i want to make a guitar tuner by self.i know the logic that the project needs,ie, accepting sound, filtering the frequency and then controlling LEDs through the filtered signal.please help me make it.i just want to accepts one frequency of 440 hz.

 

Got an iPhone? - http://iphone.wareseeker.com/tuner-440.app/42f286355d

 

find a frequency to voltage intergraded circuit and measure the output voltage when you have 440Hz input.
then put a comparator circuit. on the one input connect the output of the intergraded circuit and on the other input put the voltage that you find before with a voltage divider.
it should work.
if you need more help just email me. <snip>

 

sorry my friend i have a mistake on the circuit that i told you.
at the output of the comparator you should connect an LED but it will turn on when you have frequency equals to 440Hz or higher.
simpler you can just connect the output of the frequency to voltage intergraded circuit to an analog volt meter and to see the voltage on 440Hz, then mark this point and you will know every time when you play 440Hz. also you can mark the voltages on the other notes that you play. so you will have a guitar tuner for all the notes.

 

You do realize that 440Hz is the 'A' (fifth fret) above the open 1st string 'E'?

The open 'A' fifth string is two octaves down at 110 Hz.