rain sensor

[greencircle]

Can rain pour be used as a signal to switch a motor ON/OFF?

I have a plant nursery setup for a horticulture research project. The whole shelter moves on rails (motor operated). We need NO shelter when there is NO rain. But need to be protected from rain (I know its crazy).

Is there a way to automatically sense rain and operate motor?

 

[asimpson]

http://www.amazon.co.uk/s/?ie=UTF8&...vptwo=&hvqmt=b&hvdev=c&ref=pd_sl_3smduh762b_b

Automatic windscreen wipers:

https://www.google.ie/search?q=auto...a=X&ei=qs6BVMn0MKPY7AbJxIC4Ag&ved=0CAYQ_AUoAQ

 

[btrueblood]

Of asimpson's two choices, take the 2nd, optical method. The first link shows a variety of "conductivity" sensors, i.e. the rain drops short-circuit a portion of a grid of electrodes to give a signal change to flip a switch. While this method works in the short term, over time the corrosion of the grid gives unpredictable results.

 

[greencircle]

That's a great lead. I never knew this. Thanks guys.

 

[mcgyvr]

Many "sprinkler" system can incorporate an off the shelf "rain sensor" too..

 

[telecomguy]

And just as a side note, when my sprinkler system rain sensor stopped working, and being a mechanical engineer, I just had to tear it apart to understand what's going on. Pretty simple once I got in there. Before that, I thought it had some kind of humidity sensing electrical component or something. Never knew it was a simple mechanical switch. They just have a cup that catches rain. In the bottom of the cup is a rod going thru a sealed hole. The rod has a couple of felt washers with a cap on the end of the rod. On the inside, there was a spring pushing that rod down onto a switch. When the washers get wet, they swell up, lift that rod (compressing the spring), and open the switch so the sprinklers don't run.

Turned out there's a coin cell battery in there because it's a wireless signal back to the control panel. Replaced the battery and I was back in business.

http://www.rainbird.com/landscape/products/controllers/RSD.htm

-tg

http://xternal.me