How does a pedometer work?

Answer

Dear Show,

a modern pedometer, such as present in a smartphone, works by processing the signals from a combination of sensors. The processing of the signal and is done in software.

The number and type of sensors used depends on the complexity of the pedometer. The sensor necessary to count the number of steps is a 3-way accelerometer (https://www.st.com/en/mems-and-sensors/accelerometers.html). These are small components that can measure accelerations in 3 dimensions. The combination of the measured accelerations in the 3 dimensions is used by the software to determine whether or not you are walking and how many steps you are taking.
In combination with the accelerometer, additional sensors are often used to more accurately determine the movement and to rule out that you are, for example, simply swinging the pedometer. The following sensors are sometimes integrated.

• a gyroscope (https://www.st.com/en/mems-and-sensors/gyroscopes.html) to measure rotational motion, for example of your torso when walking
• altimeter (https://www.st.com/en/mems-and-sensors/pressure-sensors.html) to measure whether you are climbing or taking stairs
• compass (or magnetometer) (https://www.st.com/en/mems-and-sensors/e-compasses.html) to determine the direction change.

I hope this helps you further.

Regards.