I was thinking about adding an automatic trash sorting to my XP furnace. The basic idea is that I have an input chest where I put all items that I don't need, and things that can be used to power a furnace (wood items, dried kelp and such) would be redirected to my furnace while the rest is thrown into lava. Such automatons are highly convenient: I often play with my 9yo daughter, and even though she has an amazing Minecraft knowledge, in practice she is not that organized. The automatic storage was maybe the most important addition to our world So I'd like to tell her "here's a chest, just dump in what you want destroyed".
Now the number of items usable as fuel is quite large, and an auto sorter takes up a lot of space and is a pain to initialize if you want to sort 30 or more different items. It would be much easier to set up a chest or a dropper, fill each slot with one of the items that I want to redirect to the furnace and set up 27 items that can be burned. But I suppose there is no way to rig this, is there?
Identifying non-burnable items can be done this way of course. Have a hopper point into some storage with every slot filled, and a locked hopper below that which is unlocked some time after the first hopper receives an item. So if items can't go into the chest, they will move to the lower hopper.
But this design does not get the burnable items out, and there is a limit to the number of items that can go into the chest (one stack per slot).
Yeah, it feels wasteful but it would be a lot easier to just set up an auto farm for bamboo or kelp or something to fuel the furnaces and trash the fuel items along with the rest.
All my ideas for actually using them as fuel, via the chest based sorting you describe, involve some manual steps, and guesswork.
#1 manually move items from the sorting chest(s) to chests hooked up to the furnace fueling system every now and again, like when you have a new load of trash.
#2 set up double sorting chests, have one set filling with automation that detects when the fuel buffer empties, switching that set to empty into buffer chests fueling the furnaces,start filling the other and lighting an indicator so you know to set the first set up ready to be switched to fill next.
--
Perhaps you could do the full auto sorting directly into the fuel system for the most high volume trash items and the rest would hopefully accumulate slowly enough that you didn't have to switch/reset the sorting chests all that often.
(Of course the relative volume of the various trash items is likely to vary depending on what one has been working on recently.)
If we could duplicate the contents of a container, or reliably move one of each item.....
Set up something with at most 15 slots. Put one item in each slot. Duplicate. The duplicate is used as filter, as soon as the comparator reads a higher fill grade (meaning there is half a stack of items or so in there), suck out all items and duplicate again.
If we could duplicate the contents of a container, or reliably move one of each item.....
Set up something with at most 15 slots. Put one item in each slot. Duplicate. The duplicate is used as filter, as soon as the comparator reads a higher fill grade (meaning there is half a stack of items or so in there), suck out all items and duplicate again.
Ah, ideas
Yeah!
Unfortunately that would, itself, probably require a full autosorter.
Using a full autosorter to make a simplified autosorter sounds pretty Rube Goldbergish. ;-)
Too bad you can't get fuel back out of a furnace or you could use furnaces to do the sorting, just into burnable/non burnable, no need to separate sticks from fishing rods etc.
I suppose one could use a mod (or command blocks) that allowed furnaces to be automatically mined and placed.
T.N.T. might work for breaking them. ;-)
--
Or you could try Satisfactory, that game has programmable splitters, 1 simple machine that can sort out up to 64 different items. ;-)
(It only has 3 outputs so a full sort would still take half as many splitters as item types but it would be perfect for a case like this with only 2 categories.)
I use the multi-item sorter (v4.0 or v4.2) that was made by Datnerd, Rapscallion1138, metamilo, and some others at the end of a hopper line that connects all my mini auto farms (and an input chest) to sort for the "cookable/smeltable" items and sends the rest through to the storage room (which uses the v4.2 of the sorter). One slice can sort for up to 54 different items (one double chest), which makes it more like a categorizer. I've included a link for the v4.0 and v4.2 below; the v4.2 requires a little modification for single slice use, but it is insanely fast.
