I had some Arduinos and some PICs lying around the garage, but they were allocated to some other projects and I didn't want to touch them.
So when I got a Arduino Nano last month I decided it was time to spend a Saturday working on my hydroponics prototype.
Strawberrys and lettuces.
So I hacked some PVC pipes, a small fountain water pump, a 433Mhz remote controller 2 channels with a receiver equipped with 2 220V capable relays.
The fertilizer I use in the water is also homemade, humus based, produced by earth worms. They eat leftovers from vegetables, fruits and... well... horse shit.
I programmed the Arduino to water more during the day and less during the night. Next step would be incorporate some temperature sensors, light sensors and humidity. And solar power it all. Pretty permaculturish.