Sound recognition desktop fan

[FrozenTear]

hi all, i'm working on a project call sound recognition desktop fan. These are the circuits that i designed out. The 1st circuit is having higher sensitivity, which means it can detect any sound from the environment, but my project is to use hand clapping sound to trigger the fan to on. So i designed out another circuit to lower the sensitivity and it works. Can anyone please explain to me the theories behind these 2 circuits? Is there any theory or calculation that can explain the changes that i made in these 2 circuits? I have circled out the changes that i made.
https://obrazki.elektroda.pl/89_1293083812.jpg (higher sensitivity circuit)
https://obrazki.elektroda.pl/85_1293084480.jpg (lower sensitivity circuit)

 

[krishna1234]

you just increased the impedance level to the second transistor input there by only high amplitude voice can drives the transistor to higher level.so the circuit respond only to higher voice like clap.

 

[phillipcrosby]

I have a similar problem but want to focus on a starter pistol retort not clapping. I have build a single clap kit MK-139 that works on one clap but need to modify it to respond only to starter pistol not clap. I assume that I need to push to have the circuit recognize only the biggest spike in sound. I need help in deciding how to do this using theis simple starter circuit. I also want to improve the relay action to reduce the delay in engaging the relay which is now 1.05 seconds on average. I need just a simple momentary switch action from the circuit to trigger my computer program through a mouse command.

 

[router99]

Hi,

This is a very good application. I have used colea software for speech processing for my
ceiling fan.
Pls get the ref. materials and go through it. In that you will find frequency spectrum representation and related to speech processing.

It may help u.

Thanks..