For your case, you'll probably do the opposite and sort for the fuel sources (though, it won't include the non-stackable stuff). Then, have a hopper that moves items from the bottom (where the sorted items go) into the side of your furnace/furnace array so that it's used as fuel.
Alternatively, you could put it at the end of an automatic item sorter for your storage, and have it receive the overflow lines from slices that sort for possible fuel sources. You will still have the issue of non-stackable items, but you can separate those with a simple non-stackable item filter (I linked 2 designs below for this). It's been some time since you asked this question, but hope this can help if you're still trying to find a solution.
Setting up a filtering chest where each slot has some item can work for storage sorting - as long as user remember to leave an item in slot when taking stuff out - but setting that up as automated feed for furnace fuel would be a nightmare. There is really no practical way to tell a system to leave a single item in each slot.
You could, as proof of concept, concoct something that will distribute items to a bunch of hoppers that would try to push thiose items into furnaces. and anything that fails (either cause it is a non-fuel or cause furnace already has fuel) gets circulated back to source.
But seriously, if that is trash, just trash it. Set up a high-volume bamboo farm and use that for automated fuel supply.
If it's something you have an unending supply of, like cactus from a cactus farm that you can just make bigger if needed you could split the stuff to be smelted into two lines, one going to furnaces fueled by your main fuel supply and one fueled by trash.
I'm thinking that if you have enough furnaces then just passing the trash past the fuel slots could sort out most of the burnable stuff, particularly if you loop the trash back again as long as the trash chests aren't overflowing.
Once a furnace has picked up a piece of burnable trash it would act as a sorter for that type of item until it had filled a stack. (Assuming it's stackable of course.)
That way you wouldn't be wasting all that trash (possibly some of it depending on the amounts of trash and the size of the trash buffer.)
You would be "wasting" furnace capacity (but that's cheap as long as you have the space) and creating a buffer for whatever you are smelting which might or might not matter.
Anything smeltible that you have a limited supply of should go to the line that's reliably fueled (assuming you have that.)
If you wanted you could keep the outputs of the two lines separate as well so you can show your daughter, "this is what your (or our) trash has produced".
I did have another idea involving holding back the reliable fuel until the trash runs out but I'm not quite sure how to switch back to trash once the furnaces have filled up with the reliable fuel after the trash runs out.
I think it might be able to be done by holding back the reliable fuel until the trash runs out and then holding back the trash until the furnaces stop outputting smelted items (or the smelted item output drops below a certain rate).
The reliable fuel could just be held while there is unprocessed trash but once the trash starts flowing it should keep going until it (the trash) runs out again.
If you want the maximum utility from the trash perhaps the trash could be looped back until smelted output drops again
You could, as proof of concept, concoct something that will distribute items to a bunch of hoppers that would try to push thiose items into furnaces. and anything that fails (either cause it is a non-fuel or cause furnace already has fuel) gets circulated back to source.
But seriously, if that is trash, just trash it. Set up a high-volume bamboo farm and use that for automated fuel supply.
I do have a high-volume bamboo farm For me, the fun is in designing neat and efficient solutions. Like not wasting any potential fuel
I like your idea, but I'm not sure if it is practical. If we could get fuel out of furnaces using hoppers, this would be ideal: Have a locked hopper below the one leading into the furnace, and cyclically unlock it when no new items come in. At the same time, get the fuel out of the furnace.
However, as I don't know a way to get fuel out of furnaces, this gets tougher. I have 2 furnace arrays where I could use "combustable trash", an XP smelter that runs cactus/bamboo all the time and a small furnace array that smelts whatever else I want to smelt. With the XP smelter, I have some redstone circuitry to make sure no bamboo is wasted and also to make sure that there is always dye in the furnace that I can take out, so I can't add another logic circuit attached to the furnace simply because I lack space. With the other smelter I'd like to have a reliable fuel supply that keeps my furnaces ready. But if the furnaces are filled with fuel and aren't smelting anything, the sorting wouldn't work.
