how to make baby crying detection circuit

Hey guys,

I want to make a simple baby crying detection circuit. I have an electret microphone and a speaker of 8 ohms and 0.5 Watts and arduino uno micro-controller. Can anyone tell me the steps needed in making a simple baby cry detection circuit. I want the microphone to take the sound and use micro controller to detect if the sound is babys voice, if so ON the speaker and output the voice. Can anyone give me the steps needed to make it happen and point me to simple circuits.

Thanks.

Dear scream_er
Hi
You will have two way . first way is very complicated with DSP ( recording the voice of Baby and comparison between that and the voice of ambient with DSP) !
And the 2nd way is really simple but it has some tolerance : use from a simple peak detector with op amp and use from a simple microphone near your baby and comparison between that and a DC voltage (low amplitude) ( with simple opamp ) !
Best Wishes
Goldsmith

Thanks, can you explain abit more about the second way?

Dear scream_er
Hi
Sure. Remember : if you use an op amp as a simple comparator ( without feed back) if the v+ be higher than v- , the out put will be about +vcc . and if the v- be higher than v+ , the out put will be about -vcc . you can use a simple capacitance microphone , near your baby , and give the out put signal of that , to the voltage amplifier , and then give it to your op amp( its v+) and give a variable dc voltage to the v- of that (with potentiometer , to have calibration as well as ) . if the microphone get the sound of baby ( when you are not near your baby ) the v+ will be higher than v- and the out put will be about +vcc , and then you can excite the base of BJT to give command to the relay , and then the relay can turn on the alarm system!
Best Wishes
Goldsmith

I want to amplify the voltage from electret microphone to atleast 1V. The output from the electret microphone is just few hundred uV. I have 2 circuits as attached, which one will be the easiest and can do the job for me. I have 3 options, but what is the best option?

1) should i use lm358n as in the 1st attachment or
2) use dual lm358n for higher gain or
3) use lm386n since it is simpler.

LM 358N


LM 386N

Please read my reply in the other thread.

scream_er you have shared some pictures of op amp circuitry can you please help me in finding its equation...

i am week at developing equations and understanding circuitry ......

@ mrarslanahmed, i myself isnt that good either. Im a novice like you, but I found Operational Amplifier Tutorial - Op-amp Basics quite helpful.