Is It Possible for a Sensor to Detect Only Continuous Sound?

How about a microphone? What exactly are you trying to do?

i want to detect a emergency vehicles sound.. i think so it is differing from other sounds that it is continous and other sounds are discrete.. so i need a sensor to detect only continous sound. i dint need microphone...

It is possible, but probably more easily accomplished in signal processing rather than in the sensor itself.

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If you are dead set in doing it with the sensor, one way to do it would be to build something like a tuning fork that resonates at a frequency found in your ambulance sound, and then measure for deflection over a minimum threshold.

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It shouldn't be too hard to adjust it such that an indication occurs when the fork is subject to one of a set of frequencies for a sufficient period to cause enough deflection.

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But using a microphone and then working with the signal is probably much easier reliable and straight forward.

how can i work with microphone??? is it possible to detect only emergency vehicles sound using microphone??

If you know the pitch (note) of the sound you are trying to detect, it should be possible to construct a cluster of pipes tuned to that note. You could then set this cluster of pipes in front of the microphone and the microphone will then primarily respond to that note. Here's a link to the physics of open-ended air columns:

http://www.physicsclassroom.com/class/sound/u11l5c.cfm

Just buy a scanner and listen for the radio calls while you are inside the bank.

Too many false alarms your way.

This may not be that practical at first glance as the sound source will be moving and you likely also need to take into account the Doppler effect.

Sound capture and processing using digital signal analysis (either using a computer or microcontroller) is likely the best way, but a simpler cheaper way may be to just detect key frequencies present in the sound you are trying to detect (but this increases the chances of false detections).

Regardless it is quite complicated. What is the application?

"It is possible for a sensor only to detect continous sound? (like ambulance sound)..."

Yup, I use them all the time.

A siren sensor. A common use for this is at an auto gate. An emergency vehicle will sound its siren and the gate will open, allowing entrance. Will not respond to a car horn.

Is this what you are after?

The link's broken. it is actually www.sosgate.com

This looks promising sarav07k however please be aware that in different countries emergency vehicles may not use the same siren sound and so this product may not work in your country.

It will however give you an idea about what is possible, but again it is a standard sensor connected up to a microprocessor which analyses the sound to detect the particular sound of an emergency vehicle siren.

Huh... the link works for me. Dunno...

Your observation is valid, and is certainly a point to discuss with a vendor familiar with sarav07k's local emergency response vehicles.