Hi!,

i want to know on this circuit on how far the signal will travel?

 

Hello,

Here is a link to see how the senitivity and directional properties can be found.
http://www.cs.brown.edu/~tld/courses/cs148/02/sonar.html

It comes from this page: http://www.educypedia.be/electronics/sensorsultra.htm

Greetings,
Bertus

 

There are too many unknown variables to predict the effective range of the circuit in this case. It depends on the transducers, the way they are mounted, environment, target size and composition etc. etc.......

Can you give an example of the application?

 

Don't use a standard 555, it will fry the transistors.

 

is this ultrasonic sensor range meter circuit?

 

No. It is a simple proximity detector.

 

Published in Popular Electronics, I was impressed. It uses doppler U/S to detect movement, but is an extremely simple design. Basically a U/S AM reciever, if it detects low frequencies it is caused by something moving in the oscillator field of sound.

 

The circuit looks pretty old. It uses a lousy old LM324 quad opamp that barely amplifies frequencies as high as ultrasonic. It can't even amplify ordinary audio frequencies.

The range is determined by the thickness and coverage of the burglar's clothes.

 

Published in Popular Electronics, I was impressed. It uses doppler U/S to detect movement, but is an extremely simple design. Basically a U/S AM reciever, if it detects low frequencies it is caused by something moving in the oscillator field of sound.

How did you deduce that it is a motion detector? I don't see any Doppler detection circuitry. It looks like a presence detector to me.

 

Its receiver has an AM detector. Anything that changes the amplitude of reflections will produce a level change which is AM and it will be detected if the sender and receiver are close enough together since the lousy old LM324 opamp is so bad.

 

It's just an amplifier, a slow half wave rectifier, and a comparator. The gain is fixed. The comparator threshold is manually adjustable. If the input level is below the threshold set by VR2, the LED is off. If the input is above the threshold, the LED is on. Assuming the LED is off when there is no motion, the only change in amplitude it will detect is an increase. If the amplitude decreases, it will not be detected. If you want to call that an AM detector, well, OK, but there is no Doppler detection.