our project title is " digital hearing aid" .
Simply, it receives audio signal then make some processing on it (e.g. filter ) and finally output amplified version of the input signal. recently, a lot of features can be added to the above simple design. we need any assistance?
Regards
we need any assistance?
Do you?
Simply, it receives audio signal
What does? From where?
You realize that the Arduino is not particularly well suited to audio processing (that pesky negative voltage, for one thing). Not to mention which it is, in general, far too slow.
then make some processing on it
Random processing? The Arduino is not a good digital signal processor.
and finally output amplified version of the input signal.
Output it to what?
a lot of features can be added to the above simple design.
What design? All I see is some handwaving.
All I see is some handwaving.
Perhaps it is a hearing aid for digits. 
might be add on function of Google Glass;-
mic pick up voice then voice recognition to display on glass, drop a line to google ask them add on.
Using Google Glasses voice recognition the ‘weirdest thing