Activity meters are ideal for quickly counting the number of steps taken. The pedometer can easily be attached to a belt. You can also keep it in your pocket. Every step you take is registered with this. An activity meter or pedometer is also referred to as a pedometer.
A mobile phone nowadays also has a form of pedometer built in. These are only much less accurate. In addition, many people keep their mobile in a bag or leave it on the table so that no measurements are taken.