Distance measure with ultrasonic

Projects General Guidance
1

Dear sir,

I am trying to measure a distance and tell the distance in voice by using ultrasonic sensor. But when an obstacle detect below 100 cm (as i programmed ) the output is stable but when the distance is above 100 cm or there is no obstacle in front the ultrasonic sensor then there is unstable output.It's gives random false output just like 35,77,102,89,25,14 cm etc.I need a stable output which is mandatory to my project.

2

Try a different sensor. Some respond up to 4 meters, and have a timeout for the case that there is no object to reflect the ping.