19-04-2020, 05:03 PM
I lifted the design from an old Scientific American with my mods.
Consists of pipe with two inverted funnels, one at top (blue in photo)
Other near bottom.
Two concentric varnished and insulated cylinders mounted just below
bottom funnel. (as shown)
A differential amp is mounted at end of cylinders.
Each amp input connected to each cylinder.
The two funnels hole size made to only permit raindrops to fall through inner tube.
All others are rejected through side slots in main tube.
As a charged raindrop falls through inner tube it induces a small charge on that tube
and so amplified and feed to computer display with suitable software (Dataq)
Most recent experimental mod of mine, not shown is a bottom plate detector that the raindrops hit on exit and
so create a small voltage, This will depend on raindrop size and velocity, to be displayed
as well.
I was considering another idea, a sagging horizontal wire which could be given a jolt to remove raindrops
after charge was measured. Because this idea is so simple it probably wouldn't work !
