Simple Voice Pitch Detector?

[girl_genius]

Hi everyone, new member here. I teach voice on the side and would be interested in making a little device which could detect the pitch (frequency) of a human speaking or singing voice. Either with a digital display of the pitch in KHz or even better, to keep it simple for my students, a light comes on when the pitch is between 175-220 KHz. Any ideas on kits or schematics for this? I searched the forum before asking, and saw some similar ideas but nothing close enough.
I saw a kit with digital readout like this here: http://www.apogeekits.com/frequency_counter.htm, but would prefer something cheaper or simpler like the "light on for frequency between a certain range" idea.
I appreciate your time, wisdom and responses. =)

 

[Alun]

Htis kit would work but you only need audio frequencies (20Hz to 20kHz) this kit will work from 15Hz to 8MHz, you could always use a PC with a sound card and some special software as a frequency counter:
http://www.techmind.org/audio/#mustun
http://www.handyarchive.com/free/frequency/

 

[MP1]

I know you said 175 to 220 KHZ...but I am sure you meant 175 to 220 HZ.

Since you are looking for an audio range, and more importantly, only need 175 to 220 Hz, you might search for a guitar tuner circuit. Many of these will allow guitar cable input and meter or light to tell you when you have the correct tone. Your version would use a microphone and would only need a more narrow range of notes.

MP