(02-09-2018, 09:17)engolling Wrote: But what I already thought about - if I install a bigger funnel over the fine offset gauge i can make it more precise.
Yes, I have experimented with a 15 cms diameter funnel to increase the FO resolution to about 0.1 mm/tip. First I tried a plastic funnel but the raindrops appeared to "hang" on the plastic so it did increase the resolution, but did NOT advance the warning that "it's raining". However, recently I have tried a "Stainless Steel" funnel from ebay (only a few Pounds/Euros, locally sourced or from China), which does appear to significantly improve the "Rain" warning.
But back to the OP, perhaps more expensive (but IMHO not unreasonable if sourced directly from the manufacturer in USA) is the Hydreon RG11 optical sensor. It uses the same technology as automatic windscreen wipers, but has several modes of operation including "it's raining" (for roof windows, etc.) and also emulates a tipping bucket sensor with (optionally) very much higher resolution (0.01mm or even higher !). It was discussed on the Sandaysoft Forum about 6 years ago (and has limited support in Cumulus 1) where the consensus was that it is not as accurate as a well-maintained tipping bucket, but it needs less maintenance (perhaps just a treatment of "Rain-X" every year or so).
I hope to test mine soon; it wasn't compatible with the power-levels of the Fine Offset station (a few AA cells!) but it needs less power than an Arduino Nano. The "standard" supply is 9v+ (dc or ac) but it can be connected to +5v dc if desired. A 5v, 9v or 12v (battery) supply could be "patched" onto the RJ-11 "Rain" socket of the Universal transmitter, but I have several more suggestions to make if an "update" to the Transmitter PCB is planned.
Cheers, Alan.