IEEE Spectrum October, 2013 - 20

resources_hanDs on

point-and-shoot
weather data
automate data collection
with a camera

aVatar IN aCtIoN: Golf-swing
data is mapped to the motions of
an animated golfer, allowing you to
examine your swing from the back,
the side, and above.

made me feel a bit self-conscious. But
once I got used to checking it, the driving range felt more like a video game. It
was fun to see the path of my swing-
even with all its flaws-from three different angles. In addition to the animation,
the app provides data such as the speed
and angle of the club at impact. It also
has an "analysis" feature, which tries to
identify errors at nine points in the swing.
I now had specific numbers and targets
that I could improve on, or try to repeat.
After numerous swings, however,
I found myself questioning the validity of the SwingTip's results. I noticed
that the starting point of the swing in
the animations (where the club head
was right behind the ball) and the ending point (where the club met the ball)
were often several inches apart. As the
ball doesn't move until it's struck, this
discrepancy is likely due to sensor drift.
The onscreen avatar is also a bit misleading, because its movements are just
a stock animation that has nothing to do
with what my body actually does. In this
sense, the video capture was more informative because it showed how my body
and the club moved together. But there
are numerous golf apps available that
do video capture alone for a few dollars.
Still, I found that the system was valuable for identifying what went wrong in a
less-than-ideal swing. Alas, such knowledge is only the first step to improvement. Although the app provides a library
of tips and a few video lessons, it can't
tell you why you tend to take too long of
a backswing, or how to break the habit.
Golf is perhaps uniquely suited to
data-based training aids: It's a quantitative sport, with success measured
in strokes, and there's always room for
improvement. But after a long session
of constantly replaying, analyzing, and
reliving each swing, it feels good to turn
off the screen and just hit some balls.

while back , i got a che ap wireless l acrosse
brand weather station, with sensors for temperature, humidity,
wind speed and direction, and rainfall. the stand-alone display
shows weather conditions using seven-segment LCD numerals.
the box the station came in promised that it "Connects to your pC!," which
appealed to me because I'd be able to automatically log the data and pass
it around my home network. Well, it turns out that this promise could be
honored only if I had a pC of the precise operating system and vintage
that the station's USb-to-wireless dongle called for. I'd also need just the
right version of some proprietary weather software. Unfortunately, my
Macintosh setup met none of these requirements. * Sure, if I had access
to an already working installation (and a lot of time), I might have tried
reverse engineering the embedded hardware and software. In theory,
I could have figured out what the weather-station components were tell-
ing the dongle, what the dongle was telling the pC, and what commands
might be flowing in the other direction. then, with some more work and
time, I could have reproduced that conversation on a Linux or oS X box.
but I didn't have the access or the time. * So I decided to make do with
the station's stand-alone display. I've been learning how to use openCV, the

-JoShUa J. roMero

ocT 2013

norTh aMerIcan

sPecTruM.Ieee.orG

left: swingtip; right: paul wallich

http://sPecTruM.Ieee.orG

Table of Contents for the Digital Edition of IEEE Spectrum October, 2013