I built a bat detector some time ago but never really got a chance to try as the bats seem to have left.
Fetching the detector from the workshop, I pointed it at the trees, switched on and waited… and waited… and waited… eventually some quick audio bursts were heard and we saw the culprit fly past; doing some rather impressive aerial manoeuvres as it happens whilst catching his dinner.
So, I know the detector works, but the next job is to increase its sensitivity – that’s this weekend’s project.
Once it’s done, I’ll post up the circuit here.
The weekend came... the weekend went... as did the summer.
Looks like I'll have to try this again next year.