輕鬆跑

一直很疑惑 NIKE+ Sportband 到底是什麼原理運作？

之前猜是震盪器隨著步伐前進去記錄後來查了資料

是 『壓電式加速規原理』---piezoelectric accelerometer

『...The Nike+ kit consists of two pieces: 1 - a piezoelectric accelerometer – transmitter – which is mounted under the inner sole of the shoe; 2 - a receiver that connects to the iPod. Nike recommends that the shoe be a Nike+ model as these models sport a special pocket in which to place the device. Nike sells the accelerometer individually, meaning that consumers do not have to purchase the whole set....』

文中提到的 piezoelectric accelerometer

看來是用到牛頓定律 F=ma 公式推出加速度值再轉為速度

及距離，這也可以解釋為什麼沒把傳送器放到NIKE+專用鞋的鞋底

會產生接受訊息上的誤差因為鞋底傳導的力量最直接也較準確

至於測的精確度如何就不得而知了？也許研究微機電這塊的專業人

士能夠解釋。

This force causes a charge to be generated and due to Newton law F=ma this force is in turn proportional to acceleration. The charge output is either is converted to a low impedance voltage output by the use of integral electronics (example: in an IEPE accelerometer) or made available as a charge output (Pico-coulombs /g) in a charge output piezo-electric accelerometer