v0.31:Pressure plate

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v50.12 · v0.47 · v0.34 · v0.31.25 · v0.28 · v0.23 This article is about an older version of DF. More Info · V

Pressure plates act in similar ways to levers, in that they require mechanisms to be built, and then a pair of mechanisms to be linked to a floodgate, spike trap, bridge, or what-have-you. Their accompanying activity is triggered the instant a creature has stepped on them (not including the delay associated with the triggered item); leave a time delay space for traps based on enemy movement

Types

One-use pressure plates send their signal, then deconstruct the first time they're triggered, leaving behind the mechanism used to construct them and destroying any mechanisms used to link them to other objects. As such, use low quality mechanisms to link with these.

Resetting pressure plates can be reused as many times as you want. They disengage 100 ticks after their trigger is removed.

Uses

Pressure plates are used as a variety of triggers for other activities, such as bridge raising or defensive and trap purposes, such as magma or water traps involving reservoirs of said substances.

Pressure plates send an 'open' command the instant something steps on them, and a 'close' command about 100 ticks after something steps off of them. If a pressure plate sends an 'open' command to a door/floodgate/floor hatch that is already opened, nothing happens. The only exception to this is gear assemblies, which toggle their engaged/disengaged state on every trigger from a lever or pressure plate.

Advanced Techniques

Making complicated devices with pressure plates requires a full and detailed understanding of how pressure plates function.

Resetting pressure plates send two signals: an on signal, when first triggered by an appropriate creature or fluid; and an off signal, set to occur about 100 ticks after the pressure criteria are no longer met. They do not send continuous on signals while the pressure criteria are met. A pressure plate that is untriggered then retriggered before it has sent an off signal will not send an on signal on the second trigger, and will abort the off signal scheduled to occur from the untriggering.

Special care must be taken when linking multiple pressure plates to a single device. When doing so, it's possible for one of the plates to become activated before another plate has sent an off signal. Unlike with single plates, the triggering of the first plate will not abort the off signal scheduled from the second plate, and the triggered device can become deactivated (closed) despite a triggered pressure plate linked to the device.

Another essential consideration with carefully timed devices is build order. Pressure plates can send on and off signals at different times depending on what sort of building is being triggered and whether the building was built before or after the pressure plate.

• Linked doors and hatches always open the same tick that a pressure plate is triggered, but close depending on build order: if built before the pressure plate, they close 99 ticks after the trigger is removed, and if built after, they close 100 ticks after the trigger is removed.
• Retracting spikes built before a pressure plate retract 40 ticks after triggering and extend 139 ticks after the trigger is removed. If built after the triggering pressure plate, they retract 41 ticks after triggering and extend 140 ticks after the trigger is removed.
• Gear assemblies are unaffected by build order. They always toggle on the tick that a pressure plate is triggered and 99 ticks after the trigger is removed.
• Bridges, vertical bars, floodgates, and grates built before a pressure plate open 100 ticks after the trigger is sent, and close 199 ticks after the trigger is removed. If they are built after a triggering pressure plate, they open 101 ticks after a trigger is sent and close 200 ticks after the trigger is removed.

Essentially, pressure plates send open signals immediately upon triggering and close signals 99 ticks after their trigger is removed; pressure plates built before the device they trigger work a tick later; and doors and hatches are always opened on the exact tick that they're triggered by a pressure plate, regardless of build order, although their close tick is affected by build order.

Latching Pressure Plates

Resettable Latching Plate System.
Uses scaffolding (not shown) just like a pump stack.

While ordinary one-use plates are easy to use, they deconstruct immediately after triggering and destroy all but one of the mechanisms used. Sometimes, it's desirable to have a system that triggers once, then waits to be reset manually. For example, you might have a pressure plate that seals off your entrance and floods it with magma, but you don't want the flood to stop or the drawbridges to open like it would for a resetting pressure plate, but you also don't want to rebuild and reconnect the one-use pressure plate after every siege when half the parts are submerged in magma. This is when you should use a more complex setup like the one shown in the picture to the right.

