About Whistle Key Chain Finder Circuit - A Friend's Suggestion

Hi Swagatam,

After a little gap I am e-mailing you again.

This time I do not need any clarification on any of your projects. Rather, I have an idea which I would like to share with you.



First let me inform you clearly that the idea of making a home made circuit came in my mind from a small gift which was presented to one of my relatives by one of his old mates. Now, you may be wondering what is the "gift" I am talking about. Well, it is nothing but a Chinese made "Whistle keychain finder" (please refer to the attachment).

The beauty of the product is that when it is switched on, it will only respond (a chime would start playing for a brief moment) to a whistle which we make from our mouth and NOT to any other sounds eg., if we blow a whistle or a flute etc. 

Therefore, I would like to know from you, if this idea/concept can be used to construct a home based  circuit project with the same feature and maintaining it's compactness in size, battery life and last but not the least keeping in mind the COST to be as low as possible. It can be a very useful project for our day to day life. 

Waiting anxiously to hear from you soon.
Thank you,

Kind regards,

Raj




Hi Raj,

Thanks for the nice suggestion. These key chain devices are indeed amazing, I wonder how these are able to recognize and distinguish human whistle signals only. 

However making such devices at home would be impossible because they involve hi-tech programmed circuitry and are in the form of microchips, not feasible at our level.

But yes, we can surely modify such devices as per our specs, just as we did with FM radio and transmitter circuit.

The output from this device can be amplified and used for operating electrical appliances etc. through relay.

The appliances would then respond to our whistles and operate accordingly.

Thanks and Regards.

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