Intersection cross-cut: `watch` ∩ `sensor-ppg`

Axes: form_factor × sensors

21 corpus entries disclose both tags.

Earliest disclosure: 1988-10

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.

Mendelson & Ochs (1988) — reflectance-mode pulse oximetry / skin-reflectance PPG (1988-10)

id: mendelson-ochs-1988-reflectance-pulse-oximetry
corpus: academic
form factor: other
creator: Yitzhak Mendelson / Burt D. Ochs
disclosure: Mendelson Y, Ochs BD. ‘Noninvasive pulse oximetry utilizing skin reflectance photoplethysmography.’ IEEE Transactions on Biomedical Engineering 1988;35(10):798-805.
ip status: public-domain
sensors: sensor-ppg, sensor-spo2, sensor-multi-wavelength-ppg
algorithms: algo-spo2-estimation, algo-hr
prior art notes: Establishes pulse oximetry by reflectance (light source and detector on the same side of the tissue) rather than transmission — the geometry every wrist, forehead, ring, chest, and earbud PPG/SpO2 wearable uses, since those sites cannot be transilluminated. Any wearable-SpO2 claim reciting ‘a reflectance photoplethysmography sensor’ or ‘a light source and photodetector arranged on a common surface against the skin’ reads on Mendelson & Ochs 1988. Anchor for the reflectance-PPG/SpO2 cross-cut on non-fingertip sites.

Garmin Forerunner 201 (2003) — wristworn GPS running watch with pace/distance and heart-rate (strap) integration (2003)

id: garmin-forerunner-201-2003
corpus: private
form factor: watch
creator: Garmin Ltd.
disclosure: Garmin Ltd. ‘Forerunner 101/201’, introduced 2003 — a wrist-worn GPS receiver/watch logging pace, distance, route, and (with a paired chest strap) heart rate, with workout history and a web/PC sync. Later Garmin watches (Fenix/Forerunner with the ‘Elevate’ optical sensor, c. 2015) moved heart rate, and subsequently SpO2 (pulse ox) and respiration, onto the wrist.
ip status: patented
sensors: sensor-accelerometer, sensor-ecg, sensor-ppg
algorithms: algo-hr, algo-step-count, algo-calorie-estimation, algo-activity-classification
prior art notes: Discloses a wrist-worn GPS sport watch deriving pace, distance, and route, integrating heart rate from a paired electrode chest strap, and syncing workout history to a host — and, in later Garmin models, on-wrist optical-PPG heart rate, SpO2, and respiration. Anticipates GPS-sport-watch claims from 2003 and (for the later models) wrist-optical-vitals claims. Product-side anchor for the watch × GPS-fitness cross-cut.

Pantelopoulos & Bourbakis (2010) — survey on wearable sensor-based systems for health monitoring and prognosis (2010-01)

id: pantelopoulos-bourbakis-2010-wearable-health-survey
corpus: academic
form factor: other
creator: Alexandros Pantelopoulos / Nikolaos G. Bourbakis
disclosure: Pantelopoulos A, Bourbakis NG. ‘A survey on wearable sensor-based systems for health monitoring and prognosis.’ IEEE Transactions on Systems, Man, and Cybernetics, Part C (Applications and Reviews) 2010;40(1):1-12.
ip status: public-domain
sensors: sensor-ecg, sensor-ppg, sensor-spo2, sensor-accelerometer, sensor-skin-temperature, sensor-respiration-impedance
algorithms: algo-hr, algo-arrhythmia-classification, algo-spo2-estimation, algo-fall-detection, algo-activity-classification
prior art notes: Surveys, as of 2010, the architecture and components of wearable health-monitoring systems — sensors (ECG, PPG, SpO2, accelerometry, temperature, respiration), garment- and patch- and watch-based form factors, on-body processing, wireless body-area networking, and the analytics (arrhythmia, fall, activity, deterioration prediction). Prior art establishing that the general ‘multi-sensor wearable + body-area network + cloud analytics’ system architecture and its building blocks were collected and published by 2010 — useful against later claims to the bare system architecture. General anchor.

