40d Talk:Lever

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floodgates vs. doors misinformation?[edit]

"Therefore, it is more logical to use doors, at least until doors aren't usable for holding back water."

I'm fairly certain that doors can't be closed while flooded. They work as described for opening via lever, but cannot close when blocked by water or creatures. Granted, the last time i've levered doors was back in 2d. Please verify or change the wording? --Vaevictus 15:49, 2 June 2008 (EDT)

In the current version (0.27.176.38c) doors can close if water currently occupies the same square. I believe elsewhere the wiki states this destroys the water, but I have not verified if the water is destroyed. --quartic 16:18, 2 June 2008 (EDT)
Does it matter how much water? -- Vaevictus 13:35, 3 June 2008 (EDT)
I have verified this with water of depth 1 and 7, but not values in between.--quartic 13:38, 3 June 2008 (EDT)

Todo: Check whether two levers connected to the same door operate it in the same way the older versions did - that is, pulling each lever once would open the door, then do nothing as the second lever is pulled. -- Zaratustra 19:23, 7 November 2007 (EST)

I'm using vertical bars as portcullis for my keep, and they attach to levers. Perhaps a comment that bars and grates operate identically in this version, specifically with respect to levers? -Gotthard

Doesn't the delay come from the floodgate grinding to close the water/magma channel/tunnel compared to a door slamming shut right away? --Karp 08:51, 31 October 2008 (EDT)

That is what it is meant to simulate. Like people mentioned above, though, Toady's said that doors shouldn't work as well as floodgates, so in some later version your doors will probably leak. --ThunderClaw 10:09, 31 October 2008 (EDT)

controlling at a distance[edit]

Does the lever need to be adjacent to the item it is controlling?

I want to put a floodgate at the end of a channel... GarrieIrons 02:52, 23 January 2008 (EST)

No, it can be anywhere.--Dorten 02:57, 23 January 2008 (EST)

so, analog to the support-cave-in-trap how about building a nice water basin, say 4x4 for a start and covering it with grates, all connected to a lever - do grates have to be attached to a wall or floor on one side? I will try *broad grin* --Koltom 21:45, 22 February 2008 (EST)

Grates must be attached to a wall on one side, although you can put grates next to only grates and the dwarves will build them. Followed by their collapse. Like walls off bridges.--Draco18s 18:31, 2 March 2008 (EST)
Try building supports under them. SL's hand of armok uses supports under hatches in a similar way. VengefulDonut 23:37, 2 March 2008 (EST)
Yeah, its not working like i wanted it too. The support thing will probably work. Or I will just leave a few walls in the basin..will try that later, busy right now. *watches goblin fly away in high arc* --Koltom 19:52, 3 March 2008 (EST)

Regarding remote activation/control: I just spent 10 minutes berating my dwarves for completely ignoring two Pull Lever commands while vile forces of darkness approached, only to find that once I removed the Dwarves Stay Indoors restriction, they happily stepped up to the, uh, lever. The bridges are outside, the levers are on the level below. Has anyone else experienced this? Holyfool 17:49, 22 March 2008 (EST)

Was the lever and/or any part of the path to the lever marked as "outside"? Use k to check. --Savok 10:25, 23 March 2008 (EDT)
I checked and one of the levers was indeed marked "outside". In fact, there are several squares on my first underground level that are marked "outside". Is that because they are in the general area of the stairway leading outside? Thank you for the info. --Holyfool 18:42, 29 March 2008 (EDT)
When I quit reading all new forum messages and stayed at the wiki, I thought this would stop. Read The Wiki. Really. Read it. No, really, click on that link. --Savok 19:57, 29 March 2008 (EDT)

Megabeasts[edit]

I have noticed that a bridge that a hydra is standing on cannot be retracted (0.27.176.38c). Has anyone else had similar experiences? VengefulDonut 00:15, 13 March 2008 (EDT)

