user28257: I'm looking to recognize a particular sound using arduino uno.
I need to recognize a clap sequence to trigger a relay.
Having given it some thought i need it to be continuous listening mode with out any trigger such as a button press. The background will be quiet.
Is the arduino uno powerful enough to do this and how will i get stated on this? Any help is appreciated.
Note i need to do this entirely onthe Uno itself and not on PC like How do I listen for a sound that matches a pre-recorded sound? 
I am thinking i will prerecord the sound and compare with a live sample, is this feasible?

user28260: If it's just a clap sound and the background is quiet, then really all you'd need is to sense how loud the sound is.  This can be done using an analog comparator interrupt (this is present on the chip itself but not on the Arduino library).  If all the uno is doing is measuring the sound and maybe setting an output pin when it's loud, then just poll the analogs attached to your microphone and trigger the condition when the output is loud enough.  You'd probably need to amplify the microphone if you haven't already, but yes, the uno can handle that.
Edit: if it's a clapping sequence, then it can still do it.  Again, just measure the time between loud and quiet, don't worry about what the sound is (that is, you don't need to worry about exactly recording and analyzing the sound, you just need to know when it's loud and when it's quiet)

user27557: Adding to Michaels answer above which only works for some cases (and  it wont work perfectly even with a sequence of claps). To make it work in more cases you would need to store more information about the clap noise- as Michael points out in his comment above "properly identify" the clap- to make the identification more accurate. There are various ways to do this- you could compare it with live recording as you wrote in your question. I suggest tyou try neural networks to do such a comparision I. I would say you would need a two layer neural network with say a sample of different claps for training it-(its probably quicker to train it not with arduino). 
Here is a library for neural networks for arduino 
http://robotics.hobbizine.com/arduinoann.html
that you may use. Or you can implement you own neural network. Its well known that sound recognition can be used to analyse sounds.
The built in ADC of Arduino can probably be used to  record and good enough for something like a clap in your case-though it cant be used for high quality sound recordings.

28257: <p>I'm looking to recognize a particular sound using arduino uno.</p>

<p>I need to recognize a clap sequence to trigger a relay.</p>

<p>Having given it some thought i need it to be continuous listening mode with out any trigger such as a button press. The background will be quiet.</p>

<p>Is the arduino uno powerful enough to do this and how will i get stated on this? Any help is appreciated.</p>

<p>Note i need to do this entirely onthe Uno itself and not on PC like <a href="https://arduino.stackexchange.com/questions/8781/how-do-i-listen-for-a-sound-that-matches-a-pre-recorded-sound">How do I listen for a sound that matches a pre-recorded sound?</a> </p>

<p>I am thinking i will prerecord the sound and compare with a live sample, is this feasible?</p>
 28260: <p>If it's just a clap sound and the background is quiet, then really all you'd need is to sense how loud the sound is.  This can be done using an analog comparator interrupt (this is present on the chip itself but not on the Arduino library).  If all the uno is doing is measuring the sound and maybe setting an output pin when it's loud, then just poll the analogs attached to your microphone and trigger the condition when the output is loud enough.  You'd probably need to amplify the microphone if you haven't already, but yes, the uno can handle that.</p>

<p>Edit: if it's a clapping <em>sequence</em>, then it can still do it.  Again, just measure the time between loud and quiet, don't worry about what the sound is (that is, you don't need to worry about exactly recording and analyzing the sound, you just need to know when it's loud and when it's quiet)</p>
 27557: <p>Adding to Michaels answer above which only works for some cases (and  it wont work perfectly even with a sequence of claps). To make it work in more cases you would need to store more information about the clap noise- as Michael points out in his comment above "properly identify" the clap- to make the identification more accurate. There are various ways to do this- you could compare it with live recording as you wrote in your question. I suggest tyou try neural networks to do such a comparision I. I would say you would need a two layer neural network with say a sample of different claps for training it-(its probably quicker to train it not with arduino). 
Here is a library for neural networks for arduino </p>

<p><a href="http://robotics.hobbizine.com/arduinoann.html" rel="nofollow noreferrer">http://robotics.hobbizine.com/arduinoann.html</a></p>

<p>that you may use. Or you can implement you own neural network. Its well known that sound recognition can be used to analyse sounds.</p>

<p>The built in ADC of Arduino can probably be used to  record and good enough for something like a clap in your case-though it cant be used for high quality sound recordings.</p>
