Traps: Detection Methods

I thought it would be good to summarize my previous posts on trap triggers using a list sorted by detection methods, so that GMs could compare the party's behavior to the kinds of triggers they would find. (This doesn't include trap results yet, because I haven't categorized them.) The detection methods can be sorted by the standard senses, arranged according to how close you have to be:

• (Aud)ible,
• (Vis)ible,
• (Odor)ous, (Warm)th, (El)ectric (...),
• (Tact)ile,
• (Gust)atory (taste)

"Audible" and "Visible" can switch places, depending on environmental factors (obstacles to sound or light.) I place "Audible" first because it will always work, whereas "Visible" details are only visible when there's light available.

Odors generally require getting closer; figure you have to be in the same room at least, with distance diminishing for fainter odors. I also group things like sensing temperature or having your hair stand on end because of static electricity into the same category.

"Tactile" and "Gustatory" both involve direct contact, but since many poisons and potions require consumption, I ranked it as being "closer" than merely touching an object.

If you are surprised by a trap, you are caught in it; thus, you attempt to detect it beforehand, to eliminate a surprise roll. We can use the same detection methods as I described earlier, although I've renamed them slightly here so that I can abbreviate them in my sorted list:

1. (N)one, just blunder in: roll for surprise as normal;
2. (S)low Entry: no surprise roll if obviously Audible or Visible;
3. (P)aranoid Entry, stop and scan first: no roll if obviously Audible, Visible, or Odorous;
4. (C)autious Entry, test from safe distance where possible: no roll if obviously Visible, Odorous, or indirectly Tactile, or any Audible details;
5. (T)horough Tests: no roll needed for any senses, but may suffer effects.

Sensory details can be hidden by some obstacle or disguise from senses that act over a distance (Audible, Visible, Odorous, Warmth, Electric.) To make the detail obvious, a person searching must mention what they do about the obstacle. For example, a door is usually plainly visible, but a door behind a tapestry is hidden until the tapestry is moved. Hidden details also include audible, visible or other phenomena that only occur under specific tests, like a hollow sound made by tapping an object; this is why Cautious Entry detects any Audible sounds, not just obviously Audible sounds. In general, a hidden detail requires increasing the thoroughness of a search procedure by one level.

Some details can also be observed indirectly, which provides less information. For example, a backlit creature or statue around a corner will cast a shadow; observant characters will see the shadow, but not know what object is casting the shadow. This distinction is most important for tactile details; touching an object or surface with a pole or weapon only allows indirect Tactile details, such as pressure or "give".

Detection methods, sorted first by sense and second by thoroughness, and the kinds of triggers or details they discover:

1. Aud/N: really large gear or pulley systems, huge volumes of pouring water used in delays
2. Aud/S: typical gear/pulley systems or water/sand delays
3. Aud/P: short delays (tiny volume of water or sand pouring into or draining out of container)
4. Aud/C: secret ducts or compartments (tap area;) 
5. Vis/N: obvious mechanical systems of any kind, such as tripwire in lit room
6. Vis/S: obvious vent, catch, or lever; typical tripwires and pressure plates
7. Vis/P: tiny vent, hidden shutter, backlit springs, latches or other mechanics when viewed through a crack
8. Vis/C: tiny spring or lever triggers
9. Odor/S: delay that uses burning material
10. Tact/C: pressure plates (press plate, but may trigger;)  buried plates (poke through sand/mud;) hidden springs, wires, or levers (poke through crack)

I've grouped all compression and equilibrium plates together with pressure plates in the above list, since they are about equally hard to find; the differences between them mainly deal with how they are reset or how versatile they are. However, a plate that incorporates a bellows or lever might be detectable by sound as well as visually.