Suppose you want to use a pressure plate to seal off your main entrance. You build the setup shown, being sure to construct the lower pumps before the upper pumps and the gear assembly on top after both pumps are done. Then connect the plate in room 2 to the drawbridges that seal the entrance and hook a resetting, enemy triggered plate from your main hallway to the hatch in room 1. The resetting pressure plate in room 2 should be set to trigger whenever any water is on it. You also connect a lever to the gear assembly above the pumps, which becomes your reset lever, and pull the lever to disengage the gear once its set up. You also connect that gear to a power source with at least 25 power. Lastly, you fill area 1 with 7/7 water (to prevent evaporation) by channeling through the floor and designating a pond zone above it. After it's full, remove the pond zone and build a floor over it for good measure. During construction, you will need scaffolding just like what you use for a pump stack. This setup uses the same trick of channeling through the floor and building the lower pump first to allow them to share their power source. Remember to forbid the access doors when you're done setting everything up.

You can power this from any source, but if your map gives 40 wind power you can just use a windmill. Build a windmill right above where it says "power here" and then build a gear assembly directly below it. Putting a windmill directly on top of a gear you disengage can cause the windmill to collapse, so don't try that unless it says the windmill has a stable foundation. You may also want to construct a wall around your windmill to prevent a building destroyer from smashing it.

Now, whenever your pressure plate is triggered, the hatch will immediately open and dump the water from 1 onto the plate at 2, holding that plate down until you use your reset lever to activate the pump and put the water back on top of the hatch. Don't forget to turn the pumps off after all the water has moved, or it will continue to reset itself until the pumps are stopped. You can eliminate that minor problem by hooking the pressure plates in the Toggle System to the gear assembly on top of the pumps instead of a lever, but that's significantly more complex.

Construction

Pressure plates are built on any floor using b, T, p. You will be prompted to enable what type of things should trigger the plate (water, magma, creatures, or some combination of the three). You are then instructed to set up a range between two values of weights- a minimum to a maximum. e and r affect the minimum weight, and d and f affect the maximum. Check the table below for information related to weights.

The number of mechanisms required to build a pressure plate depends on how many types of things (water, magma and/or creatures) can trigger it. If only one of them can trigger it, it takes one mechanism. If two can (water and magma, water and creatures, or magma and creatures) then it takes two mechanisms. If all three can trigger it, it will take 3 mechanisms.

NOTE: The creature selection screen has an additional setting that allows the pressure plate to ignore, or be triggered by, your citizens. "Citizens" appears to include merchants, diplomats and tame animals.

Construction is done by a mechanic, who will require one to three mechanism. After construction is completed, use the q key to view the building, and press a to link the pressure plate to choose which trap, floodgate, or other device will be triggered by it. Your mechanic will haul one mechanism to the desired device, work for awhile, and then take another mechanism to the pressure plate itself and complete the task. Your pressure plate is now ready for action.

Choosing Weights

Only adult weights appear in-game. Children creatures will still trigger pads, even though they are unlisted. Creatures with the TRAPAVOID token will not trigger pressure plates, regardless of weight.

First of all, numbers are only showing their first four most significant digits; 500,000, the default minimum weight, will appear to be 5000 in-game. It is easy to double check what you want to set it to by using a lookup and reverse lookup on the list, to compare what the game says about a creature, and what the list says.

Secondly, The weight settings are set up in what appears to be an odd way, but makes sense for the large scale of numbers we can work with. e or d will decrease the weight by 10,000, and r or f will increase the weight by 100,000. It is slightly clumsy but it would be annoying to increase digits by units of 10,000 when trying to get from crundles to whales.

Finally, it appears the weights of creatures between 1,000 and 10,000 in the game have been conglomerated into the 10,000 minimum weight. (Crundles, who weigh 1,000, are listed in the same category as gremlins, who weigh 10,000) The maximum weight is also inclusive of everything over 2,000,000 to at least 20,000,000, until someone verifies that fully grown dragons (over 1000 years old) set off a plate set to "Max (any)".

Weight List

Use your browser's "find" function to easily search for creatures.

[A] following a creature name means it is an Adult, typically 2-12 years after birth; 2 for most work or wild animals, 12 for standard creatures.

[C] means that it is the Child weight, usually one year after birth. Careful, some creatures, most notably Dragons, are newborn/children for 1000 years after birth- there is a weight at age 0 and an increase at age 1000.

Newborn weights are not listed here as it is extremely unlikely they would ever be useful, except for perhaps sentient creatures such as dwarves and humans. On that note, Dwarves, Elves, Humans, and Goblins have separate entries for each stage of life- they are in all caps.

Vermin inherently do not trigger traps - aside from their weight being consistently less than 1000, they aren't treated as actual creatures for the purpose of triggering any sort of trap.