Titans cause the same problem. I conjecture that bridged can't be retracted while megabeasts are standing on them. VengefulDonut 02:08, 13 March 2008 (EDT)
Also elephants, it seems. Possibly creature size. VengefulDonut 13:18, 13 March 2008 (EDT)
Dragons cause the same problem. Are megabeasts supposed to all show up at once like this? VengefulDonut 21:43, 13 March 2008 (EDT)
"All at once like this," you say? Was their a party on your bridgeworks?
And, yeah, megabeasts kill bridge operation, even "benign" acts like retracting with them on it. It must have something to do with their BUILDINGDESTROYER tag. --FJH 02:58, 6 April 2009 (UTC)
The bridge page mentions that anything with a size greater than 10 prevents the bridge from operating. --Bombcar 05:42, 3 December 2009 (UTC)

Proposed addition: Mechanism sequence[edit]

Given the problems that arise when using non magma-safe materials for mechanisms on floodgates, it is quite handy to know which mechanisms go where at the link selection (When for example you're really low on bauxite).
From my experimentation with floodgate-lever, the first mechanism selected goes at the gate and the second one at the lever. I still haven't activated the contraption, but I'm assuming it's going to be ok.
I'm also assuming the same is usefull for grates and bars. --User:Nonickch, unsigned

There is some lower-down text that tells you which mechanism goes in where. --Savok 08:30, 15 June 2008 (EDT)

Finding Links[edit]

Is it possible to determine what a lever is linked to without pulling it and checking to see what happens? -Fuzzy 00:43, 6 September 2008 (EDT)

AFAIK the only way is to attempt to link the lever to a built object and notice which one if any is not available.
eg if you have two bridges but only one is available to be linked to, it is because you are already linked to the other one.
This would be a really good feature if it was implemented.
GarrieIrons 09:55, 6 September 2008 (EDT)
I guess this is one good use for the new note-feature: Just use the same note for lever and target. --Doub 10:17, 6 September 2008 (EDT)
Right now your best way to remember what lever does what is to build a reference behind the lever as a reminder: a one-tile bridge behind the
"front door/bridge" lever, a support behind the "collapse the mountain" lever and so forth... or write down what does what on paper.
Even naming levers would be useful but for now you need the "references." -Karp 06:10, 19 December 2008 (EST)

Max number of links?[edit]

Is there a limit to the amount of objects that can be linked to a lever?--Thendash 22:56, 19 September 2008 (EDT)

Speeding the job of linking[edit]

Is it just me or does it not only take forever to finish the job of linking the lever to something, but also the dwarves treat it as extremely low priority? I've sometimes had to had an entire year for one of them to deign to hook it up. Incidentally, it is the Mechanics job that they use for that, right? -Fuzzy 15:48, 27 September 2008 (EDT)

I haven't noticed anything about the priority of the job, but yes, it take hella long to finish it. Some big linking job (eg. linking a large bridge to a remote lever) are virtually impossible to complete without an experienced mecanic... dwarves don't manage to end the job before feeling the urge to eat or drink or something, and all their work is lost when they return, ending in an infinite loop. Timst 19:47, 27 September 2008 (EDT)
Unless it's changed in the year since I've played, the mechanic must move the mechanisms to the lever and the "something", then spend time working on both the lever and the "something", all without being interrupted. Consider a 1-square stockpile next to both the lever and the something and choosing those unique mechanisms when you assign the linkage job. -- Qwip 16:42, 15 October 2008 (EDT)
The catch, so far, is figuring out the "unique" mechanisms in the list. Short of making sure that that stockpile is the only one that carries Schist Mechanisms or something similar... Unlike the other "pick an item" lists, you can't specify a sort and there's nothing zooming you to the item that you will use. On a mildly unrelated note, I realized that part of the reason for my delay was that I was building large amounts of stone traps, so the nearest mechanism that was not already tied up in a trap building job was quote some distance away. I had this problem with the nearby stockpile as well, as it was also fairly close to the traps. It would be nice to even get a distance count on the mechanisms. -Fuzzy 11:48, 16 October 2008 (EDT)
When you choose the mechanism for the lever or trap, it does tell you its distance.--Maximus 12:33, 16 October 2008 (EDT)
Addendum to Maximus's comment: When selecting the material to be used, you can expand the list of materials, and then select a particular item. Therefore, you can build a single-tile stockpile, then customize it (using q then ssettings) to only allow a certain quality mechanism. Link the lever after these stockpiles have been filled. RomeoFalling 16:21, 16 October 2008 (EDT)

Inverting a Lever[edit]

I think I found a way to automatically invert the signal of a lever, say if you wanted one lever to open one door and close another. It involves a bridge and water, so it would not be instant. I haven't tested it yet. Anyone know if it would work?

