Mechanical first rain drops detector?
I am looking for a mechanical' 'way of detecting the first raindrops of a shower or worse.
This detector then releases a mechanical alarm, which will alert folk who keep their washing on the line as long as possible, to bring it in.
The alarm could be sounded by a gravity falling weight (rock) or rewindable spring, driving a rattle, for example.
If possible, a windmill action could generate the power to reset the weight.
No electronics to be used in this if possible.