To hell with that!
There are many options out there that will help get around buying Nike's special shoes, but for those of us who run outdoors, and run long distances, we just don't feel safe mounting it above the shoe (at least I don't). So why not just model my current running shoes after Nike's special shoes?
NOTE: This Instructable involves cutting a hole in your shoes. I am not responsible for any damaged shoes, injured legs, cut fingers, or broken Nike+ kits. '
All of the instructions are detailing how I did this, how you should do this depends on your shoe, shoe size, and preferences, but it should be mostly the same (just different measurements involving sensor placement)
Step 1: Tools/Hardware Needed:
Foam Core/Mat Board X-Acto Blade (optional, but helpful)
Step 2: Measuring
My measurements are (you should measure your own to double check my measurement):
1 3/8" x 15/16" x 1/4"
Step 3: More Measuring
With my foot I had about 1- 1/2" in depth of area that my arch was raised. Obviously while running this will change, but this seems like one of the best spots for minimal pressure and stress.
Step 4: Placement Ideas
Step 5: More Measuring, More Cutting
I cut a strip of paper out at this size to fit into the shoe, because I don't have any rulers that will fit inside of my shoe. After placing the strip inside my shoe I marked the first corner.
Step 6: How Much More Measuring?!
The dimensions for the sensor are 1-3/8" x 15/16" (ignoring depth for now).
For my shoe, the easiest way of tracing it on was using a thick pen (.8mm).
For those of you not happy about having to write on your shoes, consider that in a few moments you'll take a Dremel and X-acto to them, and that the pen should be the least of your worries.
Step 7: Cutting!
What I did here was take a foam-core x-acto blade and set the blade out to 1/4" (depth of the sensor). I went inside of the shoe and scored across the midpoints of the square to determine the depth.
Step 8: Now the Fun Part
That didn't work well though, granted it got a lot of pieces out, but it was choppy and difficult (cutting through rubber).
So using my Dremel with sanding bit I went in and sanded out the whole.
Keep in mind here you are NOT cutting out the entire square drawn, but just an oval shape that fits within it. Do NOT cut a square. Seriously, you'll ruin your shoes (more so)
As far as the curves of the sensor went, it was more a matter of estimating. Someone with extra time could probably go and measure the radius's, but for me it was more a matter of starting smaller, and testing by trying to put the sensor in.
The cut marks made earlier (optional step) are nice because they'll give a rough estimation how far you should sand down. Also they help to ensure that the hole is flat at the bottom. If you didn't do that step, you could probably just do it carefully by checking the depth very often.
Step 9: Placement/Finished!
Clean out the dust, and make sure the sensor fits snug. It should not move around within it's hole or you'll get inaccurate readings. Place the removable sole over the sensor and you're set.
Nike does recommend taking the sensor out when you're not running to save on battery life. For someone like myself who runs a lot, these are strictly running shoes, so I don't have to worry about that. I can't say what the shoe would feel like without the sensor in place, so if you plan on removing it you may have to mod a small piece of rubber to fit in the hole.
Step 10: Results/Testing
At 3 miles (according to the Nike+) I ran 20:07
Using Gmap-Pedometer, I checked my distance and got 2.9873 miles.
About 1/100 of a mile difference. I'm impressed!