Weight	Animals
1,000 (Minimum)	Groundhogs[C], Stingrays[C], Buzzards[A], Crundles[C], Creepy Crawlers, Two-Legged Rhino Lizards, Knuckle Worms, Cave Fish, Cave Fish Men, Fire Snakes
2,000	Gremlins[C], Cats[C], Rhesus Macaques[C], Magma Crabs[C], Hungry Head[C], Helmet Snakes[C], Fox Squirrels, Fluffy Wamblers
3,000	DWARVEN BABIES, ELVEN BABIES, Foxes[C], Raccoon[C], White Handed Gibbons[C], Black Handed Gibbons[C], Gray Gibbons[C], Silvery Gibbons[C], Pileated Gibbons[C], Bilou Gibbons[C], White Browed Gibbons[C], Black Crested gibbons[C], Angel Sharks[C]
4,000	HUMAN BABIES, Groundhogs[A], Vultures[C], Milkfish[C]
5,000	Kobolds[C], Cats[A], Hoary Marmots[C], Rhesus Macaques[A], Hungry Head[A], Bugbats[C], Stingrays[A], Bluefish[C], Amphibian Men[C]
6,000	Foxes[A], Siamangs[C], White Handed Gibbons[C], Black Handed Gibbons[C], Gray Gibbons[A], Silvery Gibbons[A], Pileated Gibbons[A], Bilou Gibbons[A], White Browed Gibbons[A], Black Crested Gibbons[A], Sea Lampreys[C], Blacktip Reef Sharks[C], whitetip Reef Sharks[C], Fire Imps
7,000	Mountain Gnomes[C], Dark Gnomes[C], Raccoon[A]
8,000	Spotted Wobble, Shortfin Mako, Longfin Mako, Coelacanth, Orangutans
10,000	Gremlins[A], Ice Wolves[C], Mountain Goats[C], Hoary Marmots[A], Gazelles[C], Mandrills[C], Crundles[A], Bugbats[A], Gorlak[C], Plump Helmet Men[C], Spiny Dogfish Sharks[C], Milkfish[A], Longnose Gar[C], Reptile Men[C], Serpent Men[C]
12,000	Dogs[C], Siamangs[A], Molemarians[C], Snailmen[C], Slugmen[C], Leechmen[C], Large Rats[C], Wagons
15,000	DWARVEN CHILDREN, ELVEN CHILDREN, GOBLIN CHILDREN, Mountain Gnomes[A], Dark Gnomes[A], Pond Grabbers[C],Reachers[C], Blacktip Reef Sharks[A], Whitetip Reef Sharks[A], Angel Sharks[A], Bluefish[A], Pike[C]
17,000	HUMAN CHILDREN
20,000	Kobolds[A], Wolves[C], Gazelle[A], Mandrills[A], Floating Guts, Drunian[C], Creeping Eye, Green Devourers[C], Maneras[C], Cave Blobs, Frill Sharks[C], Conger Eels[C], Cod[C], Great Barracuda[C], Longnose Gar[A], Carp[C], Sea Lampreys[A], Merpeople[C], Amphibian Men[A], Ant Men Workers, Ant Men Drone
25,000	Leopards[C], Cheetahs[C], Chimpanzees[C], Bonobos[C], Tigerfish[C], Large Rat[A]
30,000	Satyrs[C], Dogs[A], Cougars[C], magma Crabs[A], Foul Blendecs[C], Pond Grabbers[A], Spiny Dogfish Sharks[A], Spotted Wobbegong Shark[C], Mako Shortfin Sharks[C], Mako Longfin Sharks[C], Common Fish Skates[C], Coelacanth[C], Naked Mole Dogs[C], Troglodyte[C]
35,000	Pike[A]
40,000	Stranglers, Wolves[A], Jaguars[C], Orangutans[C], Cave Floaters, Carp[A]
50,000	Trolls[C], Minotaurs[C], Ice Wolf[A], Beak Dogs[C], Mountain Goats[A], Giant Eagles[C], Warthogs[C], Leopards[A], Cheetahs[A], Chimpanzees[A], Bonobos[A], Drunians[A], Elk Birds[C], Snake Helmets[A], Gorlak[A], Plump Helmet Men[A], Snailmen[A], Slugmen[A], Leechmen[A], Giant Leopards[C], Giant Cheetahs[C], Basking Sharks[C], Bull Sharks[C], Conger Eels[A], Cod[A], Tigerfish[A], Giant Bats[C], Giant Rats[C], Giant Cave Spiders[C], Giant Cave Swallow Men[C], Reptile Men[A], Serpent Men[A], Ant Men Soldiers
