Electronic wristband with a location transmitter for cruise passengers | post-ideas.com

Here is a design of an electronic wristband with a location transmitter for cruise passengers to ensure their safety in the event of disruptions, accidents, disasters, and missing persons on the high seas.

It's a complete, buildable concept for a cruise-safety wristband with reliable location + distress signaling at sea, tuned for real-world ship operations, rough weather, and privacy.

OceanSafe Wristband — System Design

1) Goals & Use Cases

* Everyday: cabin/door access, contactless payments (optional), shipwide “find my family,” muster drill check-ins, child/elder geofencing.
* Shipboard incidents (fire, power loss, missing person): live indoor location, broadcast instructions, authenticated check-ins at muster stations.
* Man-Overboard (MOB): automatic water-activated distress with GNSS position, visible strobe, homing for the bridge and nearby vessels.
* Abandon-ship / mass casualty: long-range position updates to bridge and lifeboats + SOS visible to rescue assets.

2) Hardware Architecture (dual-module)

A. Everyday Module (always worn on wrist)

* MCU: ultra-low-power ARM Cortex-M33 (with TrustZone + crypto)
* Radios

* UWB (6.5–8 GHz): room-level indoor positioning (±10–30 cm) for search/muster.
* BLE 5.3: low-power proximity, pairing with phone/kiosk, OTA updates.
* LoRa (868/915 MHz): whole-ship backhaul to gateways even through steel bulkheads; also supports text-only alerts in power outages.
* NFC: tap-to-muster, cabin access, payments.
* Sensors: 9-axis IMU (fall detection), barometer (pressurized decks vs open air), skin-contact sensor (anti-swap).
* Haptics + UI: vibration motor, multi-color status LED, 1.1" sunlight-readable e-paper for simple text/icons (evac route arrow, muster ID).
* Power: 200–300 mAh Li-polymer, wireless charging (Qi) or pogo-pin cradle.
* Ruggedization: IP68, -10 to +50 °C, salt-fog resistant; hypoallergenic silicone strap with breakaway + tamper clip.

B. Emergency Beacon Module (compact clip integrated into the strap)

> Lives docked in the wristband; auto-deploys or can be pulled free and clipped to a lifejacket shoulder for best antenna orientation.

* GNSS: multi-constellation (GPS/Galileo/BeiDou) with hot-start from the Everyday Module via secure handshake.
* AIS MOB / DSC VHF: 161.975/162.025 MHz AIS MOB transmissions + DSC distress burst (Ch. 70) — recognized by ship ECDIS/plotters.
* 121.5 MHz: optional close-range homing tone for RHIB/helo teams.
* Strobe: >1 candela, 360°, >20 hrs.
* Antenna: deployable tape antenna (coiled, spring-loaded) for VHF/121.5; automatically unreels on water contact or pull-tab.
* Power: sealed lithium primary (≈600–1000 mAh) with 5-year shelf life dedicated to distress only.
* Water Activation: dual-sensor (salinity + wet electrode) to avoid false positives from rain.

Why two modules?
* Keeps the MOB battery pristine for years.
* Lets the everyday functions be rechargeable/lightweight.
* Solves physics: a proper VHF/121.5 antenna needs length and vertical orientation not possible in a tiny wrist puck.

3) Ship Infrastructure

* UWB anchors every \~20–25 m in public areas, reduced density in cabins; PoE power; time-synced.
* LoRa gateways (2–4 per large ship) with UPS power; one gateway integrated into the bridge for redundancy.
* Bridge integration: ECDIS/AIS overlay, dedicated MOB console (with audio/visual alarm, last-known-position heatmap, muster dashboard).
* Muster beacons at stations: NFC taps + UWB zone detection for hands-free check-in.
* Offline mode: if all ship networks fail, Emergency Beacon still raises AIS/DSC externally.

4) Radio/Protocol Layers

* Indoor Ranging: UWB TWR/TDoA; update 1–2 Hz during incidents; 0.1 Hz in idle.
* Uplink: LoRa (SF7–10 adaptive) to ship server; encrypted payloads (AES-GCM with device-unique keys).
* Distress:

* MOB auto: water trigger → GNSS fix → AIS/DSC bursts every 1 min; strobe on.
* Manual SOS: long-press 5 s on the wristband → bridge alert over LoRa; if acknowledged, no VHF trip. If no ack within 30 s, escalate to AIS/DSC.
* Optional satellite backhaul (to shore ops): Iridium SBD module in select lifeboats/rafts; wristbands hand off IDs + last fix when aboard.

5) Power & Endurance (realistic targets)

* Everyday Module

* Normal: \~0.4–0.8 mA avg → 7–12 days per charge (display off, periodic UWB).
* Incident tracking: \~5–8 mA avg → 24–48 hrs.
* Emergency Beacon

* AIS/DSC 1 W bursts @ 60 s duty, GNSS running: ≥24 hrs continuous.
* Strobe: ≥20 hrs.
* Shelf: 5 years to 80% capacity at 25 °C.

