The Nike iPod Sport Kit in unsupported shoes
By drapeau on Aug 06, 2006
I got an iPod nano recently, to replace my third dead iPod Shuffle (watch this space for a rant on my woes with the iPod Shuffle). Since running is my primary form of exercise, I decided to spend the extra thirty bucks or so and buy the Nike iPod Sport Kit, a device that lets you use your nano to track your running (or walking) workouts. It uses a sensor that you put into your shoe, which transmits data to a device you plug into the nano. Here's the catch: the sensor is pretty sensitive about where it needs to go (into the midsole of your shoe), and there are only a few Nike shoes that have the proper hole in their midsoles that can fit the sensor. I don't have any of thoes shoes. Here's what I did to make it work with my non-Nike-supported shoes.
Here's What Not To Do
The first thing I tried was to place the sensor between the laces of my shoe and the tongue, as far forward as it would fit. If you were looking at the shoe from above, the sensor would be visible, looking as if it were lashed to the shoe. That didn't work at all; no motion was detected whatsoever. Apparently the accelerometer in the device needs to have some pressure on it to help determine your footstrike; here in Nike/Apple's FAQ about the device.
Next, I tried placing the sensor between the side of my ankle and the shoe, sort of on the side of my Achilles tendon. That seemed to work better, but it wasn't terribly stable (it jostled some) and I don't think it made for very accurate measurements.
Here's What Worked
Finally, I decided to carve my own divot out of the insole of the shoe. Turns out that really isn't necessary to make the sensor work, but if you can carve a little divot into your insole, it'll help. Otherwise, it feels a little bit like you're running with a pebble under the arch of your foot.
|Step 1: Remove sole insert,
optionally carve hole for the sensor. I used an Xacto knife to
carve this hole, which wasn't very deep (I hit the hard part of the
sole and didn't want to cut into that for fear of ruining the ride of
the shoe). Turns out this step didn't do me much good; I don't
recommend it unless you're bolder than I am and are willing to cut
deeper than the soft tissue of your shoe's midsole.
|Step 2: Place the sensor
in the midsole, directly under the highest point of your foot's arch.
|Step 3: Tape the sensor to the
midsole to keep it stable. When the sensor was placed here and
held in place by the tape, it worked perfectly. This must be the
proper place for it to optimally determine your foot stride. When
I compared the distance reported by the sensor vs. my Garmin Forerunner
GPS unit, they matched well. I also ran around a 400-meter track
and the sensor was right on target.
Once Again, Duct Tape Is Our Hero
Well okay, it was electrical tape in my case, but you get the point. I'll probably buy a pair of Nike shoes that has the divot already made, because it's deep enough to fit the sensor in it all the way. The way I did it here, I could feel the sensor during the entire run. It wasn't too bad, not enough to really bother me or make a bruise on my arch; nothing like that. But I'd like it better if I felt nothing at all, and I can't find a better place for the sensor so that it works correctly. If anybody else has a better idea, I'd love to hear it.