Patel et al. (2012) — ‘A review of wearable sensors and systems with application in rehabilitation’ (2012-04-20)

id: patel-bonato-2012-wearable-sensors-rehab-review
corpus: academic
form factor: other
creator: Shyamal Patel / Hyung Park / Paolo Bonato et al.
disclosure: Patel S, Park H, Bonato P, Chan L, Rodgers M. ‘A review of wearable sensors and systems with application in rehabilitation.’ Journal of NeuroEngineering and Rehabilitation 2012;9:21.
ip status: public-domain
sensors: sensor-accelerometer, sensor-gyroscope, sensor-emg, sensor-ecg, sensor-ppg, sensor-pressure-skin
algorithms: algo-gait-analysis, algo-activity-classification, algo-fall-detection, algo-tremor-detection, algo-bradykinesia-detection, algo-posture-detection
prior art notes: Reviews, as of 2012, wearable inertial/EMG/pressure sensor systems for movement and physiological monitoring in rehabilitation and chronic-disease management — gait analysis, activity and posture classification, fall detection, tremor and bradykinesia quantification (Parkinson’s), with the sensor placements (foot/insole, shank, thigh, trunk, wrist, forearm) and algorithms. Prior art for wearable movement-disorder and gait-monitoring claims reciting any of the placements/analytics surveyed; collected and published by 2012. General anchor for the gait / tremor / activity cross-cuts.

Microsoft Band (2014) — ten-sensor wristband (optical HR, GPS, GSR, UV, skin temp, barometer, ambient light, capacitive, microphone, IMU) (2014-10-30)

id: microsoft-band-2014
corpus: private
form factor: watch
creator: Microsoft Corp.
disclosure: Microsoft Corp. ‘Microsoft Band’, released 30 October 2014 — a wristband integrating ten sensors: an optical (PPG) heart-rate sensor, a 3-axis accelerometer/gyroscope, GPS, an ambient-light sensor, a skin-temperature sensor, a UV sensor, a capacitive (wear-detection) sensor, a galvanic-skin-response sensor, a microphone, and a barometer (added in Band 2).
ip status: patented
sensors: sensor-ppg, sensor-accelerometer, sensor-gyroscope, sensor-skin-temperature, sensor-uv, sensor-gsr, sensor-barometer, sensor-photodiode-ambient, sensor-microphone-air
algorithms: algo-hr, algo-step-count, algo-calorie-estimation, algo-sleep-staging, algo-stress-index, algo-uv-dose-tracking
prior art notes: Discloses a single wristband integrating an unusually broad sensor suite — reflectance-PPG HR, IMU, GPS, skin temperature, UV exposure, galvanic skin response (electrodermal activity), barometer, ambient light, capacitive wear-detection, and a microphone — feeding HR, activity, sleep, UV dose, and stress-index estimations. Prior art for multi-sensor-wristband claims reciting combinations of these sensors (notably wrist GSR/EDA + PPG + skin temperature for stress) from October 2014. Product-side anchor for the multi-sensor wristband cross-cut.

Fitbit Charge HR (2015) — wristband with continuous wrist-PPG heart rate (‘PurePulse’) (2015-01-06)

id: fitbit-charge-hr-2015
corpus: private
form factor: watch
creator: Fitbit, Inc.
disclosure: Fitbit, Inc. ‘Fitbit Charge HR’, announced January 2015 — a wristband with ‘PurePulse’ continuous optical (green-LED PPG) heart rate, a 3-axis accelerometer, steps/distance/floors/calories/active-minutes, automatic sleep tracking, and call/text notifications.
ip status: patented
sensors: sensor-ppg, sensor-accelerometer, sensor-barometer
algorithms: algo-hr, algo-step-count, algo-calorie-estimation, algo-activity-classification, algo-sleep-staging
prior art notes: Discloses a wristband with continuous green-LED reflectance-PPG heart rate plus accelerometry and an altimeter, deriving HR, steps, floors, calories, and sleep, with phone notifications. A mainstream realization of [[mendelson-ochs-1988-reflectance-pulse-oximetry]]-geometry wrist PPG; anticipates wrist-PPG-HR-band claims from January 2015. Product-side anchor for the watch × PPG cross-cut alongside [[apple-watch-original-2015]].

