How does Pedometer Android application record or count steps?

Pedometers app works on devices with built in accelerometer sensor. When you start running or walking this app starts monitoring the changes in accelerometer and decide that step is taken or not. This is how it works offline. Some Step Counter app works with GPS. This app have calaculates data based on distance and time.

For Example : If you cover distance of 1 KM in 10 , you are walking at 6KM/per hour speed. So inbuilt will show you how many calories you have burnt or how many steps you have walked.

Early Pedometer works on due to mechanical sensor and software to counts steps. They have pendulum which counts on each back and forth while swinging. Thus calculating the total steps taken by the person.

Modern Pedometer works on similar way but have electronic pulse.