6) UX & Workflows

Missing person onboard

1. Security flags guest in app → system shows last-seen + path trace using UWB + door taps.
2. Deck teams use “Proximity Mode” on handhelds (UWB/BLE) to home in within ±1 m.

Muster / evacuation

* Band vibrates + shows deck-specific route arrow and station ID; tap at station (NFC) or auto-check-in via UWB zone.
* Bridge sees live completion %, color-coded by zone; unaccounted guests prioritized to nearest teams.

Man Overboard

* Water hit or SOS long-press → MOB siren at bridge, MOB marker dropped on ECDIS, bearing vector to casualty, strobe active.
* Adjacent vessels see AIS MOB on their charts; ship executes Williamson turn; RHIBs home via 121.5 + visual.

7) Safety, Privacy, & Security

* Opt-in tiers: “Anonymous crowd flow” vs “Family share” vs “Full safety tracking.” Children/vulnerable adults default to “Full.”
* On-device store-and-forward: no raw location is accessible without ship’s HSM-backed keys.
* End-to-end encryption: ECC mutual auth, per-voyage rotating keys; no passenger PII on the Emergency Beacon.
* Physical: breakaway strap; no sharp edges; biocompatible materials; low SAR.
* Data retention: default purge 72 hrs post-voyage (configurable to legal requirements).

8) Regulatory & Standards (design to)

* Radio: FCC/CE/UKCA for BLE/UWB/LoRa; ITU-R M.1371 compliance for AIS, EN 303 098 (AIS), DSC (ETSI EN 300 338); 121.5 MHz homing (ICAO/RTCM guidance).
* Maritime: IEC 60945 (marine nav & radio equipment); IEC 62368-1 (electrical safety); IP68; MIL-STD-810H (shock, salt fog).
* Batteries: UN38.3 transport; IEC 62133-2; UL 2054.
* Accessibility: ISO 24507 (safety colors/symbols); haptic + visual redundancy.

9) Mechanical & Industrial

* Form factor: 45 × 45 × 12 mm everyday puck; 52 × 18 × 12 mm emergency clip (curved). Total on-wrist mass ≈ 55–65 g.
* Materials: glass-filled polycarbonate housing; 316L stainless fasteners; silicone or FKM strap; conformal-coated PCB.
* Serviceability: everyday battery user-rechargeable; emergency cell factory-sealed with replace at 5-year service.

10) Firmware States (high level)

* Idle → Power-save (BLE ads, rare UWB pings)
* Active → Indoor tracking (incident/muster)
* Alert (bridge-acknowledged) → high-rate tracking, no VHF
* MOB Armed (wet) → GNSS warm → AIS/DSC burst loop + strobe
* Post-rescue → Secure handover; beacon silenced by authenticated NFC from bridge device

11) Ship Software

* Bridge UI: ECDIS overlay, MOB pane (bearing, CPA/TTG), heatmaps, muster completion, filtered passenger search, replay.
* Ops Dashboard: battery fleet health, anchor coverage map, dead-zone detector, firmware OTA waves.
* APIs: REST/WebSocket; privacy-scoped endpoints; audit logging.

12) Manufacturing & Cost (ballpark BOM at volume)

* Everyday Module: \$23–35 (MCU+UWB \~\$8–12, BLE in combo, LoRa \~\$3–5, sensors \~\$2–3, e-paper \~\$4–6, haptics/casing).
* Emergency Beacon: \$38–55 (GNSS \~\$3–5, AIS/DSC RF \~\$12–18, strobe+drivers \~\$2, primary cell \~\$4–6, mechanicals/antenna).
* Total BOM: \$61–90; landed COGS with test/assembly: \~\$85–120. Rental model to passengers is typical.

13) Risk & Mitigations

* VHF antenna efficiency on a wrist → detachable clip + auto-deploy tape antenna to get vertical separation above water.
* False water triggers → dual sensing + long-press cancel within 15 s (no AIS sent if canceled) + bridge confirmation window.
* Steel bulkhead shadowing → LoRa diversity gateways + store-and-forward + UWB anchor overlap.
* Battery neglect → nightly cabin chargers + app/TV reminders + crew dash for outliers.
* Privacy backlash → explicit, tiered consent + on-device processing + short retention.

14) Validation & Tests

* RF chamber: AIS sensitivity and adjacent-channel power; UWB positioning accuracy across decks.
* Overboard drills: live drops at different sea states; verify pick-up ranges (target: AIS seen at ≥4–5 NM by bridge antenna).
* Saltwater durability: 96-hr salt-fog, dunk cycles, detergent/hand-sanitizer exposure.
* Lifejacket integration: one-hand clip-on within 3 s; gloves test.
* Human factors: vibration patterns vs ambient noise; color-blind-safe iconography on e-paper.

15) What to build first (MVP → V2)

* MVP: Everyday Module + LoRa/UWB + bridge/muster software; Emergency Beacon clip with manual SOS only (no auto-wet).
* V1.5: add water activation + deployable antenna + DSC.
* V2: add 121.5 homing, satellite handoff from lifeboats, contactless payments.