Multiplexing and splitting item streams:

[Iakovosian]

Rather than continue to derail a suggestion topic, I've moved my findings to here.


I understand that an item stream (a water stream with multiples of the same item floating in it) can be split by alternating the directional flow of water in a timed pattern. I felt this was a slightly over-engineered solution, and thought of this following method. Not sure if anyone else has come up with it already.

By placing a siding underneath the water flow, side-on to the flow direction, you can siphon off all items travelling on the opposite side of the stream. This can be done in two orientations, and then leaves the items that were travelling down the middle of the stream. After running several tests I found that, in my example, the number of items travelling down the middle of the stream was slightly less than those travelling on one side or the other (but this can theoretically be adjusted by moving the glass panes - that stop the BD throwing things too far - closer to the BD). When throwing 9 stacks of wheat into the input stream I got, on average, 3.5 and 3.75 stacks on either side and 2.75 stacks down the middle.

This configuration only works when the items in the water stream are (semi-)randomly distributed from side to side. This could potentially be straight from an auto-farm, if the items are taken away in the right direction, or by the setup shown in this example: A powered hopper over a pulsed block-dispenser.

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View showing the three divided outlets from the single input stream.


Top-side view of the input stream, and the three 'filter' types.


Just showing the stream from <enter location here> leading into a powered hopper, then a BD to fire the items individually in a slightly random direction. (Pistons also seem to send plants flying in a slightly random direction too, but the BD was better suited here for illustration purposes.)

[Iakovosian]

Nice design has given me lots of ideas. like having two types of item run down a single stream just on different side.

You can do more than just two. I think you should be able to send 8 different item types down a stream and still be able to separate them all at the other end. However, two of the 'item filters' are iron bars (or equivalent) and fences which let items fall down on both sides so some things have to be extracted in a slightly more complicated order (I know the theory of how to do this, but haven't yet built it). Excluding those two, you should be able to send 6 different item types down the same water stream. I tested this out, and here is what I found:

The Story:

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I tried to find as many blocks of different width when placed sideways, and these are the ones I found:
Iron bars and fences were left out of the final design since they would severely increase the complexity of the extraction.


So, after building the injection system (I just used dispensers shooting items against the relevant blocks) and the extraction system, with a short distance in between, I am ready to start it off. I used different colours of wool as test items with a single stack in each dispenser.
"There they go!"


"Here they come..."


"The moment of truth..."


"It works!" :)


"Time for the results..."

The Results: (from right to left)

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Off to a very good start...

Still going strong...

Uh-oh, where're the other two blues?

Well there's one of them, but what's that white doing there?

There's one of the yellows...

Okay, not too bad, I guess.

Conclusion:
It seems to work very well indeed but not quite 100%, unfortunately. If someone could try to work out the exact cause of the few anomalies, please let us (and me) know. I can think that it might be down to an occasional erratic throw by a dispenser, or perhaps the sheer volume of items managed to push one or two out of place? Not sure. Would be interesting to find out the limits of this system - whether it becomes more reliable if fewer item streams are used in the same water flow.

[razar51]

Wow, can't believe I never thought of this, quite a cheap and easy way to split items up! Good job.

[Iakovosian]

When testing out normal dispensers in place of block dispensers in the op's design, it seems their shots tend more to the sides than with the BD. Not confirmed with enough test runs yet, though. If this helps reduce the number of items flowing down the middle of the stream, perhaps it would be feasible to create some kind of feedback loop to send those remaining items back through the splitters again.

Following on from that, I've heard mention of (but not seen) ways to transport items in water with no drop every 8 blocks. Does anyone know how this is done? Also, is there a way to raise items upwards in a water system or is a pulley lift the only way? Not meaning to complain about the pulley and platforms - they are amazing on so many levels (excuse the pun) - but they're not the smallest of contraptions to incorporate.

[ialdbaoloth]

I've heard mention of (but not seen) ways to transport items in water with no drop every 8 blocks.

Here's a nice video, though it's not the earliest.

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[Stormweaver]

Also, is there a way to raise items upwards in a water system or is a pulley lift the only way? Not meaning to complain about the pulley and platforms - they are amazing on so many levels (excuse the pun) - but they're not the smallest of contraptions to incorporate.

You can use pistons/BDs to force blocks to occupy the same space as an item, which done right will force it upwards. Search 'Archimedes screw' here and you should find a few examples people have made (haven't seen one for a while though).

[Iakovosian]

Thanks for the links & suggestions.

I've also thought of a more consistent way to feed items into the multiplexed water flow (feels weird calling it that). I'll have a play, and get back to you with my findings. :)

I'm also investigating a way of being able to turn corners with this system (if it's even possible), and to be able to use the flat water stream transportation methods with it too.

[Blazara]

Thanks to this topic, my semi auto wheat farm now sends wheat to my breeding area, my larder in the base near the farm, down the mine to keep me stocked up whilst mining and also into transport carts to be sent to my other base! They pretty much all get the same distribution of wheat!

[sargunv]

There's a way to transport items horizontally without water, but it requires a lot of cake.

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[MoRmEnGiL]

Can;t you do the same by just alternating a full and a half block instead of fence under cake? Or do items fall through blocks due to the glitch?

[sargunv]

Can;t you do the same by just alternating a full and a half block instead of fence under cake? Or do items fall through blocks due to the glitch?

Yes, but I'm not sure if it works for items. The player can fall through this one though.

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[Iakovosian]

Well, I managed to achieve part of what I wanted but not quite all. Didn't upload earlier because of Christmas happening.

Turns out just putting ice under the water flow magically and consistently increases the items' momentum enough to make it always hit the far wall and whatever object you've placed in the way. Hopefully we'll have ways of picking up ice legitimately eventually. At the moment, placing water sources in a snowy biome works well enough to freeze the ice and, if you feel up to it, you can piston it all the way back to your base! ^_^

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This method was tested with 18 stacks of wool of each colour, and every single one of those 6912 items went into exactly the right place, leaving a very satisfied person indeed! :)

P.S. I also put ice under the main water stream to just speed up the items' flow.

As for horizontal transport, using the cake walkway is currently the only way to preserve the horizontal spacing of the items. Or you could still use water flows and have a platform lift to bring the items back up again every few chunks (requires flood gates to stop items falling into oblivion when the pulley is moving).