<b>OPAL</b>: A multimodal ambient sensor dataset for activity, occupancy, and energy analysis in an office workspace

Two connected rooms were instrumented: Room 207, the main workspace, and Room 205, a meeting and common area.</p><p dir="ltr">The release combines appliance-level electrical measurements from 21 smart plugs, motion and door-contact events, ambient temperature, camera-generated event states, participant-level activity annotations for three primary participants across 11 workplace activity classes, and room-level occupancy counts that also include non-target laboratory members.</p><p dir="ltr">The release covers 2026-05-14 14:00 to 2026-06-16 15:00 (KST) and comprises 1,360 daily CSV files holding 33,803,409 records, 1.96 GB in total, across 34 date directories.

It ships with a data dictionary, a labelling guideline, quality-control documentation, machine-readable metadata in schema.org, DCAT-AP 2.1 and MLCommons Croissant form, and SHA-256 checksums for every file.</p><p dir="ltr">Raw video, raw audio, speech content, conversation transcripts, identifiable facial images and participant identity mapping files are not part of the release. Cameras were used for annotation verification only; the only sound-related signal published is the binary sound-event state reported by the Room 205 camera firmware.</p><p dir="ltr">The dataset supports human activity recognition, occupancy estimation, multimodal sensor fusion, appliance-level energy analysis and privacy-preserving ambient sensing in shared workplaces.</p>