Gadgets: Sensor tracks runners' strides

Polar's new Stride Sensor allows runners to collect information about their stride and then link this information to a phone app that calculates speed and distance data through GPS. It connects to the phone through Bluetooth Smart and is helpful for people trying to track calories or improve their running performance.

The Stride, which can be used in tandem with a heart rate monitor, sends signals to a Bluetooth Smart-equipped phone (later-model iPhones and Samsung Galaxys, according to the Bluetooth website). While you are running, it gives audible guidance, telling you when you reach a target distance or time, or burn a specific number of calories.

But before this can benefit the most serious runners, it needs some improvement. For maximum accuracy, the sensor must be calibrated on a one-mile course. No matter how many times it was set in one test, it remained inaccurate by the same tenth of a mile — enough of a margin to make the sensor nearly useless to a competitive athlete. A company spokesman said Polar was looking into the problem.

You may be familiar with the two-screen experience through TV, where viewers are encouraged to use a computer, phone or tablet during a show to see video extras.

IExit is an app that brings that two-screen experience to a car's GPS. People are distracted enough while driving. But this second screen may make it less distracting to use a GPS, and it's useful even when you don't need a GPS.

What iExit does is to show you what food, gas and lodging chains are at coming exits. You can also do this on most GPS units by setting it to show Points of Interest, or POIs. Or you can search "gas nearby" on Google.

The way the app works is simple. As you are driving along a highway, a list of services at coming exits scrolls down the iExit screen in icons and short names. Even when you don't need GPS directions, iExit may be handy for deciding where to pull over for a break.