This cct is some sound-activated switch without any filter. The first stage with op-amp is a mic-preamp, the second is an pulse former with 555, and the last stage is a counter.
I'm sure, You can find a better cct.
This cct is some sound-activated switch without any filter. The first stage with op-amp is a mic-preamp, the second is an pulse former with 555, and the last stage is a counter.
I'm sure, You can find a better cct.