Melon and pumpkin farm that fully automatically detects growth and then harvests.
This completely automated farm does not need any external intervention, i.e. it harvests itself without flipping a switch and remains thereafter until the next growing of a pumpkin or melon.
Everything is collected by a box, which is supplied by a hopper at the end of a water flow.
As soon as the plant grows, the Redstone mechanism closes and releases the cobs.
(no repost statements please ... similar ideas have been around but not so "simple").
Instructions:The construction is very simple and can be seen in this picture:
(1x funnel + 1x box)