Yeah, been trying to make use of traps and the like. Having pretty much zero luck.
Self powered traps. Miss a bit too often. Then need to be reset. Currently, this means your engis will often run face first into the goblins who are clearly still alive.. Kindof annoying atm, and really makes the traps not very viable.
Hatches, pressure plates, etc.
My next thought was to build my own.
Tried to use a pressure plate to make a room that shut on the goblins. aka, they step on the plate, the door in front and door behind close on them. but they don't work like that. Pressure plates only work while something is on them. So, the door would shut when it steps on it. and open right back up when it steps off..
Trying to use pressure plate to make a hatch, pitfall death trap has the same problem. Hatches open when they step on the plate. But that means they are on the plate, not the hatches, so they don't fall. and the hatch closes the moment they step off the plate.
I then tried to use a yak locked into a closed room with the pressure plate to create a trigger where the hatches open and close randomly. This technically works.. however, requires alot of hatches, and getting the yak into the trigger room is really hard, without being able to pasture underground.
I probably could make a gate, where its 1 square. doors go up IMMEDIATELY on both sides of the plate, locking the goblin in 1 square. With a level to open, a side wall up to let not goblins out.