Domain: Engineering — Electrical Engineering
Target concept: The CO₂ air quality sensor changes the LED color in response to nearby breathing, with the change appearing after the sensor's normal few-second diffusion-limited delay rather than instantly.

Video generation prompt: On the desk, an energized CO₂ sensor with an LED indicator sits in view; a person approaches, blows into the sensor, steps back, and repeats the process a second time.

Evaluation guide:
(i) Target concept: Optical feedback of CO₂ concentration change via LED state transition, with the sensor's response following its normal diffusion-limited timescale rather than being instantaneous.
Minimum mechanism: Sensor must be powered and calibrated; human exhalation delivers locally elevated CO₂ (breath CO₂ is roughly 40,000 ppm) toward the sensor's inlet; the LED driver responds only once enough CO₂ has diffused into the sensing chamber, which typically takes a few seconds after exhalation begins (not a sub-second reaction); no artificial external delay or software buffering is added beyond the sensor's own normal response time.
(ii)Storyline: [Frame 0–2] Stable wide shot: sensor centered on desk, LED glowing baseline color, person out-of-frame left. [Frame 3–5] Person enters frame, approaches sensor directly along central axis, stops at consistent distance. [Frame 6–8] Person exhales toward the sensor inlet; within a few seconds the LED transitions to its response color. [Frame 9–11] Person steps back fully; the LED reverts toward its baseline color over a similar few-second span as the CO₂ disperses. [Frame 12–14] Person repeats the approach. [Frame 15–17] Second exhale: the LED again transitions to the response color on a comparable delay. [Frame 18–20] Person steps back; LED reverts. All phases viewed from fixed frontal desk-level angle; sensor never leaves frame; LED always fully visible and unoccluded; no cuts or perspective shifts.

Manual:
Experimental Procedure
1. Place energized CO₂ sensor with visible LED indicator on desk.
2. Person stands in front, blows steadily toward sensor inlet for ~1 second.
3. Person steps back fully, pauses.
4. Person repeats blowing toward sensor.
Observation of Experimental Phenomena
LED changes from its baseline color (e.g., green) to a response color (e.g., red or yellow) within a few seconds after each blowing event, as CO₂ diffuses into the sensing chamber, and returns to baseline over a similar timescale once the person steps back and the CO₂ disperses.
Summary of Experimental Principles
The CO₂ air quality sensor changes its LED color in response to elevated CO₂ in exhaled breath, detected via non-dispersive infrared (NDIR) absorption sensing; the response follows the sensor's normal diffusion-limited timescale rather than occurring instantaneously.

Prompt Grounding rubric:
level_1: No CO₂ sensor is visible on the desk; no LED indicator is present on the sensor; no person appears in frame; no blowing action or approach/retreat motion is depicted at all.
level_2: CO₂ sensor appears on desk but has no visible LED indicator; or a person appears but never approaches or blows toward the sensor; or only a single static pose is shown with no approach-retreat movement; core setup elements (sensor, LED, person, blowing motion) are largely missing.
level_3: CO₂ sensor with a visible LED sits on the desk; a person enters frame, approaches the sensor, and performs one blowing action toward it; the sensor stays in place; only one approach-and-retreat cycle is completed (no second repetition); framing and object presence otherwise match the described setup.
level_4: CO₂ sensor with LED indicator is on the desk; person approaches, blows toward the sensor, steps back, and repeats the approach-blow-retreat cycle at least once; sensor and LED are present throughout; however, the sensor or LED is partially blocked from view during at least one phase, or the camera framing/distance shifts noticeably between the two repetitions.
level_5: CO₂ sensor with clearly visible LED remains stably positioned on the desk throughout; person is fully visible performing two complete approach → blow → step-back cycles with consistent framing and distance; the sensor and LED stay unobstructed in every phase; no extra people, objects, or actions appear beyond those in the posted prompt.

Scientific and Causal Correctness rubric:
level_1: LED never changes color throughout the entire sequence; or it changes color with no relation to either blowing event; or a color change happens while the person is off-screen or before any exhalation begins.
level_2: LED changes color once, but the change is not timed to follow either blowing action (e.g., it changes while the person is still approaching, before exhaling); or the LED switches to an undefined third hue outside the baseline/response pair (e.g., green shifting directly to blue rather than to the response color); or several colors appear on the LED at once.
level_3: LED changes from its baseline color to a single, consistent response color following the first blowing action, with the change appearing only after the person exhales (allowing for the sensor's normal few-second response delay); this pairing is clear for the first cycle, but the second blowing action produces no matching color change or an inconsistent one.
level_4: LED transitions from baseline to the same response color after each of the two blowing actions, with each transition appearing only after exhalation begins (not before); LED returns to baseline color before the next blow begins; no flickering or blended colors appear at any point; the causal link between exhaling and the color response is visually clear for both cycles.
level_5: LED holds a single stable baseline color while idle and shifts cleanly (no fade or gradient) to a single stable response color following each of the two blowing actions, with the same hue used both times; each reversion to baseline occurs only after the person has stepped back, not before; no color transition ever precedes its corresponding blow or the person's return; the LED's on-screen behavior is fully consistent between both cycles.

Spatiotemporal Consistency rubric:
level_1: The sensor's position on the desk jumps abruptly between frames with no visible motion carrying it there; the person appears or disappears between the desk and off-screen without a continuous walking motion; the LED flickers erratically or disappears from view for no visible reason; the room's lighting shifts abruptly, such as a shadow suddenly appearing or disappearing with no cause; the desk or sensor housing visibly warps or rotates on its own.
level_2: The sensor visibly shifts position or angle on the desk between the two cycles without any hand or object moving it; the person's walk toward or away from the sensor contains an unnatural pause, skip, or gap in motion; the LED's brightness flickers or wavers independent of any color change; the shadow cast by the sensor or person changes noticeably between the two cycles without a corresponding change in the light source.
level_3: The sensor stays in the same spot on the desk across both cycles; the person's approach and retreat are smooth, continuous walking motions rather than abrupt jumps; the LED stays visible throughout except for brief, natural occlusion by the person's body that clears within a moment; the desk and background do not warp, duplicate, or disappear at any point.
level_4: The sensor remains fixed in the same location and orientation on the desk for the entire sequence; the person's forward approach and backward retreat each follow a consistent path toward and away from the sensor; the LED and sensor body stay fully visible and unobstructed during both blowing actions; the desk surface, sensor housing, and background lighting look the same in the first cycle as in the second.
level_5: The sensor's position, orientation, and size on the desk stay identical across every frame of both cycles; the person's two approach-and-retreat walks are smooth, follow the same path and pace, and show natural continuous limb motion with no stutter; the LED and sensor housing show no visible flicker, warping, or duplication at any point; shadows cast by the person and by the sensor's housing keep the same direction and length across all frames, consistent with one fixed light source and a stationary camera.