,
J.), rev'd Nix v. Williams, 467 US. 431 (1984).
"The criminal goes free, if he must, but it is the law that sets him free. Nothing can destroy a government more quickly than its failure to observe its own laws,
or worse, its disregard of the charter of its own existence." —Mapp
v. Ohio, 367 U.S. 643, 659 (1961).
"Any costs the exclusionary rule are costs imposed directly by the Fourth Amendment."
—Yale Kamisar, 86 Mich.L.Rev. 1, 36 n. 151 (1987).
"There have been powerful hydraulic pressures throughout our history that
bear heavily on the Court to water down constitutional guarantees and give the
police the upper hand. That hydraulic pressure has probably never been greater
than it is today."
— Terry
v. Ohio, 392 U.S. 1, 39 (1968) (Douglas, J., dissenting).
"The great end, for which men entered into society, was to secure their
property."
—Entick
v. Carrington, 19 How.St.Tr. 1029, 1066, 95 Eng. Rep. 807 (C.P. 1765)
"It is a fair summary of history to say that the safeguards of liberty have
frequently been forged in controversies involving not very nice people. And
so, while we are concerned here with a shabby defrauder, we must deal with his
case in the context of what are really the great themes expressed by the Fourth
Amendment."
—United
States v. Rabinowitz, 339 U.S. 56, 69 (1950) (Frankfurter, J., dissenting)
"The course of true law pertaining to searches and seizures, as enunciated
here, has not–to put it mildly–run smooth."
—Chapman
v. United States, 365 U.S. 610, 618 (1961) (Frankfurter, J., concurring).
"A search is a search, even if it happens to disclose nothing but the
bottom of a turntable."
—Arizona
v. Hicks, 480 U.S. 321, 325 (1987)
"For the Fourth Amendment protects people, not places. What a person knowingly
exposes to the public, even in his own home or office, is not a subject of Fourth
Amendment protection. ... But what he seeks to preserve as private, even in
an area accessible to the public, may be constitutionally protected."
—Katz
v. United States, 389 U.S. 347, 351 (1967)
“Experience should teach us to be most on guard to
protect liberty when the Government’s purposes are beneficent. Men born
to freedom are naturally alert to repel invasion of their liberty by evil-minded
rulers. The greatest dangers to liberty lurk in insidious encroachment by men
of zeal, well-meaning but without understanding.”
—United
States v. Olmstead, 277 U.S. 438, 479 (1925) (Brandeis, J., dissenting)
“Liberty—the freedom from unwarranted
intrusion by government—is as easily lost through insistent nibbles by
government officials who seek to do their jobs too well as by those whose purpose
it is to oppress; the piranha can be as deadly as the shark.”
—United
States v. $124,570, 873 F.2d 1240, 1246 (9th Cir. 1989)
"You can't always get what you want /
But if you try sometimes / You just might find / You get what you need."
—Mick Jagger & Keith Richards
"In Germany, they first came for the communists,
and I didn't speak up because I wasn't a communist. Then they came for the Jews,
and I didn't speak up because I wasn't a Jew. Then they came for the trade unionists,
and I didn't speak up because I wasn't a trade unionist. Then they came for
the Catholics and I didn't speak up because I wasn't a Catholic. Then they came
for me–and by that time there was nobody left to speak up."
—Martin Niemöller (1945) [he served seven years in a concentration
camp]
“You know, most men would get discouraged by
now. Fortunately for you, I am not most men!”
---Pepé Le Pew
"The point of the Fourth Amendment, which often is not grasped by zealous officers,
is not that it denies law enforcement the support of the usual inferences which
reasonable men draw from evidence. Its protection consists in requiring that
those inferences be drawn by a neutral and detached magistrate instead of being
judged by the officer engaged in the often competitive enterprise of ferreting
out crime."
—Johnson
v. United States, 333 U.S. 10, 13-14 (1948)
