Quick, how many different types of bike component can you get with a built-in power meter? We make it five (cranks, rear hub, bottom bracket, pedals, and cleats). And now six, if you count the power meter shoes just announced by Spanish shoemaker Luck.

Luck says its power meter shoes will have a sensor in each shoe, located below the foot's metatarsus — just above the cleat mounting area, in other words.

The sensors will collect information about power and cadence from each leg each leg and use Bluetooth to transmit it to a mobile phone in real time. Luck says it will be compatible with Android and iPhone, by which we take it to mean there'll be a matching app for each platform.

The sensors will have rechargeable batteries and will be interchangeable between shoes, so if your shoes wear out or get damaged in a crash, you can move them to new shoes.

The sensor and electronics shown in these pics are prototypes, says Luck, with lots of details still to be finalised. The production version will be very light and compact, the company says, and practically imperceptible to the rider.

Luck's power meter shoes are still some way from production, so don't get too excited just yet. The company says it's hoping for Christmas 2014 availability, but the history of power meters outside the main bike transmission is one of long delays.