Kickstarter funded Digitsole showed off their smart insoles at CES 2015. Via your smartphone you can set the temperature for comfortable feet even on cold winter days. In addition the sole can detect foot steps, distance covered, and combining this with weight and height measurements, can make a coarse estimate of the calories used. To control the insole and get feedback on your activity an Android or iOS app is used, via bluetooth.
Depending on how warm you like your feet, 6 – 9 hours of continuous use is expected. Charging is via a micro USB connector in the heel of the insole. The product is available now at a price of around $200 or Euro 150
The layered construction of the insole is illustrated here.
Source: CNET