I am working on another project at the moment. My wife is very pregnant, and I thought it would be cool to be able to hear our babies heart beat at our leasure, make recordings, etc. I put together a circuit, involving an IC TLC272 to pre-amp the mic, and IC LM386 to amp the head phones. My gain is set to about 90, using a 4.7µF cap across pins 1 and 8. I will be powering this by a 9v battery, or perhaps a wall wart if I need the additional power.
Both IC's are going to be controlled by pots, probably around 100k, until I know exactly what I need to aquire these sounds. I will draw up a schem tonight and post it, and hopefully get some good suggestions for making this work.
My current circuit works, but doesn't really pick up those ultra low(quiet) sounds. My mic is brand new, but I may need to put a cone around it to act as a sound collector, but then you easily risk outside noise distortion.
Adam
Both IC's are going to be controlled by pots, probably around 100k, until I know exactly what I need to aquire these sounds. I will draw up a schem tonight and post it, and hopefully get some good suggestions for making this work.
My current circuit works, but doesn't really pick up those ultra low(quiet) sounds. My mic is brand new, but I may need to put a cone around it to act as a sound collector, but then you easily risk outside noise distortion.
Adam