I did have another idea involving holding back the reliable fuel until the trash runs out but I'm not quite sure how to switch back to trash once the furnaces have filled up with the reliable fuel after the trash runs out.
I think it might be able to be done by holding back the reliable fuel until the trash runs out and then holding back the trash until the furnaces stop outputting smelted items (or the smelted item output drops below a certain rate).
I'm kinda afraid that this would require more redstone circuitry than a normal item sorter, since every furnace would need the logic to push items along that aren't usable as fuel
The problem is that we don't know if a furnace is low on fuel or low on input items. If it reads zero, obviously there is no fuel. But if it reads one stack, it may be one stack of fuel or one stack of input... And if we have an unlimited supply of input (say from a cactus farm), there is no redstone signal that distinguishes between 64 and 65 items.
Counting output items could be done, but that would be quite a lot of circuitry for each furnace.
can't you just point a hopper into the furnace side and put a hopper below that hopper? then do some comparator magic to slow the thing so it works properly
I haven't tested it but the Wiki says hoppers push before pulling so I'm hoping the hopper on the side of the furnace pushes if it can (if it has fuel and either the furnace is empty of fuel or has the same fuel and room in the stack) then the next hopper pulls an item from it if it has one left.
and the test of if the trash has run out would only be done once, after the last furnace and the test for if the furnaces have started to run out of fuel would be done on the output line.
It would require the furnaces be either placed in a stepwise formation requiring twice as many hoppers, an extra hopper inbetween each pair of furnaces or in double vertical rows, every other furnace to the left, every other to the right (to leave room for the hoppers removing the smelted products.)
The way I'm thinking it would work is, as long as the trash has any burnable items left they would be placed in the first furnace that has room for them, as soon as any furnace stops producing smelted items you know the trash has been depleted and stop looping it, instead sending it to your lava pit.
When the trash has been sent to destruction so the storage chest is empty the bamboo gets let through, either though the same hoppers as the trash or through hoppers on the other side of the furnaces.
At this point most of the furnaces will still be smelting but the bamboo should fill up any furnaces that have run out of trash, so the drop in production shouldn't be very large as long as you can accurately determine when the smelted output slows down.
I'm probably being overly optimistic about determining when the furnaces start to stop, I was thinking that could be done with a timer but I guess it would probably require a counter combined with a timer of some sort unless you're willing to wait until most of the furnaces have run out of fuel, if you're only emptying your trash a couple of times a day that might be acceptable.
It would certainly be easier to have a few furnaces set aside to process the trash though and either just accept them standing idle most of the time or wait until nearly all of them have run out of fuel (as determined by a simple timer on the smelteds output) before turning on the bamboo again.
can't you just point a hopper into the furnace side and put a hopper below that hopper? then do some comparator magic to slow the thing so it works properly
No
I mean yes, but with ~30 combustible trash items and only one slot in the furnace, if an item doesn't go in then it could mean that it's not fuel or it could mean that a different item is in the furnace. And with some things burning forever (coal 80s), others really fast (bamboo 2.5s) there is no way of knowing if we need more fuel or not.
I actually have a design for auto cooker/smelter things before it goes into my sorting system that uses a dropper facing the side of the furnace with a hopper under it. when the dropper is powered it'll try to push the item into the furnace and the hopper under it is locked momentarily. However, this means that there won't be a build up of items for fuel like you're trying to do; if the furnace already has enough fuel, the items would just go straight into storage system. I do use one MIS v4.0 before the furnace to split up items that I want cooked or smelted before it's sent into the auto cooker/smelter.
I also use a system that uses the fill level of chest to control the locking/unlocking of a hopper under it for auto trashing using a comparator in subtract mode reading from that chest with another comparator pointing into the side of the first comparator that is reading the fill level of another chest. This allows me to set how filled up I want a chest to be. You might be able to set this up to toggle between which chest to use fuel from.
