I would like to build electronic units to detect termites
in the wood of a building via the sounds they make.
I have been thinking about what sort of an amp
(preamp) would be needed to pick up their sounds.
Would an off the shelf part work or maybe a op amp?
i think you would need a microphone,and preamp for each location, plus a switcher plus amp to monitor the sounds. you cantry and look for a condenser mic preamp and mechanical switches plus a simple amplifier maybe lm 386 based with a small speaker or even headphones. check at sound westhost site.
Probably you need a system similar to biomedical systems. You need a microphone instead of electrodes and follow it up with preamp. This must be followed by filters to filter out unwanted frequency components. For this you need to know the exact frequency pattern of the termites. Finally you need a simple event detector like a comparator.