60,000	DWARVES, ELVES, GOBLINS, Satyrs[A], Foul Blendec[A], Harpies, Black Bears[C], Cougars[A], Maneras[A], Tigermen[C], Frill Sharks[A], Great Barracuda[A], Naked Mole Dogs[A], Troglodytes[A]
70,000	HUMANS, Grimelings, Deer[C], Flesh Balls, Green Devourers[A], Blood Men, Reachers[A], Gabbro Men, Amethyst Men, Merpeople[A], Fire Men, Magma Men, Iron Men, Mud Men
75,000	Jaguars[A], Gorillas[C]
80,000	Orangutans[A], Giant Jaguars[C], Spotted Wobbegong Shark[A], Mako Shortfin Shark[A], Mako Longfin Shark[A], Coelacanth[A], Halibut[C]
90,000	Molemarians[A]
100,000	Yeti[C], Sasquatch[C], Donkey[C], Giant Eagles [A], Grizzly Bears[C], Warthogs[A], Lions[C], Tigers[C], Elk birds[A], Draltha[C], Blind Cave Bears[C], Giant Leopards[A], Giant Cheetahs[A], Giant Desert Scorpion[C], Blue Sharks[C], Common Fish Skate[A], Opah[C], Giant Bats[A], Giant Rats[A], Giant Moles[C], Giant Cave Spiders[A], Giant Cave Swallow Men[A]
120,000	Werewolves, Nightwings, Black Bears[A], Muskox[C], Tigermen[A]
140,000	Deer[A]
150,000	Beak Dogs[A], Mules[C], Gorillas[A], Elk[C], Cave Dragons[C], Giant Jaguars, Basking Sharks[A], Bull Sharks[A], Giant Toads[C], Giant Olms[C]
200,000	Dragons[C], Hydras[C], Horses[C], Grizzly Bears [A], Alligators[C], Lions[A], Polar Bears[C], Blind Cave Bears[A], Giant Lions[C], Giant Tigers[C], , Giant Desert Scorpion[A], Tiger Sharks[C], Hammerhead Sharks[C], Opah[A], Giant Groupers[C], Swordfish[C], Halibut[A], Bluefin Tuna[C], Sea Serpent[C], Giant Moles[A], Ant Men Queen
220,000	Great White Sharks, Whales, Basking Sharks, Manta Rays
225,000	Tigers[A]
250,000	Trolls[A], Cows[C], 1 Humped Camels[C], 2 Humped Camels[C]
285,000	Muskox[A]
300,000	Unicorns[C], Yeti[A], Sasquatches[A], Blizzard Men, Donkey[A], Elk[A], Blue Sharks[A], Sturgeon[C], Marlins[C], Cave Crocodiles[C], Giant Toads[A], Giant Olms[A]
400,000	Mules[A], Alligators[A], Saltwater Crocodiles[C], Polar Bears[A], Voracious Cave Crawler[C], Giant Lions[A], Ocean Sunfish[C]
450,000	Giant Tigers[A]
500,000 (Default Minimum)	Horses[A], 1 Humped Camels[A], 2 Humped Camels[A], Great White Sharks[C], Tiger Sharks[A], Hammerhead Sharks[A], Manta Rays[C]
600,000	Unicorns[A], Cows[A], Giant Groupers[A], Bluefin Tuna[A], Cave Crocodiles[A]
650,000	Swordfish[A]
750,000	Walrus[C], Hippo[C]
800,000	Marlins[A], Saltwater Crocodiles[A]
900,000	Voracious Cave Crawler[A]
1,000,000	Whale Shark[C], Ocean Sunfish[A]
1,500,000	Rutherer[C], Walrus[A], Sturgeon[A], Hippo[A]
2,000,000	Ogres[C], Ettin[C], Cyclopes[C], Jabberer[C], Great White Sharks[A]
2,300,000	Manta Rays[A]
2,500,000	Elephants[C], Blind Cave Ogres[C], Draltha[A]
3,000,000	Giants[C], Rutherer[A]
4,500,000	Jabberer[A]
5,000,000	Elephants[A], Basking Sharks[C]
6,000,000	Ogres[A]
7,000,000	Blind Cave Ogres[A]
8,000,000	Cyclopes[A], Ettin[A], Hydras[A], Sea Monsters
9,000,000	Giants[A], Sea Serpents[A]
10,000,000	Whales[C]
15,000,000	Cave Dragons[A], Basking Sharks[A]
20,000,000	Bronze Colossuses, Whales[A], Whale Sharks[A]
25,000,000	Dragons[A]

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