The following is the text from the Empty Room, Tricks, and Traps document. The additional information is added to increase agency.
Tripwire: These refer to strings or wires stretched taut that will trigger the trap of their tension is altered. Although difficult to see against a varied background, these can often be detected by careful observation and bright light. In addition to being strung across corridors, they may be attached to the inside of lids of containers, behind doors, along stairs, or to objects on pedestals.The most important thing about detecting these is lighting. It is quite easy in good light to miss a low strung tripwire. The material the wire is made from is an important fact, as well as how it is prepared. If the characters are carrying a light source and state that they are inspecting the floor, they should discover any exposed tripwire.
If the wire is made from metal and not covered in some sort of non-reflective material, it may reflect the light from a sun-rod or torch. If the line is made from rope, cord, or twine, wetness, mold, rot, and decay may cause the trap itself to be triggered if left alone long enough.
A tripwire, over time may sag, stretch out, and eventually be laying on the actual floor itself. These will still trigger the trap, however there should be a reduced chance (~25%) of actually triggering it for each character that crosses the trap.
This category often covers snares also. These and other types of tripwires are often camouflaged and hidden from view. In this case, the object hiding the tripwire can be described.
- Leaves choke the hallway ahead
- Rubble is lying all about the hallway
- Mist swirls about the floor
- A curtain hangs in the hallway
Lids: These “mechanical” triggers are very simple - any object that covers a pit that doesn’t look like the top of a pit is a lid. This may also refer to false doors that open into walls that spring traps. Prodding and tapping are very effective at detecting these kinds of traps.
Breakaway pits are usually camouflaged, but any sort of testing or prodding will indicate either that the floor is not solid, or that the covering has some give to it. You must also consider the terrain and the substance used to cover the breakaway pit. Leaves and sticks outside, and a carpet indoors.
Latch pits have moving parts. There is some support for the latch, and usually some way for the latch to reset. This means a wheel or gear hidden nearby. Also, it is more difficult to hide the seam of a latched pit.
Teeter-totter pits are easy enough to detect by prodding, but as a side effect from heavy use, may not center correctly. One side may be raised up an inch or more, while the other is low. Or if it is poorly made, the wrong side of the pit could be present.