More than 30° Celcius (ie. more than 86° Fahrenheit) is quite hot if you are a rabbit. As we keep some handtame rabbits in an outdoor rabbit warren, we thought of how it could be possible to reduce the temperature in an open area. This is a problem probably not being solved with electronics or software at all unless you plan to include liquid nitrogen in your solution.
Eventually, we found this awesome cooling set from Gardena (Amazon affiliate link). I was pointed to it last year by Clemens as he tweeted about it in his rabbit warren.
Originally designed for the convenience of human beings, it turns out, this is quite relaxing for rabbits as well. The system creates a very fine mist cooling down the sprinkled are several degrees.