I haven't tested it but the Wiki says hoppers push before pulling so I'm hoping the hopper on the side of the furnace pushes if it can (if it has fuel and either the furnace is empty of fuel or has the same fuel and room in the stack) then the next hopper pulls an item from it if it has one left.
Didn't notice this at first reading.
It's a bit more complicated. Say hopper A goes into the side of the furnace, and hopper B is below hopper A, then any item going into hopper A would go into B and not into the furnace. The only way around this is to lock B. Then cyclically lock the hopper pointing into A and unlock C.
But that makes a build with lots of furnaces difficult: Items will go down if the furnace can't accept them, so I would need tons of elevators to move them up. Or have furnaces below each other, which isn't neat. Or am I missing something obvious?
That's why I'm hesitant to build this with extra 30 furnaces (to sort out 30 kinds of fuel). Each furnace needs the same redstone circuitry. And they would need extra redstone to control the supply of items to be smelted. (As XP farm these extra furnaces won't produce XP enough to matter. For all other stuff I don't want the item to be smelted get stuck in a furnace where perhaps no fuel comes in for weeks.
If we could push furnaces around that would be neat - just build a wildly complicated redstone circuit to handle one furnace, and switch it out every other second using a conveyer belt
The way I'm thinking it would work is, as long as the trash has any burnable items left they would be placed in the first furnace that has room for them, as soon as any furnace stops producing smelted items you know the trash has been depleted and stop looping it, instead sending it to your lava pit.
When the trash has been sent to destruction so the storage chest is empty the bamboo gets let through, either though the same hoppers as the trash or through hoppers on the other side of the furnaces.
At this point most of the furnaces will still be smelting but the bamboo should fill up any furnaces that have run out of trash, so the drop in production shouldn't be very large as long as you can accurately determine when the smelted output slows down.
I'm still not sold on the "measure smelted items" idea. Not for the XP farm where I have constant supply of cactus, because I have redstone to control that some dye is always kept in the furnace to take out, so there is no space for more redstone circuitry. (I already use 5 sides of each furnace. One to access, top for cactus, side for bamboo, back for reading the furnace, bottom for sucking dye out.) And for the other smelter there is no reliable supply of items to be smelted.
I also thought about reversing the logic: Accept items to be smelted only if the furnace has enough fuel. (Which can be done with a bit of redstone, I think.) That way, we could move the ore or whatever over all the "trash burning" furnaces first, and then have them end up at a few furnaces that have a supply of bamboo. But this doesn't solve the problem of the trash/fuel transport: Once an item gets into a hopper pointing at a furnace, the only way to get them out is by sucking them out with another hopper below. Which has to be locked with redstone to give the items time to go into the furnace, if possible. So this system would need a ton of space, and several elevators.
Still haven't gotten around to a detailled look at the multi item sorter. It's on my watch list. But so far, I doubt that our solutions are better than to to just build an extra sorter...
I was thinking about adding an automatic trash sorting to my XP furnace. The basic idea is that I have an input chest where I put all items that I don't need, and things that can be used to power a furnace (wood items, dried kelp and such) would be redirected to my furnace while the rest is thrown into lava. Such automatons are highly convenient: I often play with my 9yo daughter, and even though she has an amazing Minecraft knowledge, in practice she is not that organized. The automatic storage was maybe the most important addition to our world So I'd like to tell her "here's a chest, just dump in what you want destroyed".
Now the number of items usable as fuel is quite large, and an auto sorter takes up a lot of space and is a pain to initialize if you want to sort 30 or more different items. It would be much easier to set up a chest or a dropper, fill each slot with one of the items that I want to redirect to the furnace and set up 27 items that can be burned. But I suppose there is no way to rig this, is there?
Identifying non-burnable items can be done this way of course. Have a hopper point into some storage with every slot filled, and a locked hopper below that which is unlocked some time after the first hopper receives an item. So if items can't go into the chest, they will move to the lower hopper.
But this design does not get the burnable items out, and there is a limit to the number of items that can go into the chest (one stack per slot).
