In what could be seen as another indication that wearable tech is gradually becoming the focus of the future, Apple filed an interesting patent application for what it calls a 'Smart Shoe.'

The application describes a sensor and an alarm system that can be embedded into the footwear, helping users with notifications as to when they should replace worn-out shoes, the Apple Insider reported. The patent, first filed with the U.S. Patent and Trademark Office in July 2012, looks to cover a smart-shoe system with a shoe wear-out sensor, body-bar sensing system, unitless activity assessment and associated methods.

According to the company claims, the shoe can provide better stability for feet during physical activities such as sports or training in addition to comfort and protection. The Apple touch to the shoe comes when the footwear reaches its 'critical wear level' or a condition where the shoes' support decreases over time and continued use. The sensor and alarm system in the shoe is an apparent solution to protect users from suffering foot damage as it notifies them with the real condition of the shoe.

The Apple patent covers mainly three components such as a detector for sensing when the shoe wears out, a processor to measure the detector's data, and an alarm to notify the user when a shoe is no longer stable. Further details show that sensors can be of any kind including pressure sensors, accelerometers, and piezoelectric flexing sensors among many others. The algorithm to measure data can be configured according to manufacturer's specifications, which determines the point in which the shoe is deemed worn-out.

"In one embodiment, a 'unitless' activity number may be assigned to the sensed motions by the processor, which in turn generates an 'activity value' based on a predetermined maximum number. The unitless system can also be applied over time by taking samples at periodic intervals," the report said.

The body bar sensing component associated with the shoe measures the repeated movements of lifting weights, which can be processed and shown graphically on a display device. The shoe would be powered through a built-in battery or a mechanical electric generation device. The alarm system would be in the form of an LED light, speaker or display. A wireless interface embodied in the system enables compatibility with other portable iOS devices like the iPhone or iPad.