40d:Lever

A lever is a device that can be linked to other devices to control them through it's q menu once the controlled device is constructed. It needs one mechanism to be constructed (if you have a mechanism, you can build the lever with bTl). A lever is pulled through its q menu with aP. A nearby dwarf will then pull it. Pressure plates are like levers, but are activated automatically by creatures stepping on it.

Levers have an 'on' and a 'off' state. Upon being flipped, everything they're connected to updates to the lever's new state. This becomes important if you have several levers attached to the same building.

Several devices, such as 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 'on' (open) signal.

Objects that can be controlled by levers include:

Multiple Uses

• Bridge
  • 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 – Note that once you connect a door, it is either completely open, or locked. There is no "closed, but can be opened by a dwarf" state anymore.
  • On: Opens the door.
  • Off: Closes the door.

• Floodgate – After the lever is installed, it works exactly like a door.
  • On: Opens the floodgate.
  • Off: Closes the floodgate.

• Hatch – When open it just disappears and allows water through. Note it is suspected that like doors - once you connect a hatch, it is either completely open, or locked.
  • On: Opens the hatch.
  • Off: Closes the hatch.

• Grate – When it is open, it just disappears. Water goes through it just the same, but it cannot be walked on anymore. Anybody on it will probably fall through^[Verify].
  • On: Opens the grate.
  • Off: Closes the grate.

• Bars – When it is open, it just disappears. Water goes through it just the same, but it cannot be walked on anymore. Anybody on it will probably fall through^[Verify].
  • On: Opens the grate.
  • Off: Closes the grate.

• Upright Spear/Spikes
  • On: Retracts spears/spikes.^[Verify]
  • Off: Extends spears/spikes.^[Verify]

• Gear assembly – When it is disengaged, no power goes through it and anything that is being kept up by its presence (like a windmill right on top of it) falls down.
  • On: Disengages the gear assembly.
  • Off: Engages the gear assembly.

One-Shot

• Cage/Restraint – Opens the cage/chain/rope and releases whatever it held. This is permanent and you will have to reinstall and relink the cages/restraints after one use. You recover the mechanism used in the cage/restraint.

• Support – Deconstructs the support, except without a dwarf next to it. Most commonly used to cause cave-ins.

Computing

Elaborate combinations of levers (or pressure plates) and other objects can be used to create mechanical systems that can perform various forms of computing.

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