Yeah, it feels wasteful but it would be a lot easier to just set up an auto farm for bamboo or kelp or something to fuel the furnaces and trash the fuel items along with the rest.
All my ideas for actually using them as fuel, via the chest based sorting you describe, involve some manual steps, and guesswork.
#1 manually move items from the sorting chest(s) to chests hooked up to the furnace fueling system every now and again, like when you have a new load of trash.
#2 set up double sorting chests, have one set filling with automation that detects when the fuel buffer empties, switching that set to empty into buffer chests fueling the furnaces,start filling the other and lighting an indicator so you know to set the first set up ready to be switched to fill next.
--
Perhaps you could do the full auto sorting directly into the fuel system for the most high volume trash items and the rest would hopefully accumulate slowly enough that you didn't have to switch/reset the sorting chests all that often.
(Of course the relative volume of the various trash items is likely to vary depending on what one has been working on recently.)
Just testing.
If we could duplicate the contents of a container, or reliably move one of each item.....
Set up something with at most 15 slots. Put one item in each slot. Duplicate. The duplicate is used as filter, as soon as the comparator reads a higher fill grade (meaning there is half a stack of items or so in there), suck out all items and duplicate again.
Ah, ideas
Yeah!
Unfortunately that would, itself, probably require a full autosorter.
Using a full autosorter to make a simplified autosorter sounds pretty Rube Goldbergish. ;-)
Too bad you can't get fuel back out of a furnace or you could use furnaces to do the sorting, just into burnable/non burnable, no need to separate sticks from fishing rods etc.
I suppose one could use a mod (or command blocks) that allowed furnaces to be automatically mined and placed.
T.N.T. might work for breaking them. ;-)
--
Or you could try Satisfactory, that game has programmable splitters, 1 simple machine that can sort out up to 64 different items. ;-)
(It only has 3 outputs so a full sort would still take half as many splitters as item types but it would be perfect for a case like this with only 2 categories.)
https://satisfactory.gamepedia.com/Programmable_Splitter
Just testing.
I use the multi-item sorter (v4.0 or v4.2) that was made by Datnerd, Rapscallion1138, metamilo, and some others at the end of a hopper line that connects all my mini auto farms (and an input chest) to sort for the "cookable/smeltable" items and sends the rest through to the storage room (which uses the v4.2 of the sorter). One slice can sort for up to 54 different items (one double chest), which makes it more like a categorizer. I've included a link for the v4.0 and v4.2 below; the v4.2 requires a little modification for single slice use, but it is insanely fast.
For your case, you'll probably do the opposite and sort for the fuel sources (though, it won't include the non-stackable stuff). Then, have a hopper that moves items from the bottom (where the sorted items go) into the side of your furnace/furnace array so that it's used as fuel.
Alternatively, you could put it at the end of an automatic item sorter for your storage, and have it receive the overflow lines from slices that sort for possible fuel sources. You will still have the issue of non-stackable items, but you can separate those with a simple non-stackable item filter (I linked 2 designs below for this). It's been some time since you asked this question, but hope this can help if you're still trying to find a solution.
MIS v4.0
MIS v4.2
Non-stackables end up on top
Non-stackables end up on bottom
Setting up a filtering chest where each slot has some item can work for storage sorting - as long as user remember to leave an item in slot when taking stuff out - but setting that up as automated feed for furnace fuel would be a nightmare. There is really no practical way to tell a system to leave a single item in each slot.
You could, as proof of concept, concoct something that will distribute items to a bunch of hoppers that would try to push thiose items into furnaces. and anything that fails (either cause it is a non-fuel or cause furnace already has fuel) gets circulated back to source.
But seriously, if that is trash, just trash it. Set up a high-volume bamboo farm and use that for automated fuel supply.
What are you smelting?
If it's something you have an unending supply of, like cactus from a cactus farm that you can just make bigger if needed you could split the stuff to be smelted into two lines, one going to furnaces fueled by your main fuel supply and one fueled by trash.
