Intersection cross-cut: watch ∩ algo-hrv

Axes: form_factor × algorithms

4 corpus entries disclose both tags.

Earliest disclosure: 2014-10-07

These entries are the direct inputs to OBVIOUSNESS_TEMPLATE.md. Any patent claim combining these two elements is anticipated or rendered obvious by the chain below.

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Inan et al. (2015) — ballistocardiography and seismocardiography review (2014-10-07)

• id: inan-2015-bcg-scg-review
• corpus: academic
• form factor: other
• creator: Omer T. Inan et al.
• disclosure: Inan OT, Migeotte P-F, Park K-S, Etemadi M, Tavakolian K, Casanella R, Zanetti J, Tank J, Funtova I, Prisk GK, Di Rienzo M. ‘Ballistocardiography and seismocardiography: a review of recent advances.’ IEEE Journal of Biomedical and Health Informatics 2015;19(4):1414-1427.
• ip status: public-domain
• sensors: sensor-accelerometer, sensor-piezoelectric
• algorithms: algo-hr, algo-hrv, algo-pwv-bp-estimation
• prior art notes: Reviews ballistocardiography (whole-body reaction force from cardiac ejection, measured at the seat/scale/bed) and seismocardiography (local chest vibration from cardiac motion, measured by accelerometers on the sternum) and their integration into bathroom scales, weighing chairs, beds, and chest patches — i.e. the mechanical-cardiac-signal route to heart rate, HRV, and cardiac-timing-interval / stroke-volume estimation. Prior art for claims reciting ‘measuring cardiac activity from a body-worn or support-mounted accelerometer/force sensor’, as both the BCG and SCG approaches and their wearable instantiations were collected and reviewed by 2015. Anchor for the BCG/SCG cross-cut.

Masimo W1 (2022) — first FDA-cleared continuous wrist medical-grade pulse oximetry watch (2022-05)

• id: masimo-w1-2022
• corpus: private
• form factor: watch
• creator: Masimo Corp.
• disclosure: Masimo Corp. ‘Masimo W1’ health-tracking watch, announced May 2022 — a wrist-worn device performing continuous medical-grade pulse oximetry (SpO2), pulse rate, perfusion index (PI), pleth variability index (PVi), respiratory rate from the PPG, and HRV, using Masimo’s SET/rainbow signal-extraction algorithms. (FDA cleared as a continuous-monitoring medical device.)
• ip status: patented
• sensors: sensor-ppg, sensor-spo2, sensor-multi-wavelength-ppg, sensor-accelerometer
• algorithms: algo-spo2-estimation, algo-hr, algo-hrv, algo-respiratory-rate
• prior art notes: Discloses a wrist-worn device performing continuous medical-grade pulse oximetry — SpO2, PR, perfusion index, PVi, RR-from-PPG, HRV — using established signal-extraction methods, distinguished from consumer spot-check SpO2 by continuous operation and clearance for medical use. Anticipates wrist-continuous-medical-SpO2 claims from 2022; the underlying two-wavelength SpO2 method is much older ([[aoyagi-1974-two-wavelength-pulse-oximetry]], [[mendelson-ochs-1988-reflectance-pulse-oximetry]], [[iso-80601-2-61-pulse-oximeter-equipment-2011]]). Product-side anchor for the watch × continuous-SpO2 cross-cut.

HealthyPi Move (ProtoCentral, 2026) — open-source medical-grade smartwatch (2024)

• id: healthypi-move-2026
• corpus: open
• form factor: watch
• creator: ProtoCentral Electronics
• disclosure: ProtoCentral Electronics (Bengaluru, India). ‘HealthyPi Move’ fully open-source AMOLED smartwatch — Crowd Supply campaign launched 2024, units shipping 15 May 2026. Sensors: single-lead ECG, dual-site PPG (wrist + finger), SpO2, blood-pressure trending, EDA/GSR, heart rate, HRV, respiration rate (derived), body temperature, 6-axis IMU. Compute: Nordic nRF5340 (dual ARM Cortex-M33). Display: AMOLED, 300 mAh battery. Companion app: Flutter, runs on Android/iOS/macOS/Windows/Linux, all data stored locally. Hardware design, firmware (Zephyr RTOS on nRF Connect SDK), and companion app all open-source. https://www.crowdsupply.com/protocentral/healthypi-move
• ip status: open-permissive
• sensors: sensor-ecg, sensor-ppg, sensor-spo2, sensor-multi-wavelength-ppg, sensor-gsr, sensor-accelerometer, sensor-gyroscope, sensor-skin-temperature
• algorithms: algo-hr, algo-hrv, algo-spo2-estimation, algo-respiratory-rate, algo-pwv-bp-estimation, algo-sleep-staging, algo-activity-classification, algo-step-count
• prior art notes: Discloses, as fully open-source hardware and firmware (CC and MIT-style licensing across components), a wrist-worn smartwatch with the full consumer-medical sensor stack: single-lead ECG between back-of-watch electrode and a finger-touch electrode; multi-wavelength reflectance PPG with SpO2 and BP-trending; EDA/GSR; skin temperature; 6-axis IMU; on-device Zephyr-RTOS application; AMOLED display; all-local data storage via cross-platform Flutter app. Anticipates wrist-multi-sensor-watch claims from 2024-2026 to the extent they recite combinations of these elements; as open prior art it is unencumbered and any patent claim reciting these combinations must distinguish over HealthyPi Move’s specific implementation. The product-side anchor for the ‘open watch with the full sensor stack’ cross-cut.

CogWatch (HardwareX, 2024) — open-source smartwatch for cognitive-load monitoring (2024)

• id: cogwatch-2024-hardwarex
• corpus: academic
• form factor: watch
• creator: (See HardwareX publication for full author list.)
• disclosure: ‘CogWatch: An open-source smartwatch platform for cognitive-load monitoring.’ HardwareX 19 (2024). Open-source smartwatch design — full hardware, firmware, and assembly documentation published in the open-hardware-focused journal HardwareX (Elsevier). https://www.hardware-x.com/article/S2468-0672(24)00032-4/fulltext
• ip status: public-domain
• sensors: sensor-ppg, sensor-gsr, sensor-accelerometer
• algorithms: algo-hr, algo-hrv, algo-stress-index, algo-cognitive-workload
• prior art notes: Discloses, as open-hardware (HardwareX is the canonical venue for full publication of open-hardware designs), a wrist-worn smartwatch instrumented for cognitive-load monitoring from PPG-derived HRV and EDA/GSR. Prior art for smartwatch-cognitive-load claims combining ‘a wrist-worn device’, ‘PPG and EDA sensors’, and ‘a derived cognitive-load metric’ from 2024.