hc-sr04 ultrasonic sensor

[asim_123]

hi friends i am workingon hc- sr04 ultrasonic sensor i am getting constant voltage on echo pin if obstacle place infront of sensor that a problem the voltage are not changing ... i am using atmel 8051 microcontroller....

 

[klystron]

Please post a diagram

 

[chuckey]

data sheet : - **broken link removed** it sats that you have to pulse it to transmit and you get a pulse back that is reflected. have you checked with a CRO for the return pulse?
Frank

 

[asim_123]

no i am checking the echo voltage that is not varying it give contant voltage