I'm thinking that if you have enough furnaces then just passing the trash past the fuel slots could sort out most of the burnable stuff, particularly if you loop the trash back again as long as the trash chests aren't overflowing.
Once a furnace has picked up a piece of burnable trash it would act as a sorter for that type of item until it had filled a stack. (Assuming it's stackable of course.)
That way you wouldn't be wasting all that trash (possibly some of it depending on the amounts of trash and the size of the trash buffer.)
You would be "wasting" furnace capacity (but that's cheap as long as you have the space) and creating a buffer for whatever you are smelting which might or might not matter.
Anything smeltible that you have a limited supply of should go to the line that's reliably fueled (assuming you have that.)
If you wanted you could keep the outputs of the two lines separate as well so you can show your daughter, "this is what your (or our) trash has produced".
Just testing.
I did have another idea involving holding back the reliable fuel until the trash runs out but I'm not quite sure how to switch back to trash once the furnaces have filled up with the reliable fuel after the trash runs out.
I think it might be able to be done by holding back the reliable fuel until the trash runs out and then holding back the trash until the furnaces stop outputting smelted items (or the smelted item output drops below a certain rate).
The reliable fuel could just be held while there is unprocessed trash but once the trash starts flowing it should keep going until it (the trash) runs out again.
If you want the maximum utility from the trash perhaps the trash could be looped back until smelted output drops again
Just testing.
I do have a high-volume bamboo farm For me, the fun is in designing neat and efficient solutions. Like not wasting any potential fuel
I like your idea, but I'm not sure if it is practical. If we could get fuel out of furnaces using hoppers, this would be ideal: Have a locked hopper below the one leading into the furnace, and cyclically unlock it when no new items come in. At the same time, get the fuel out of the furnace.
However, as I don't know a way to get fuel out of furnaces, this gets tougher. I have 2 furnace arrays where I could use "combustable trash", an XP smelter that runs cactus/bamboo all the time and a small furnace array that smelts whatever else I want to smelt. With the XP smelter, I have some redstone circuitry to make sure no bamboo is wasted and also to make sure that there is always dye in the furnace that I can take out, so I can't add another logic circuit attached to the furnace simply because I lack space. With the other smelter I'd like to have a reliable fuel supply that keeps my furnaces ready. But if the furnaces are filled with fuel and aren't smelting anything, the sorting wouldn't work.
I'm kinda afraid that this would require more redstone circuitry than a normal item sorter, since every furnace would need the logic to push items along that aren't usable as fuel
The problem is that we don't know if a furnace is low on fuel or low on input items. If it reads zero, obviously there is no fuel. But if it reads one stack, it may be one stack of fuel or one stack of input... And if we have an unlimited supply of input (say from a cactus farm), there is no redstone signal that distinguishes between 64 and 65 items.
Counting output items could be done, but that would be quite a lot of circuitry for each furnace.
can't you just point a hopper into the furnace side and put a hopper below that hopper? then do some comparator magic to slow the thing so it works properly
I haven't tested it but the Wiki says hoppers push before pulling so I'm hoping the hopper on the side of the furnace pushes if it can (if it has fuel and either the furnace is empty of fuel or has the same fuel and room in the stack) then the next hopper pulls an item from it if it has one left.
and the test of if the trash has run out would only be done once, after the last furnace and the test for if the furnaces have started to run out of fuel would be done on the output line.
It would require the furnaces be either placed in a stepwise formation requiring twice as many hoppers, an extra hopper inbetween each pair of furnaces or in double vertical rows, every other furnace to the left, every other to the right (to leave room for the hoppers removing the smelted products.)
The way I'm thinking it would work is, as long as the trash has any burnable items left they would be placed in the first furnace that has room for them, as soon as any furnace stops producing smelted items you know the trash has been depleted and stop looping it, instead sending it to your lava pit.
When the trash has been sent to destruction so the storage chest is empty the bamboo gets let through, either though the same hoppers as the trash or through hoppers on the other side of the furnaces.