Apple Watch (1st generation, 2015) — wrist green-PPG heart rate and activity (2015-04-24)

id: apple-watch-original-2015
corpus: private
form factor: watch
creator: Apple Inc.
disclosure: Apple Inc. ‘Apple Watch’, announced September 2014, available 24 April 2015 — a wrist-worn device with a green/infrared photoplethysmography heart-rate sensor against the dorsal wrist, accelerometer and gyroscope, and activity/exercise tracking.
ip status: patented
sensors: sensor-ppg, sensor-multi-wavelength-ppg, sensor-accelerometer, sensor-gyroscope
algorithms: algo-hr, algo-step-count, algo-calorie-estimation, algo-activity-classification
prior art notes: Discloses a wristworn device with a dorsal-wrist green-LED photoplethysmography heart-rate sensor (with IR for low-perfusion conditions), inertial sensors, and continuous HR/activity tracking. Anticipates wristworn-PPG-HR claims to the extent they postdate April 2015; combined with the much earlier PPG principle ([[hertzman-1937-photoplethysmography]]) and wrist form factor, the combination is in any case obvious under [[obviousness-template]]. Product-side anchor for the watch × PPG cross-cut.

Mukkamala et al. (2015) — ‘Toward Ubiquitous Blood Pressure Monitoring via Pulse Transit Time: Theory and Practice’ (2015-08)

id: mukkamala-2015-ptt-cuffless-bp-review
corpus: academic
form factor: other
creator: Ramakrishna Mukkamala et al.
disclosure: Mukkamala R, Hahn J-O, Inan OT, Mestha LK, Kim C-S, Töreyin H, Kyal S. ‘Toward Ubiquitous Blood Pressure Monitoring via Pulse Transit Time: Theory and Practice.’ IEEE Transactions on Biomedical Engineering 2015;62(8):1879-1901.
ip status: public-domain
sensors: sensor-ecg, sensor-ppg, sensor-cuffless-bp-ptt, sensor-cuffless-bp-tonometry
algorithms: algo-pwv-bp-estimation
prior art notes: Canonical 2015 review of cuffless blood-pressure estimation by pulse transit time / pulse arrival time / pulse wave velocity: the physiological models, the practical sensor configurations (ECG+PPG, dual PPG, ballistocardiogram+PPG), the calibration strategies, and the accuracy limitations. Prior art for cuffless-BP wearable claims reciting any of the configurations or calibration approaches surveyed here — they were collected, modeled, and published by 2015. Combined with watch/ring/patch form-factor disclosures, makes wearable PTT-based BP an obvious combination under [[obviousness-template]].

Heikenfeld et al. (2018) — ‘Wearable sensors: modalities, challenges, and prospects’ (2018-01-16)

id: heikenfeld-2018-wearable-sensors-lab-on-chip-review
corpus: academic
form factor: other
creator: Jason Heikenfeld et al.
disclosure: Heikenfeld J, Jajack A, Rogers J, Gutruf P, Tian L, Pan T, Li R, Khine M, Kim J, Wang J, Kim J. ‘Wearable sensors: modalities, challenges, and prospects.’ Lab on a Chip 2018;18(2):217-248.
ip status: public-domain
sensors: sensor-ppg, sensor-ecg, sensor-eeg, sensor-glucose-cgm, sensor-lactate, sensor-cortisol, sensor-skin-temperature, sensor-bioimpedance
prior art notes: Authoritative 2018 review collecting wearable sensing across modalities — physical (motion, BCG/SCG, mechanoacoustic), electrophysiological (ECG/EMG/EEG), optical (PPG/SpO2, near-IR), thermal, electrochemical (sweat, saliva, tears, interstitial), and stimulation-coupled — across form factors (patch, watch, tattoo, contact lens, garment) and the challenges of body-fluid sampling, calibration, motion-artifact handling, and skin-electronics interfacing. Prior art establishing that the modality/form-factor combinations enumerated here were collected and surveyed by 2018; useful against later claims to those combinations. General anchor.

Pine64 PineTime (2018-2020) — low-cost open-source smartwatch (2018-09)

id: pine64-pinetime-2020
corpus: open
form factor: watch
creator: Pine Store Ltd. (Pine64)
disclosure: Pine64. ‘PineTime’ open-source smartwatch — first announced September 2018, dev-kit shipping early 2020, sealed units (~US$30) shipping from late 2020. Hardware: Nordic nRF52832 (ARM Cortex-M4), heart-rate monitor, 3-axis accelerometer, touchscreen, BLE. Open firmware: ‘InfiniTime’ (C++/FreeRTOS) at github.com/InfiniTimeOrg/InfiniTime; ‘Wasp-OS’ (Python/MicroPython) at github.com/daniel-thompson/wasp-os. Hardware schematics at wiki.pine64.org/wiki/PineTime. https://pine64.com/product/pinetime-smartwatch-sealed/
ip status: open-permissive
sensors: sensor-ppg, sensor-accelerometer
algorithms: algo-hr, algo-step-count
prior art notes: Discloses a low-cost (US$30) wrist-worn smartwatch with PPG-HR sensor, accelerometer, touchscreen, BLE, and fully open-source firmware (InfiniTime in C++/FreeRTOS, or Wasp-OS in Python/MicroPython on the same hardware) and published hardware schematics. Establishes (since 2018-2020) that the basic smartwatch architecture — MCU + PPG + accel + display + BLE + open firmware — is unencumbered open-hardware prior art. Distinct from [[healthypi-move-2026]] in being earlier and simpler; together they establish open-watch prior art across a >5-year span.

FDA De Novo DEN180042 (2018) — photoplethysmograph analysis software for over-the-counter irregular-rhythm (possible-AFib) notification (Apple Watch) (2018-09-11)

id: fda-den180042-irregular-rhythm-notification-2018
corpus: regulatory
form factor: watch
creator: U.S. Food and Drug Administration (CDRH); requester Apple Inc.
disclosure: U.S. FDA, De Novo Classification Request DEN180042 (Apple Inc., ‘Irregular Rhythm Notification Feature’), granted 11 September 2018 — decision summary at accessdata.fda.gov/cdrh_docs/reviews/DEN180042.pdf; established a new FDA device classification for software that analyses pulse-rate data from a consumer wrist-worn photoplethysmography sensor, intermittently and in the background, to identify episodes of irregular heart rhythm suggestive of atrial fibrillation and notify the user, with general/special controls.
ip status: regulatory-filing
sensors: sensor-ppg
algorithms: algo-afib-detection, algo-hr
prior art notes: A public, dated FDA decision describing — and creating the device class for — background PPG-based screening for irregular heart rhythm / possible atrial fibrillation on a consumer wrist wearable, with user notification. Establishes as of 11 September 2018 the public availability of: a wrist-PPG device that intermittently analyses pulse-rate variability to flag possible AFib and notifies the wearer. Prior art for later claims to that combination; the decision summary’s account of the algorithm and the Apple Heart Study validation is citable. Pairs with [[apple-watch-series4-ecg-2018]], [[allen-2007-ppg-review]], and the fictional AR-overlay antecedents are irrelevant here — this is enabling prior art.

Apple Watch Series 4 (2018) — wrist single-lead ECG and PPG-based irregular-rhythm notification (2018-09-12)

id: apple-watch-series4-ecg-2018
corpus: private
form factor: watch
creator: Apple Inc.
disclosure: Apple Inc. ‘Apple Watch Series 4’, announced 12 September 2018 (ECG app and irregular rhythm notification feature enabled later in 2018) — a wristworn device taking a single-lead (Lead I) ECG between a back-crystal electrode and a Digital Crown electrode touched by the opposite hand, with on-device AF/sinus classification, plus a PPG-based irregular-rhythm (possible-AF) notification algorithm. FDA cleared via De Novo (ECG app: DEN180044; irregular rhythm notification: DEN180042).
ip status: patented
sensors: sensor-ecg, sensor-ppg
algorithms: algo-afib-detection, algo-arrhythmia-classification, algo-hr
prior art notes: Discloses a wristworn device that records a single-lead ECG between a watch-back electrode and a crown electrode touched by the contralateral hand, classifies the rhythm (AF vs. sinus) on-device, and separately runs a PPG-based background algorithm flagging possible atrial fibrillation. Anticipates wristworn-ECG and watch-AF-detection claims postdating September 2018; the underlying single-lead ECG and PPG-rhythm-screening techniques are much older ([[einthoven-1903-string-galvanometer-ecg]], [[holter-1961-ambulatory-ecg]], [[allen-2007-ppg-review]], [[ieee-11073-10406-basic-ecg-2011]]). Product-side anchor for the watch × ECG and watch × PPG × AF-detection cross-cuts.

