[JT118]

For the real DIYers:

Could make this as a wired version;

http://www.allaboutcircuits.com/projects...-the-base/

and calibrate as per page 3, post 30,
"Correct way to calibrate and check Rain Gauge:"

http://www.meteocercal.info/forum/Thread...264?page=3
would be as good as FO gauge, maybe better, depending on your maths. Sharpening the top edge of the funnel would improve the gauge.