midi trigger for outdoor drums played by rain

[Romeo Suave]

I am planning to build outdoor drums that will be played by the rain. I live near Seattle so that for much of the year we have no lack of rain. What I want to do is to build a midi trigger inside the drum. Where I see the problem is that midi triggers are monophonic and rain would obviously be polyphonic, so that maybe it would just work ok, but I suspect that I need a brain that would interpret just one event and ignore poly events? I also suspect that the
ardruno computer would work for a brain with the right program or one of the old alesis drum brains. Anyway, could use your thoughts on poly triggers or to make a mono trigger work and a midi brain so that I can trigger samples, loops or lights from a midi trigger. The last issue is the distance between the trigger and the brain, because If I need to keep lengths short, that would mean weather protection for the electronics. anyway, any thoughts?

[David King]

I hope Veronica can pipe up as I'll bet she would know.

[Mark Swanson]

How many drums would you like to control? And I don't see why it would need to be polyphonic, real drums are not- they play just one voice per drum. If I were you I'd build a different MIDI trigger in each drum, that will send a different and hopefully programmable note out of each drum. Then you could assign each note to the voice of your choice. Rather than polyphonic, I would make it velocity sensitive, so that a harder hit plays a louder note and a lighter hit plays a softer one. That may be very hard, because raindrops don't hit very hard at all anyway. In fact it may be hard to get a raindrop to trigger anything, they don't have much energy.

[Romeo Suave]

If I use the paia midi brain, they will accept 8 triggers, so if I need more, it is more brains.
The problem is like what we experienced back in the early days of Moog and Arp synths, where it would only play one note at a time, it may be that 60 rain drops hit the drum head at the same time or near the same time, might freak out the midi brain, but it may not be a big deal. I don't know. I may be anticipating problems that don't exist. Likely I will have midi trigger ICs with sounds in them or use some kind of computer to choose sounds at random. Using the ICs means I don't have to have a computer.