A manual row without machinery
Place the landing block next to the water at the same level: a common side is needed, a diagonal touch is not enough. Plant one sugar cane and leave room at the top for up to three segments to grow. Sand does not provide any special acceleration relative to normal ground. Reference: Minecraft: observer.
When collecting manually, break the second segment from the bottom: the top one will also fall out, but the base will remain. Three sugar canes in a horizontal row yield 3 paper; one sugar cane turns into one sugar.
One module in section
Label the lower segment of the plant Y=1. At Y=2 place the piston on the side facing the plant. Directly above the piston, Y=3, place an observer facing the third segment square. The red exit faces backwards.
Place a solid block behind the piston at Y=2, with dust on it Y=3: it receives the observer output and powers the block near the piston. Cover the front area with walls, but leave the plant and piston free. Apply water to the base from the side, outside this cut.
First check the direction and pulse of the sensor: Minecraft observers: facing direction and pulses.
Test harvesting and item loss separately
Manually build the sugar cane to the third segment. The piston should knock down the top two and not touch the base. Wait until it is quiet: removing a segment may trigger another sensor trigger. Then wait separately for natural growth.
Count where 2 dropped items are located. Some may remain on the landing block, so a water channel on the side does not guarantee complete collection. For a simple stand, assemble by hand; When automating, check the trolley with the hopper under the base or the extended receiver before copying the row.
To connect the receiver to the chest, the following instructions will be useful: Hoppers: send items to the right container.
