Initial testing of the cadence sensor with the hard disk magnet affixed to the back side of the crank seems to yield the desired result!
Here’s a better look at the magnet:
So after a few trips down the rail trail and back I decided that I didn’t really want to trust A-GPS from my iPhone 5S to deliver accurate speed and distance information to Cyclemeter. After all, if I’m going to ride forty-odd miles and then analyze the ride data later, shouldn’t it be accurate? So I needed a speed sensor.
Cyclemeter is compatible with a wide range of devices. Given my application, I decided to pick up a Blue SC from Wahoo Fitness. This tracker will not only do speed, but also cadence. Initially cadence wasn’t important to me, but after reviewing ride data for a few short runs, I’ve found it to be useful in improving my pace in a few spots that have rough asphalt or hills.
The Wahoo Blue SC includes the main unit, a magnet to attach to a spoke for the speed sensor, and a magnet that slips onto the crank to measure cadence.The devices look something like this when installed: Here it is on my bike: