[nfb-talk] Way-finding devices for buildings

[Michael Bullis]

Many of us have talked about developing a device for way-finding that would,
for example, help us find our way back from a podium to our seat, or to some
location earlier visited in a building.

Such a device would also be handy in a large field where one would like to
return to a starting point.

The difficulty has been that gps simply doesn't provide enough specificity,
pretty much limited to an eleven foot area.  When finding a seat, 11 feet
isn't quite adequate.  The other issue is that gps doesn't work in tall
buildings.

 

This article from Tech Review for 8/19 might provide a direction.  The nice
thing is that it's not for blind people so would have broader appeal and
lower cost in the long run.

 

    Finding Our Way with Digital Bread Crumbs

 

    A Microsoft research project explores whether sensors in mobile devices

    could help us navigate without GPS.

 

    By Evan I. Schwartz

 

    In the classic tale by the Brothers Grimm, Hansel and Gretel leave a

    trail of bread crumbs from their home so as not to get lost in the

    forest, but the plan fails when birds eat the crumbs. In the modern

    world, a GPS device could assist the fabled siblings. But what if they

    wandered into a place without GPS signals?

 

    With that kind of problem in mind, a team of researchers at Microsoft

    set out to create a mobile device that could forge a trail of "digital

    bread crumbs." The device would collect the trail data while the user

    walked indoors, underground, or in other spaces where GPS signals are

    unavailable or weak--such as multilevel parking garages that can baffle

    people who forget where they parked.

 

    The resulting Microsoft Research device, a prototype phone called

    Menlo, packs a suite of sensors: an accelerometer to detect movement, a

    side-mounted compass to determine direction, and a barometric pressure

    sensor to track changes in altitude.

 

    While existing phones contain some of these sensors, what's new about

    Menlo is an app called Greenfield, which aims to solve the Hansel and

    Gretel problem by harnessing the data from the sensors. The goal is to

    count a user's sequence of steps, gauge direction changes, and even

    calculate how many floors the user has traversed by stairs or an

    elevator. The app stores the trail data so that a user can later

    retrace his path precisely.

 

    The researchers call Greenfield an example of "activity-based

    navigation." In a paper to be presented at the MobileHCI conference in

    Lisbon, Portugal, next month, the Microsoft team positions Greenfield

    as an ideal method of navigation in places where maps haven't been

    constructed or aren't accessible. For the paper, [3]computer scientist

    A.J. Brush and her team conducted a trial in which people had to

    retrieve an object from a colleague's parked car in a large garage,

    using the coworker's trail data to navigate the way.

 

    "I knew this was possible, but I was wondering when someone would put

    all the pieces together," says Jeff Fischbach, a forensic technologist

    with [4]SecondWave Information Systems, a consulting firm in

    Chatsworth, CA. Fischbach often serves as an expert witness in criminal

    trials in which GPS data is used as evidence. He says that trail data

    from an app like Greenfield could help determine whether a murder

    suspect is truthfully stating an alibi. "This kind of data is terrific

    for convicting people and terrific at exonerating people."

 

    But since such trail data can be retrieved, transmitted to the

    Internet, and even subpoenaed by the government, this raises the most

    extreme sort of privacy issues. "How can you control who has access to

    the data?" Fischbach says. And would employers use it to keep close

    track of their workers?

 

    The potential applications are numerous. Greenfield could be used for

    new kinds of urban street games, to recover lost items, to find friends

    at a stadium, or to rescue hikers and mountain climbers. The

    researchers cite a 2002 book, [5]Inner Navigation, by engineer Erik

    Jonnson, who argues that everyone struggles with creating "cognitive

    maps." Even those who have an excellent sense of direction can be

    tricked by their own recall, sometimes remembering landscapes in

    precisely opposite layouts. "I think people have an inner compass,"

    Jonnson says, "and when it goes wrong, the most amazing things happen."

 

    In their test at two different parking garages--one with GPS signals

    and one without--the Microsoft team started subjects in an adjacent

    office building and handed each of them a piece of paper listing the

    color, make, model, and license plate number of a colleague's car.

    (This kind of problem was familiar to most of the study's participants;

    one said that losing track of a car in a garage is "catastrophic.") The

    subjects were given a Menlo device running Greenfield, which had

    recorded an activity trail, for use in retracing the way back. In some

    cases, the trail data was enhanced by photographs taken along the

    route.

 

    Every participant in the study found every car, at least eventually.

    But since several configurations of bread-crumb data were tested, there

    was wide variation in how long it took each subject, depending on what

    kind of information was displayed. Even when they were told what garage

    floor and quadrant the car was on, subjects often forgot and had to

    rely on the device for direction.