I'm far from a redstone engineer :P but I help Phrozen on the RedSignal server and I try to build some redstone things too.

So for my first finished project I wanted to do something simple and practical. I wanted to create a melon farm which would automatically harvest at night. At first I couldn't make it like I wanted, because the daylight sensor would keep the pistons extended the entire night. Only after seeing other people build redstone contraptions with observer blocks, I knew how to make my daylight sensor send out a pulse. The daylight sensor has a block-update whenever the sun goes up or under. :D So whenever that happens, the melons are harvested and they float through the water into a chest.

Easy to use in vanilla survival Minecraft, this farm should also work with pumpkins. ^_^

Feel free to use this little melon farm in any way you like. :D The schematic is included but it may need some fixing/replanting seeds when you place it in your world.