I had an idea for a high speed switch which would activate a magma defence system using a direct command from the player without involving dwarves, as I'm sure most of us have suffered at the hands of lazy dwarves who are late to reach a lever at the crucial moment. While playing around with this idea, I found a simple combination which allows floors that only permit one way travel to specified creatures too be built. I couldn't see anything about it on the wiki, so I've made this thread.
The one way floor is just a hatch over a channelled out tile linked to a pressure plate:
# # # = wall
#H# H = Hatch over channelled tile
#^# ^ = Pressure plate
# #
A creature moving top to bottom will pass, but a creature moving from bottom to top will trigger the plate, lifting the hatch which breaks the path. This is different to the one way ramps exploit in that the creatures don't know its one way until they get there, and will try to path through it. This allows you to capture and manipulate creatures in some interesting ways.
High speed super switches
These use a trained animal sealed off with a system of doors and one way hatches
#D# D = Door
#H#
#^## <--- Attached to the adjacent hatches
#HD#
#^## <--- This plate is linked to whatever you want to trigger
#HD#
#^## <--- Attached to the adjacent hatches
#H#
#D#
This is basically two sets of traps each consisting of two one way hatches. Remember that the hatchess must be set to citizens trigger. Drop an unassigned hunting dog (war dogs also work but they are slower) onto either the top or bottom plate, then assign it to any random dwarf. The doors on the top and bottom are passable and provide paths for the dog to return to its master. The doors on the side are forbidden and they are how we operate the switch. As soon as the dog hits the plate it will be trapped on that tile. To trigger the switch unforbid the side door diagonal to the dog. It will immediately path to its owner, trigger the pressure plate in the middle, and then walk into the other trap. Make sure to reforbid the door you just used before using the switch again.
This could also be used as a crude repeater by unforbidding both side doors, however I think the dogs give up trying to return after a while. More testing is needed.
A modified version which will have a slightly longer response time, but will be able to hold the trigger down and operate in the same manner as a lever.
#D#
#H#
#^## <--- Attached to the adjacent hatches
#HD#
#HD#
#^## <--- This plate is linked to whatever you want to trigger + adjacent hatches
#H#
#D#
Automated goblin grinder
This design is basically a modified version of the switches, used for fort defence.
#H#
#^#
#T# T=Trap
#T#
#^#
#H#
Just make two one way hatches and fill the space between with weapon traps or spikes. Goblins go in, but can't leave, and try to path up and down, running over traps the whole time, and end up grinding themselves into teenie tiny bits. Alternatively just make fortifications on the walls and have some target practice for your marksdwarves, or have the floor drop away underneath them. Be creative.
The main problem with this design is that as soon as one goblin goes in, no more will be able to enter untill the first goblin moves off the plate. I suggest making an array of two or more of these next to each other, so when a goblin hits the first plate, the other goblins have another trapped path to take.
I have a couple of these systems up in my fortress, but they are brand spanking new and havent had any goblins through yet. I'll update with results when I get them.
For a simpler defence, you could just have a single one way floor at your entrance to filter out undesirables. Unlike a door, you can ensure dwarves can always pass but goblins never can.
Whenever using these to keep out nasties, make sure the channelled tile under the hatches do not open into your fortress or you could have some problems.
Other uses?
I think could use modified switches to build logic gates, so I might try my hand at some simple dwarfputing. So far I know I could make OR, NOR, NOT, and possibly AND and NAND gates (haven't thought too much about how to make the others yet).
Please feel free to post any ideas of your own, or improvements to any of these designs. Dwarfputing advice would be appreciated as well