Sound activated switch/timer

[nandgate]

i would like a circuit diagram and materials list for a project that would pick up a sound via condensor mic and filter it for a certain frequency range (10KHz~15KHz) and strength (80db). This frequency and db must be used to activate a timer and switch for a period of say 90 seconds to take control of the circuit and then return control to the main controlling device. All help will be greatly appreciated. Thanks.

 

[kinjalgp]

You' require a clap activated switch long with a monostabe multivibrator with on time of 90 seonds which is triggered by the clap switch.
You can find schematic of clap switch at:


And for monostable search in google.

 

[bogdanfirst]

why not a 555?it works fine....
but you need to adjust the clap circuit, beacuse when you clap your hands you dont generate 10KHz....!!!!!
maybe it will not work...
i think of something like an amp, a filter and trigger....and of course the 555 monostable

 

[kinjalgp]

Even I was talking about monostable based on 555.