HC-Sr04 query

Other Hardware Sensors
1

Hi ,
When does the echo pin become high in the ultrasonic sensor (HC -SR04) ??
i had set the sensor to light an LED only when the distance of the object is less than 10 cm. it works wonderfully well . But, now the doubt is whether the echo pin is HIGH for all the distances of the object or only when the object is less than 10 cm ???

2

???
The sensor ouputs HIGH while receiving the 8 pulses it emits... with a tiny delay.
There is a datasheet to be found on net where thr theori is explained.

3

thanks