Instrument · what the count rests on

What the headcount is made of.

The app on the previous page prints one number per minute. This page opens the back of the instrument and shows what that number rests on: every measured day on one clock, the four ways of computing a level and how often they agree, the minutes with a known headcount the count map passes through, what an empty floor reads night by night, how often each rule would have cried wolf on a night nobody was there, which receivers raise alarms alone, whether the phones in the room move with the radio reading, and whether a warm node reads differently from a cool one.

Also: each receiver and radio configuration, day against night.

Companion labs in Occupancy

In plain words Pick a day on the calendar and see people per minute: the Wi-Fi room level, calibrated that day against the Bluetooth devices the fleet heard, and fused with them. The people scale is a stated assumption you can move. A gap is a gap; nobody fills it with a zero.

The capture format Bluetooth in the room

Method for the level panels: Envelope, our transmitter only · Doppler 20–60 Hz, our transmitter only · Delivered-rate collapse · Envelope, every transmitter

The calibration

The anchors of the count map on `env_inj`: for each labelled count, the fleet minutes inside its labelled windows and where their level sat. Zero is the certified-empty floor by construction.
People	Minutes	Level median (oct)	p10	p90
0	—	0.000	—	—
2	8	2.124	1.429	2.556
3	18	2.170	1.508	2.658

One integer per minute with an interval, from a piecewise-linear map through the anchors. Zero is the verified empty-night floor. Counts are withheld when any receiver uses an assumed baseline. Bounds round outward; above the top anchor the upper bound is open. This is a descriptive receiver-bootstrap range, not a validated headcount prediction interval.

Every labelled window the snapshot read. A label is a person's statement with a basis; it is what the map passes through.
Label	Day	Window (library time)	People	Source	Basis
OL-001	2026-09-02	10:45–10:49	2	diary	Two people filming a promotional video, moving all over the floor, before 11:20 (diary 2026-09-02 §3, the researcher's own timeline). The window edges are the detector's episode edges on nine receivers (§4b); the count is the researcher's. The quiet minutes between this and OL-002 are unlabelled because where the crew stood then is not recorded.
OL-002	2026-09-02	10:57–11:01	2	diary	Same two people filming (diary 2026-09-02 §3, 'the 10:45 and 10:57 episodes fall in the window the researcher places two people making a video on the floor'). Window edges from §4b; count from the researcher.
OL-003	2026-09-02	11:16–11:26	3	diary	Three people: the diary's calibration (§10) labels 'eighteen minutes with three people' across the 11:16 to 11:25 and 11:31 to 11:38 episodes, inside the researcher's own 11:20 to 11:45 visit (§3). Window edges from §4b; count from the researcher.
OL-004	2026-09-02	11:31–11:39	3	diary	Three people, the second of the two episodes the diary's calibration (§10) labels as three people, inside the researcher's 11:20 to 11:45 visit (§3). Window edges from §4b; count from the researcher.

Edges calibrated on 2026-09-02 (nine receivers, the transmitter-scoped envelope): fleet level 0.00 octaves on 62 quiet minutes (p90 0.03), 1.05 on nine minutes with two moving people, 1.10 on eighteen minutes with three people. Those levels were measured on reduction schema 4, where the envelope divided neighbouring tones of one chain; the page now reads the corrected two-chain ratio, and the edges are refitted once 2026-09-02 is re-derived. Empty against occupied separated; two against three people did not. `high` has never been observed and is a placeholder. Buckets are levels, not head counts.

JSON: days · agreement · nights · false alarms · receivers · bystanders · temperature · episodes