I've been lurking on these boards for a long time, but this is the first time I've posted. Why? Well, I finally built something I'm proud of.
Ladies and Gentledwarves, I submit to you, the Automatically Resetting Ice Trap:
http://mkv25.net/dfma/movie-2239-automaticresettingicetrapThe idea was simple. I wanted to build a trap which froze enemies in a block of ice, then used magma to melt the ice and reset the trap. The execution of that idea was not.
The first problem was coming up with a design for The Device (it still needs a decent name). After sketching a few plans out on paper, I found one which I thought should work. I did a little experimentation in a junk fort, couldn't find any obvious flaws and decided to build the real thing.
The second hurdle was trying to find an appropriate site. Obviously, it had to be in a freezing biome. I knew I would need a lot of pumps (my rough design called for 4 pumps for each tile that freezes). I knew I would need power to run those pumps. I knew I would need magma, underground water and materials to make the pumps out of. From those criteria, I decided a 40d fortress with an underground river, magma vent and sand would suite my needs (Glass is mostly magma proof in 40d, and I wasn't sure about being able to generate enough power in a 0.31.XX fort from windmills, nor did I want to pump magma up a bunch of levels). I also *wanted* flux and a sedimentary layer for bauxite but finding such a perfect site in 40d was too much. In time, I found a suitable but not ideal location and set out to build The Device, bringing along lots of lumber and some bauxite. There was no sedimentary layer, but it had everything I needed plus marble and some Fun Stuff. Honestly, finding the right place to build was the hardest part of this adventure. In retrospect, maybe I should have used 0.31.XX
The video above is fun to watch but there is a lot going on behind the scenes. I'll be using screenshots of The Device while it was still under construction
for the long boring explanation to explain how it works. These are all from on of my seasonal backup saves, just before I filled The Device with water and magma.
Here is a shot of the main hallway, where all the action takes place. Note that at this point in the construction, The Device hasn't been opened up to the outside world yet. Latter on I dug a set of stairs at the eastern end of the hallway to allow enemies to enter.
When an enemy steps on the pressure plate near the left end of the hallway, it opens the hatch covers you see to the north of the pumps (all of these pumps take water from the north side and push it south). Once the hatches are open, the pumps push water through the fortifications into the main hallway. The floors above the hallway have been channeled out so any water which enters this area freezes instantly, killing the enemy.
Note the second pressure plate at the east end of the hallway. This one is set to trigger where there is depth 3 or greater water on it's tile. There is only a diagonal connection to the fortification south west of the second pressure plate, so water only trickles onto it. The second pressure plate is linked to a whooping 20 hatch covers and two retracting bridges.
On the layer 1 z-level
above the hallway is a second set of pumps facing the opposite direction but directly above the set which pump water into the hallway.
The second pressure plate opens the hatch covers blocking the input tile of these pumps. As soon as they open, they start sucking water out of the fortifications adjacent to the killing hallway on the layer below. The bridge north of these pumps is also triggered by the second pressure plate, but the bridge has a 100 tick delay before it opens. When this bridge opens, it dumps the water back down to the layer below, ready to be used again for the next wave.
On the z-level
below the killing hallway is (surprise surprise) another retracting bridge, a set of pumps and their input-tile-blocking hatch covers.
These pumps take magma from beneath the southern hatch covers and push to out onto the green glass bridge on the north side. The green glass bridge is located directly beneath the freeze zone of the layer above and once the magma is on the bridge, it melts the ice on the layer above. These hatches and the green glass bridge are also triggered by the second pressure plate. Again, the hatch covers open instantly, putting magma on the bridge in just a couple ticks, but the bridge won't retract until 100 ticks after the second pressure plate was initially triggered.
The layer beneath that is just a set of magma return pumps, fed from the north and going to the south.
When the green glass bridge above them retracts, it conveniently dumps the magma directly into the input space of these pumps, ready to be used for the next wave.
The real key to this whole contraption is the fact that pressure plates send an ON signal when they are first triggered
and an OFF signal after they've been untriggered for 100 ticks. It is hugely important that all these bridges and hatch covers
close.
Unfortunately, after all this work, I ran into a bit of a snag. While you can recover the bodies and possessions of creatures that get frozen in ice, you can only do so
by mining it out. The goblins (and all their precious goblinite) disappear from the world when the ice is melted instead of mined.
...
...
Oh well. It was a good idea at least.
For anybody who is interested, here is current map, world gen info and the embark location:
http://mkv25.net/dfma/map-9326-twinklespitCreated in DF v0.28.181.40d.
[WORLD_GEN]
[TITLE:TUNDRA TWO]
[SEED:3242670340]
[HISTORY_SEED:3497494431]
[NAME_SEED:2308961298]
[DIM:257:257]
[END_YEAR:1050]
[BEAST_END_YEAR:300:80]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:1]
[ELEVATION:1:400:800:800]
[RAINFALL:0:100:400:400]
[TEMPERATURE:25:75:400:400]
[DRAINAGE:0:100:400:400]
[VOLCANISM:0:100:400:400]
[SAVAGERY:0:100:400:400]
[ELEVATION_FREQUENCY:1:1:1:1:1:1]
[RAIN_FREQUENCY:1:1:1:1:1:1]
[DRAINAGE_FREQUENCY:1:1:1:1:1:1]
[TEMPERATURE_FREQUENCY:1:1:1:1:1:1]
[SAVAGERY_FREQUENCY:1:1:1:1:1:1]
[VOLCANISM_FREQUENCY:1:1:1:1:1:1]
[GOOD_SQ_COUNTS:100:1000:2000]
[EVIL_SQ_COUNTS:100:1000:2000]
[PEAK_NUMBER_MIN:50]
[OCEAN_EDGE_MIN:2]
[VOLCANO_MIN:15]
[REGION_COUNTS:SWAMP:1032:7:6]
[REGION_COUNTS:DESERT:1032:7:6]
[REGION_COUNTS:FOREST:4128:13:12]
[REGION_COUNTS:MOUNTAINS:8256:9:9]
[REGION_COUNTS:OCEAN:8256:7:6]
[REGION_COUNTS:GLACIER:0:0:0]
[REGION_COUNTS:TUNDRA:0:0:0]
[REGION_COUNTS:GRASSLAND:8256:13:12]
[REGION_COUNTS:HILLS:8256:13:12]
[EROSION_CYCLE_COUNT:250]
[RIVER_MINS:400:400]
[PERIODICALLY_ERODE_EXTREMES:1]
[OROGRAPHIC_PRECIPITATION:1]
[SUBREGION_MAX:2750]
[CAVE_MIN_SIZE:5]
[CAVE_MAX_SIZE:25]
[MOUNTAIN_CAVE_MIN:100]
[NON_MOUNTAIN_CAVE_MIN:200]
[ALL_CAVES_VISIBLE:1]
[SHOW_EMBARK_RIVER:2]
[SHOW_EMBARK_POOL:2]
[SHOW_EMBARK_M_POOL:2]
[SHOW_EMBARK_M_PIPE:2]
[SHOW_EMBARK_CHASM:2]
[SHOW_EMBARK_PIT:2]
[SHOW_EMBARK_OTHER:2]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:50]
[TOTAL_CIV_POPULATION:20000]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:8256:16512:8256]
[RAIN_RANGES:8256:16512:8256]
[DRAINAGE_RANGES:8256:16512:8256]
[SAVAGERY_RANGES:8256:16512:8256]
[VOLCANISM_RANGES:8256:16512:8256]
Inspired by the Degrinchinator
http://mkv25.net/dfma/movie-231-degrinchinator