Here is smart sensor that lets you monitor your indoor and outdoor cycling workouts on your phone. The SunnyFit CB100 Cadence / RPM + Speed Sensor syncs to your phone or tablet via ANT+ and Bluetooth. To install it, you simply have to place it on the rubberized mat and wrap it around your bike’s crank with the included bands.
The companion app gives you access to hundreds of lessons. You can also use it to view and track your data in real-time.