Side view: (Sorry, I realize this isn't the standard tileset, but my text editor doesn't have them all.)
#####
#_~@W
##D##

W - Water source (Under at least 7/7 pressure)
D - Water drain
_ - Pressure plate, set to activate under water of depth 4-7
@ - Hinge of a raisable bridge, connected to the main lever (offscreen)
~ - Bridge over channel
# - Solid rock

When the main lever is OFF, the bridge is down. It allows water to flow past its hinge, and it covers the drain. Water fills the room, triggering the plate, which sends an ON signal.
When the main lever is ON, the bridge raises. The hinge blocks water from flowing in, and the uncovered drain empties the room. The plate detriggers, sending OFF.
WARNING: The drain must not fill! If it does, you wont be able to get into the room to connect more mechanisms to the plate. Option: If your water source is infinite, make your drain a hallway, at least 3 long, with a raising bridge that comes down from the far end. When the main lever is activated, the hallway floods. Shortly afterwards, the plate detriggers. After a short delay, the bridge slams down, destroying the water.
--17:52, 1 October 2008 (EDT)

Isn't it simpler to build two levers? Especially considering the pressure plate takes as many mechanisms? I don't really understand what you are trying to accomplish here.
--MagicGuigz 17:34, 15 October 2008 (EDT)
If you want a single action to do some "on" actions and some "off" actions - e.g. if from a stylistic point of view you want to have a single "activate outer defenses" lever that raises bridges over moats and puts down bridges blocking catapults.
--Random832 19:35, 15 October 2008 (EDT)
It's more than stylistic. My designs are complex systems, created on the assumption that only certain combinations of states are possible - that when this bridge is down, that bridge is always up, and that when this floodgate is open, that door is always closed. If I allow things to enter a condition I hadn't planned for - either because I forgot to throw both leavers, or the dwarf died between them, or whatever - there is literally no telling what would happen. It could drop civilians into a line of fire, or flood the fortress, or expose the marksdwarves to the enemy without also releasing their infantry guards.
--Macdjord 16:08, 16 October 2008 (EDT)
I'd say you should consult the Computing and Mechanical Logic pages then. Should find all the components you need there.
--Bilkinson 16:13, 16 October 2008 (EDT)
Doesn't help. That's all about power transfer - gears, axels, waterwheels... It only uses levers for input, not output - I could connect my controll leaver to a not-gate like this one, but how do i connect that to a bridge?
--Macdjord 17:17, 16 October 2008 (EDT)
Connect that power to a screw pump, that pours water onto a pressure plate. There's an example of such a device on the mechanics page. Take a look as Water/Fluid logic as well (Linked to on the mechanical page) for some other pump-based devices.
--Bilkinson 06:56, 17 October 2008 (EDT)
It's... workable, I suppose. It's much more complex than the bridge system. It might be faster responding, depending on the speed at which a pump works, since there is no 100 step delay like a bridge. It would take a lot more room and mechanisms, not to mention a seperate power source for each one. Remember, each leaver you invert need its own, independent setup.
--Macdjord 13:09, 17 October 2008 (EDT)
Check out this page, it might help.. www.dwarffortresswiki.net/index.php/User:SL/Logic_Gates.
Martinuzz 8:54, 28 October 2008 (EDT)
So the goal here is to have water on a pressure plate when a lever is set to ON. Don't hatch covers respond quicker than bridges?
Gee, this sucks. I thought things just toggled whenever you flipped the lever. That's how it should be IMHO. Gairabad 20:31, 13 November 2008 (EST)
Side view:

####
#^HW
##D#

^ = Pressure Plate
W - Water Inlet
D - Drain
H - Hatch Cover
# - Solid rock
Main lever linked to Hatch Cover (H). When the lever is OFF, the hatch is closed and the Pressure Plate (^) chamber fills. When the lever is ON, the Hatch Cover (H) disappears and water drains away before reaching the pressure plate ledge.
Wangcommander 01:27, 12 November 2008 (EST)
But since you're not actually blocking off the water, you are dependent on the fickleness of the water pressure simulation. Sure, the room would never fill with an open hatch between the water source and the hatch, but after the first use it starts off filled. Are you certain it will drain? If the water comes in from the source as fast as it goes out the drain, will it not stay full? That's the advantage of using the bridge - it is the only piece of equipment that blocks water in the ON position.
A hybrid design might be useful, using a bridge to block the input bu a hatch to control the output. When you switch it, the hatch instantly starts draining the water, then the bridge seals the inlet 100 ticks later to guarantee a complete drain.
--Macdjord 16:04, 12 November 2008 (EST)

I might be misunderstanding the goal of this (and, for the record, I do think it's really cool), but wouldn't hooking up the lever to the thing you want non-inverted, then flipping the switch, and then hooking it up to the inverted thing accomplish the same thing? That way you have two things hooked up to the lever that are in opposite states of each other..... Zardus 05:09, 26 February 2009 (EST)

A 'Pull the lever' task is not a logical toggle. It toggles the lever, and then activates the lever to signal its current state to its linkages... That is, if the lever is in the 'open' position, pulling it flips it to 'closed' and then sends 'closed' to all its linked buildings. Anything which is, for whatever reason, currently in the 'closed' state will simply remain closed. The case you describe is such a situation. It can also arise where a lever is pulled twice in less time than it takes for the first signal to produce its effect. That is: A dwarf pulls a lever linked to a bridge. The dwarf takes 2 steps away, pauses to decide what to do, and notices that there's a pull the lever task on a lever 2 steps away. The dwarf returns to pull the lever again. The bridge has not yet raised when the second signal is sent... A little bit later, the bridge will raise, but unless the lever is pulled again, to get it into the 'raise' state, and then a fourth time to get it to the 'lower' state, the bridge will not lower.--wattj 11:03, 26 February 2009 (EST)

Something like this? http://dwarf.lendemaindeveille.com/images/4/48/LeverInvert.gif --Grek

how to disconnect levers?[edit]

Is there a way to disconnect a lever from an object without destroying the lever and rebuilding it? --Shaver 12:53, 2 January 2009 (EST)

You can't, to my knowledge. Mechanisms in a lever and the connections stay in place until the lever is deconstructed. I use a lever for cage traps in an arena, and after every 'round' I need to rebuild it to get back the mechanisms I used. --Eddie 14:17, 2 January 2009 (EST)
You could deconstruct the object :) --Adeptable 07:47, 9 September 2009 (UTC)

See what's connected to a lever?[edit]

Is there a way to see what's connected to a lever? I've lost track of which lever does what, and I'd prefer to not randomly set off my traps trying each one out. --Katt 00:15, 3 March 2009 (EST)

No. This is why its a good idea to keep levers proximal to objects they connect to. I also try to color code levers to the object and gears used for the connection. --Squirrelloid 01:36, 3 March 2009 (EST)

You can also use the Notes thing to label them. --LegacyCWAL 17:15, 3 March 2009 (EST)

Mystery levers have historically been a great source of fun. Especially in bloodline games. --Jellyfishgreen 10:16, 4 June 2009 (UTC)

Multiple connections for the same lever/object pair[edit]

I've just removed the text:

A lever can be linked more than once to the same object - this has no effect except to consume more pairs of mechanisms.

because I don't experience this in 0.28.181.40d15

--Adeptable 17:34, 6 September 2009 (UTC)

Confirmed - partly. Once a lever is successfully linked(but NOT when the linkage is in queue), that item will no longer appear in the lever's list of things that can be linked. Might need to confirm what happens if you queue the same object twice. I think the second link job spits out an error when the queue reaches it but I'm not sure. --Shurhaian
Hmm, I just tried queuing the same link (lever to door) twice. Both links were made, and now the door contains two mechanisms. So it is possible... I'll add this back to the article with some explanation. --Adeptable 20:01, 9 September 2009 (UTC)