|This article is about an older version of DF.
A lever is a mechanism that has been constructed on the floor. Once in place, it can be linked to one or more other devices such as doors, bridges or supports, permitting you to control these other devices by ordering the lever pulled through its menu.
Levers do not block movement. Levers are counted as furniture for created wealth of a fortress.
A lever can be limited to who can pull it, similar to a workshop, in the rofile for that lever. (This can be handy for a variety of special purposes.)
Either a lever or a pressure plate, once linked to one or more devices (doors, traps, or whatever), can act as a trigger, an activation mechanism for that secondary system. The two are activated differently, but the connected system is activated just the same. One system can have more than one trigger linked to it, and one trigger can be linked to more than one system.
Placing a lever
If you have a spare mechanism, you can designate the new lever job via the "uild - Traps/Levers - ever" keys. Mechanism quality has no known effect on the performance of the lever. Low-quality mechanisms work fine, but since they are counted as furniture, high quality mechanisms give more created wealth.
Once a mechanism has been placed as a lever, it then requires a pair of mechanisms to link that lever to any object, regardless of distance or size, and quality of the mechanism makes no reported difference. This is done by giving the lever the appropriate job order via (similar to any workshop), selecting what sort of object you want the lever linked to*, and then using the and keys to scroll through the available examples of those and selecting the one you want. The list is chronological, with the last object finished listed last, and the map will re-center on the exact object as you scroll.
A lever can be connected to any number of objects at the same time, but, as each linking is a job designated at that lever, only one linking job will be tasked at any one time - after that job is finished, the next will begin. (That is, if you want one lever connected to 101 different doors, cages, bridges and supports, you can do that, but those jobs will not occur simultaneously.) Up to 10 linking jobs can be queued up at any one time on one lever, the same as with jobs at any workshop.
Once a link is completed (not queued), the target will no longer appear in the lever's target list. However, if you queue the same linkage twice then both tasks will be performed. This has no effect other than to use up more mechanisms.
Once linked, a trigger can only be de-linked by deconstructing the trigger itself or the target. By doing so you will recover the linking mechanism used on that side. To get both back you will need to deconstruct both the trigger and the target. Deconstructing a linked object has no effect on other objects linked to the same lever; deconstructing a lever unlinks all objects linked to it. If you wish to relink an object to the same lever, you must use two new mechanisms - you cannot "re-use" the mechanism still in the lever without deconstructing that, too, and starting over entirely. Note that this may not be feasible when dealing with floodgates, as they leave a channel behind when deconstructed, preventing a new floodgate from being placed in the same location.
A lever is activated (or "pulled") through its menu with via the "dd new task ull" keys, which establishes a new job that then needs to be filled. An idle dwarf will then come to pull the lever - no labor need be designated for this task, so any adult civilian dwarf might volunteer, and from anywhere on the map that has a path to that lever at the time, though in most cases the nearest dwarf will be chosen.
Note that once the actual lever is pulled, any attached objects may take more time to respond - see below.
Specific Response Levers
Some lever systems are intentionally designed to be pulled only by specific dwarves. By limiting which dwarf/dwarves can respond to an order to "ull Lever" (via that lever's workshop profile), you can control who responds, which specific dwarf pulls that lever. This means you can largely control who will be standing "right there" when that lever activates... whatever.
This can be used for...
- Limiting general lever pulling to haulers and other relatively useless dwarves.
- Retiring unwanted nobles or other dwarves.
- Locking a dwarf behind a door - for instance, locking a mason or stone crafter in with a particular stone to force them, and only them, to work with it.
- Sealing an otherwise relatively useless dwarf in a lever control room.
- Choosing a sacrificial dwarf for a suicide lever pulling mission.
On/Off vs Open/Close
Levers normally have an "on" and an "off" state, seen as whether the small tag at the top of the lever is to the left ("off" state) or the right ("on" state). Upon being pulled, the state of the lever changes, and everything they're connected to updates to the corresponding state of that lever, and does not just change states ("toggle"). This becomes important if you have several levers attached to the same device, or one trigger attached to several systems.
- Example: 2 levers (both in "off" position) are connected to a drawbridge. After pulling the first lever, the bridge will lift. Pulling the second lever tells the bridge to "open", which it already has done - no visible effect. When it is pulled a second time it will let the bridge down. This in turn requires the first lever (still in "open/lift" position) to be pulled twice to trigger a change (lift again), and so on.
