Posted by: jinoe | July 28, 2008

Nike+ Sensor Dissected

When I first saw the Nike+ Gear I was amazed by the product and the technology. Being an engineer, my first question was:  How did they do that? How was the sensor able to pick up the signals from the shoe and transmit it to the iPod? How does it calculate the pace and distance of the runner. I thought it was GPS. But the price is too small for a GPS technology.

I didn’t have a Nike+ Gear. I prefer another brand of shoe. But thanks to fellow curious runners and engineers who decided to open it up and look inside the sensor. Maybe if I can do a reverse engineering on the gadget, I can create my own sensor for my own shoe and be able to join the Nike+ Human Race.

There are several sites that explains how the sensor works.

1. The heart of the sensor is a piezoelectric accelorometer. Ah what? Piezoelectric materials have (1) the ability to produce current when they change shape, or (2) they change shape when exposed to electric currents. A good example of property 2 is a piezoelectric tranducer used in speakers or buzzers.  You press the switch, it sends current to the piezoelectric buzzer, and the rapid change in shape creates the buzzing sound. The round thing on the right is the piezoelectric accelerometer. Below it is the battery.  The black chip on the left is the transmitter that send the data to the iPod Receiver.  Hey!  I don’t see any of our company products here.  Tsk tsk…

Nike+ Sensor Dissected

Nike+ Sensor Dissected

Got this picture from Flickr. The sensor was dead after 111 runs, 575.66 Km and one year and 2 months. Thus the owner decided to open it up. Neat!

2. Piezoelectric sensors uses property 1. It’s sensitive and fairly accurate. Every time there is a change in the shape, it produces an electrical current that can be converted to useful data. This is the same property found in a Wii controller. It wont be long until you get a spoon that tracks how many times you’ve served yourself with a meal. Hey! Maybe I should file a patent for the spoon idea.

3. The accelerometer detects if the person’s foot is on the ground. The pressure when the shoe is in contact with the ground will change the shape of the sensor and will produce electric current. This current will then be detected by other sensors and by a processor that converts it to the data runners will use.

4. To get the speed, it monitors how long the shoe is in contact with the ground. The shorter the contact, the faster the speed. The distance can be then calculated by using a clock to get the time spent for running.

Interesting gadget. Since I don’t own a Nike+ shoes nor a Nike+ gadget, can I now do some reverse engineering and a DIY sensor? Hmm… I might not be able to run anymore trying to figure it out.  But I really want to use the sensor without both the Nike+ shoes and the iPod.  That will be some hardcore hacking.

Anyway, there are also runners who have tried several ways to use the sensor with non-Nike+ shoes. Very creative results.  Read some of them here.

FitMommy had her own DIY for a Nike+ hack. Yan ang wais!

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Responses

  1. Nice idea on the spoon!

    A good project, noh? Mapag-umpisahan nga… 😀

  2. The best hack I read about used a condom (unused I hope!) tied to the shoelaces. I didn’t try it out though, I just bought the marware pouch from imac.

    I read that too but decided not to include it in the list of hacks I mentioned at takbo.ph. I would rather use it to where it was best intended… for water balloons. Hehehe.

  3. Mommy na kasi ako eh 🙂 Mahilig pang mag-tahi… Was supposed to buy marware too. But I NEEDED a pouch ASAP. So, after looking around in the internet – decided to make one ma-self!

    Ako kasi wla pang iPod e. I preferred a different mp3 player. If I had one, I’d make a DIY as well.

  4. I used the switchpod. P800 from istudio a couple of years ago.

    Hi TBR. At P800, that seems like a good deal already.

  5. Hey, I used this instructable to fix mine after it died. It’s been working great so far, and it didn’t take very long.

    http://www.instructables.com/id/Replace-battery-in-Nike-receiver-for-under-5/

    Hope this helps!


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