what are sonars?? i mean are they only ultrasonic sensors or more??

[Faiza93]

hey, i am new to sonars infact i don't have any idea how do they work.. i was thinking of using them in security systems as it scans the area.. but how does it show its result?? i mean does it has a buzzer or something if it detects any motion?? please help.. and yes is sonar simply an ultasonic sensor or something more??

 

[betwixt]

It's the audible frequency equivalent of RADAR. SONAR isn't a device or product, it's a technology. The basic principle is to pulse an audible or ultrasonic burst of sound through a transmitter and listen to it on a receiver. The receiver will pick up the transmitted sound and also reflections (echoes) from nearby objects. The simplest detectors do nothing more than monitor for changes in the received signal level which would indicate a change in the path the signal travelled through. On seeing a change they operate an alarm of your choosing.

More complicated systems use several receivers and monitor not only levels but phase/frequency shifts (Doppler shift) and can tell where a moving object is and which direction it is travelling in. These are complicated devices though and certainly beyond 'hobby' levels of construction.

Brian.

 

[Faiza93]

thank you Brian, this is really helpful!!