Apple applies for shoe-life sensor patent, puts it in hypothetical brogues@ 2013/01/25
The application draws together two possible outcomes: one with an thin sensor layer built your footwear of choice and another which keeps the sensor in the heel. A "unitless activity number" is also mentioned, where the device (which could include accelerometers, flexibility sensors and more) could craft an "activity value" based on your movement -- this would then also be used to gauge the shelf-life of your current footwear. When this pre-specified threshold is exceeded, it would then sound the alarm. According to one diagram, the process could connect with an external display, likely broadcasting its concern to your nearby iOS device. But if your running needs demand a sensor to tell you when your sneakers are cooked, there might be other things worth tracking.