At this point most of the furnaces will still be smelting but the bamboo should fill up any furnaces that have run out of trash, so the drop in production shouldn't be very large as long as you can accurately determine when the smelted output slows down.
Just testing.
I'm probably being overly optimistic about determining when the furnaces start to stop, I was thinking that could be done with a timer but I guess it would probably require a counter combined with a timer of some sort unless you're willing to wait until most of the furnaces have run out of fuel, if you're only emptying your trash a couple of times a day that might be acceptable.
It would certainly be easier to have a few furnaces set aside to process the trash though and either just accept them standing idle most of the time or wait until nearly all of them have run out of fuel (as determined by a simple timer on the smelteds output) before turning on the bamboo again.
Just testing.
No
I mean yes, but with ~30 combustible trash items and only one slot in the furnace, if an item doesn't go in then it could mean that it's not fuel or it could mean that a different item is in the furnace. And with some things burning forever (coal 80s), others really fast (bamboo 2.5s) there is no way of knowing if we need more fuel or not.
I actually have a design for auto cooker/smelter things before it goes into my sorting system that uses a dropper facing the side of the furnace with a hopper under it. when the dropper is powered it'll try to push the item into the furnace and the hopper under it is locked momentarily. However, this means that there won't be a build up of items for fuel like you're trying to do; if the furnace already has enough fuel, the items would just go straight into storage system. I do use one MIS v4.0 before the furnace to split up items that I want cooked or smelted before it's sent into the auto cooker/smelter.
I also use a system that uses the fill level of chest to control the locking/unlocking of a hopper under it for auto trashing using a comparator in subtract mode reading from that chest with another comparator pointing into the side of the first comparator that is reading the fill level of another chest. This allows me to set how filled up I want a chest to be. You might be able to set this up to toggle between which chest to use fuel from.
Didn't notice this at first reading.
It's a bit more complicated. Say hopper A goes into the side of the furnace, and hopper B is below hopper A, then any item going into hopper A would go into B and not into the furnace. The only way around this is to lock B. Then cyclically lock the hopper pointing into A and unlock C.
But that makes a build with lots of furnaces difficult: Items will go down if the furnace can't accept them, so I would need tons of elevators to move them up. Or have furnaces below each other, which isn't neat. Or am I missing something obvious?
That's why I'm hesitant to build this with extra 30 furnaces (to sort out 30 kinds of fuel). Each furnace needs the same redstone circuitry. And they would need extra redstone to control the supply of items to be smelted. (As XP farm these extra furnaces won't produce XP enough to matter. For all other stuff I don't want the item to be smelted get stuck in a furnace where perhaps no fuel comes in for weeks.
If we could push furnaces around that would be neat - just build a wildly complicated redstone circuit to handle one furnace, and switch it out every other second using a conveyer belt
I'm still not sold on the "measure smelted items" idea. Not for the XP farm where I have constant supply of cactus, because I have redstone to control that some dye is always kept in the furnace to take out, so there is no space for more redstone circuitry. (I already use 5 sides of each furnace. One to access, top for cactus, side for bamboo, back for reading the furnace, bottom for sucking dye out.) And for the other smelter there is no reliable supply of items to be smelted.
I also thought about reversing the logic: Accept items to be smelted only if the furnace has enough fuel. (Which can be done with a bit of redstone, I think.) That way, we could move the ore or whatever over all the "trash burning" furnaces first, and then have them end up at a few furnaces that have a supply of bamboo. But this doesn't solve the problem of the trash/fuel transport: Once an item gets into a hopper pointing at a furnace, the only way to get them out is by sucking them out with another hopper below. Which has to be locked with redstone to give the items time to go into the furnace, if possible. So this system would need a ton of space, and several elevators.
Still haven't gotten around to a detailled look at the multi item sorter. It's on my watch list. But so far, I doubt that our solutions are better than to to just build an extra sorter...