# Distance Measurement, by ultrasound echo

Objective

Measure distance by measuring the time taken by pulse train to echo from a hard surface.

Procedure

- Keep a flat surface, like a cardboard sheet, around 10 cm from the echo module

- Press START

- Change the distance with time

Discussion

The distance is calculated from the time taken by a burst of sound to echo from the surface kept in front of the module. The distance can be measred as function of time, enabling to calculate velocity, acceleration etc.