Below is a full, detailed description of how it works, but here I will just tell you what it does: When the single chest at the end of the automatic sugar farm with a hopper feeding into it fills up to all but about 1 and 3/4 stacks, the sugar cane farm automatically stops pulsing in order to keep the chest from overflowing. Once a player takes out a certain amount of sugar cane, the mechanism will automatically restart and continue until the chest reaches a certain number of items in it. From there it goes in an eternal loop of what was previously mentioned.
(This may be easier to comprehend after looking at the picture) On the back part of this, there is a (single) chest with a hopper on top to collect the sugar cane and a comparator coming out of the side of the chest to sense the amount of inventory it has. Once the chest fills up to a certain point, the redstone signal will reach a not gate (I believe either 14 or 15 blocks after the comparator) and turn around to head back to two places: 1. a sticky piston holding out a block to complete the clock, and 2. to reset the mechanism used to output a 1 tick pulse. Therefore, the redstone clock's pulse will be terminated (this will take at most 10 seconds). When the player takes a certain amount out of the chest, the redstone signal will not quite reach the not gate gate and therefore turn on the output by the wire after it, triggering the piston to push the block completing the clock back out to ready the circuit for the pulse and the mechanism (I'm not sure if it needs to do this but it goes through a double not gate) will have a redstone torch triggered in order to output a 1-tick pulse back into the circuit. On final notes, the clock lasts about ten seconds before pushing out the pistons and pushing the sugar cane into the water using a simple mechanism, and no, the blocks do not need to be redstone blocks, that was just the only block in my inventory at the time. Lastly, this mechanism may work better if you move the hopper 1 block down from the edge of the water instead of right up against it because, some items do not go in to the hopper if you put it right next to the edge of the water flow, and if you were to widen the stream in the middle of the mechanism, it would heighten efficiency, as you would lose less sugar cane going off to the sides. (Sorry for this description not being in a completely logical order ).
P.S: The daylight detector and the command block in the middle are not part of the system. They are just there to automatically change the time back to day when it gets dark. Also, the many comparators on the line feeding back towards the viewer are not necessary, they are just there to make the signal move quicker than with repeaters. Basically, unless a comparator is specifically mentioned, it is not necessary.
WARNING: Make sure you give the mechanism at least a ten second cool down after it stops the sugar cane machine before getting any sugar cane out of the chest to make sure that the first pulse is terminated before a second pulse is put into the clock. otherwise the machine may not work as well or even at all and someone will have to manually fix it by putting a certain items into the chest, waiting ten seconds, and taking them back out.
If you want a better screenshot, or one of the sides and back, just tell me.
(This may be easier to comprehend after looking at the picture) On the back part of this, there is a (single) chest with a hopper on top to collect the sugar cane and a comparator coming out of the side of the chest to sense the amount of inventory it has. Once the chest fills up to a certain point, the redstone signal will reach a not gate (I believe either 14 or 15 blocks after the comparator) and turn around to head back to two places: 1. a sticky piston holding out a block to complete the clock, and 2. to reset the mechanism used to output a 1 tick pulse. Therefore, the redstone clock's pulse will be terminated (this will take at most 10 seconds). When the player takes a certain amount out of the chest, the redstone signal will not quite reach the not gate gate and therefore turn on the output by the wire after it, triggering the piston to push the block completing the clock back out to ready the circuit for the pulse and the mechanism (I'm not sure if it needs to do this but it goes through a double not gate) will have a redstone torch triggered in order to output a 1-tick pulse back into the circuit. On final notes, the clock lasts about ten seconds before pushing out the pistons and pushing the sugar cane into the water using a simple mechanism, and no, the blocks do not need to be redstone blocks, that was just the only block in my inventory at the time. Lastly, this mechanism may work better if you move the hopper 1 block down from the edge of the water instead of right up against it because, some items do not go in to the hopper if you put it right next to the edge of the water flow, and if you were to widen the stream in the middle of the mechanism, it would heighten efficiency, as you would lose less sugar cane going off to the sides. (Sorry for this description not being in a completely logical order ).
P.S: The daylight detector and the command block in the middle are not part of the system. They are just there to automatically change the time back to day when it gets dark. Also, the many comparators on the line feeding back towards the viewer are not necessary, they are just there to make the signal move quicker than with repeaters. Basically, unless a comparator is specifically mentioned, it is not necessary.
WARNING: Make sure you give the mechanism at least a ten second cool down after it stops the sugar cane machine before getting any sugar cane out of the chest to make sure that the first pulse is terminated before a second pulse is put into the clock. otherwise the machine may not work as well or even at all and someone will have to manually fix it by putting a certain items into the chest, waiting ten seconds, and taking them back out.
If you want a better screenshot, or one of the sides and back, just tell me.
Screenshot here: