# Distance Measurement, Echo module

Distance can be measured by sending a burst of sound to the target and measuring the time interval to receive the echo. There are low cost electronics modules available for such applications. Hy-SR04 is such a module, that uses a 40kHz Piezo transmitter and receiver combination.

# Objective

Measure distance by measuring the time taken by 40 kHz pulse train to echo from a hard surface, using HY-SR04

# Procedure

- Make the connections as shown in the schematic
- Keep a flat surface around 10 cm from the SR04 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 measured as function of time, enabling to calculate velocity, acceleration etc.