"On" and "off" state is fixed and dependent on the lever, not the object that lever is linked to:
- "dash to the right" ( ó ) is on
- "dash to the left" ( ò ) is off
Floodgates and bridges have a delayed response to all incoming signals, and will not respond to subsequent signals until the first has taken effect. For instance, if you pull a lever attached to a floodgate on then off in rapid succession, the floodgate will only respond to the first signal, independent of the position the lever rests in eventually.
Objects that can be controlled by levers include:
A "step" is not a step that a dwarf makes, but one "step" that the game advances. When paused (via ), you can manually advance the game "1 step" by hitting the period ( ) key. When unpaused, your FPS equals the number of "steps" that happen per second.
- Bridge – Activates 100 steps after being triggered
- On: Turns the bridge into either a raised drawbridge, or a retracted bridge, depending on which option was chosen when the the bridge was constructed.
- Off: Returns the bridge to normal.
- Door – Activates instantly. Note that once you connect a door, it is either completely open or sealed shut. There is no "closed, but can be opened by a dwarf" state anymore.
- On: Opens the door.
- Off: Closes the door.
- Floodgate – Activates 100 steps after being triggered.
- On: Opens the floodgate.
- Off: Closes the floodgate.
These items, when activated, deconstruct, and/or cannot be triggered again until re-linked.
- Cage – Deconstructs the cage and releases all of its contents. The cage and its attached mechanism will be left on the floor nearby; you recover the mechanism used on the cage but you do not recover the mechanism used in the lever until you deconstruct the lever itself.
- Restraint – Deconstructs the chain/rope and releases whatever creature it held. The restraint's mechanism will be left on the floor nearby, and the restraint itself will remain attached to the creature's neck; again, you recover the mechanism used on the restraint but you do not recover the mechanism used in the lever until deconstructing the lever itself.
- Support – Deconstructs the support, ideally without a dwarf next to it. Most commonly used to cause controlled cave-ins. The support's building material and its attached mechanism can both be recovered (unless they happen to get destroyed in said cave-in).
Some players prefer to create a "control room" and lock a dwarf in when they expect to need quick response to their levers, to avoid long delays. A control room is an area where important levers are located. It often has doors on all entrances, so a dwarf (or more than one) can be locked inside to guarantee that one nearby dwarf will be idle who can pull a lever at a moment's notice, rather than wait for the first idle dwarf to respond, who might be far across the map. This can be critical with some of the more complex trap designs. For longer sieges, a small personal stockpile of booze and food is critical, or an "airlock" that can be (re)stocked for prolonged situations.
Some control rooms have all doors linked to a single lever, which is the first one pulled - this seals in the first volunteer to respond, although ctivating a specific recruit and stationing them and then manually locking them in the control room is sometimes faster. Double doors, one set manual, and one set linked, allow for manual sealing of the room in either manner. (It's advised to have a backup lever somewhere to open the linked doors in case of accidents.)
Advanced players do not trust doors alone to protect their control room, as some fortress invaders are building destroyers, and can deconstruct any door or floodgate they come across.
Because control rooms often contain levers linked to most every important system in the fortress, it's critical to guard it against troublemakers like gremlins and tantruming dwarves. Having wardogs or other attack animals chained at all entrances is a good start, and military stationed nearby is popular as well.
Because of the crowded nature of a control room, it's particularly important to label your levers and/or organize them for positive identification as to function. Returning to a game after a week and not remembering which lever releases the magma or shuts the main gate is too much fun for some players.
There is no way to determine what levers operate what objects except by pulling them and seeing what happens.* Because of this, it can be critical to, somehow, keep track of what lever does what and where (especially in a control room!). Some players may simply write them down on a notepad, use architecture to help label their levers (either placing them near the objects they activate, or in small bays organized in groups, even within a control room), or even construct a letter or symbol in a floor mosaic - whatever works, so long as it does work.
- (*): Not exactly true. You can attempt to link the lever to a new object. Anything already linked to that lever will not show up in the list, as an existing link cannot be duplicated. So you could, in theory, look through the entire list; any item which doesn't appear in that list is linked. However, this process of elimination becomes a very daunting prospect with, say, doors.
Note that while a thief can bypass a "locked" door, any barrier linked to a mechanism and in the "closed" position is impassable to any creature. However, some creatures have the building destroyer tag, and can deconstruct the barrier entirely if they can reach it.
The easiest way to do this is to build a number of unlinked levers, so pulling them does not cause trouble in your fortress, and then to assign profiles to the levers so only the right dwarves pull them. In most cases the profile will just be all your hauler dwarves as other jobs seem to generate plenty of income.