Omron HeartGuide (2019) — wristwatch with an inflatable oscillometric blood-pressure cuff in the band (2019-01-08)

id: omron-heartguide-2019
corpus: private
form factor: watch
creator: Omron Healthcare Co., Ltd.
disclosure: Omron Healthcare. ‘HeartGuide’ (model BP8000-M), announced January 2019, FDA-cleared — a wristwatch whose band contains an inflatable cuff and an oscillometric pressure transducer, taking a clinically-validated brachial-style blood-pressure measurement at the wrist on demand, alongside heart rate, steps, and sleep.
ip status: patented
sensors: sensor-pressure-skin, sensor-accelerometer, sensor-ppg
algorithms: algo-hr, algo-step-count, algo-sleep-staging
prior art notes: Discloses a wristwatch whose strap incorporates an inflatable cuff and pressure transducer, performing an oscillometric blood-pressure measurement at the wrist (occlude-and-release, automatically positioned at heart level by the wearer) in a watch form factor, plus activity and sleep tracking. Distinct from cuffless-PPG approaches: it is a true oscillometric cuff miniaturized into a watch band. Anticipates watch-with-integrated-inflatable-cuff BP claims from 2019. Product-side anchor for the watch × oscillometric-BP cross-cut (vs. the cuffless-PPG variant in [[samsung-galaxy-watch-bp-ecg-2020]] and [[aktiia-bracelet-cuffless-bp-2021]]).

Withings ScanWatch (2020) — hybrid analog watch with PPG, SpO2 pulse oximetry, single-lead ECG, and accelerometer (2020-01-05)

id: withings-scanwatch-2020
corpus: private
form factor: watch
creator: Withings SA
disclosure: Withings (Nokia/Withings). ‘ScanWatch’, announced January 2020 (CE-marked 2020; FDA cleared 2022) — a hybrid analog wristwatch integrating a reflectance-PPG sensor (heart rate, irregular-rhythm screening), an SpO2 (pulse-oximetry) measurement, a single-lead ECG (back electrode plus a bezel electrode touched by the opposite hand, with AF detection), a 3-axis accelerometer, and an altimeter — with sleep and activity tracking.
ip status: patented
sensors: sensor-ppg, sensor-spo2, sensor-ecg, sensor-accelerometer, sensor-barometer
algorithms: algo-hr, algo-spo2-estimation, algo-afib-detection, algo-arrhythmia-classification, algo-sleep-staging, algo-step-count, algo-respiratory-rate
prior art notes: Discloses a wristwatch combining reflectance-PPG heart rate, pulse-oximetry SpO2, a single-lead ECG with AF detection, accelerometry, and an altimeter, with sleep-apnea screening (from the SpO2/respiration signals) — multiple regulated cardiorespiratory measurements in one consumer watch. Anticipates multi-modal medical-smartwatch claims reciting combinations of wrist PPG-HR + wrist SpO2 + single-lead ECG from 2020. Product-side anchor for the watch × {PPG, SpO2, ECG} multi-sensor cross-cut.

Samsung Galaxy Watch3 / Samsung Health Monitor (2020) — wrist single-lead ECG and optical-PPG cuffless blood pressure (2020-08)

id: samsung-galaxy-watch-bp-ecg-2020
corpus: private
form factor: watch
creator: Samsung Electronics Co., Ltd.
disclosure: Samsung Electronics. ‘Samsung Health Monitor’ app on Galaxy Watch3 / Watch Active2, 2020 — wrist single-lead ECG (between a back-crystal electrode and a side-button electrode touched by the opposite hand, with AF/sinus classification) and a cuffless blood-pressure feature using the optical (PPG) pulse-wave signal calibrated against a periodic conventional cuff reading. (Cleared in Korea 2020; subsequently in other markets.)
ip status: patented
sensors: sensor-ecg, sensor-ppg, sensor-cuffless-bp-ptt
algorithms: algo-afib-detection, algo-arrhythmia-classification, algo-pwv-bp-estimation, algo-hr
prior art notes: Discloses a wristworn device that takes a single-lead ECG with on-device AF classification and, separately, estimates blood pressure from the wrist optical-PPG pulse waveform after calibration against a periodic conventional cuff measurement (a calibrated-cuffless approach). Anticipates wrist-cuffless-BP claims reciting ‘estimating blood pressure from a wrist photoplethysmography signal calibrated by a reference cuff reading’ from 2020 — the underlying PTT/PWV-BP technique is much older ([[geddes-1981-pulse-transit-time-bp]], [[mukkamala-2015-ptt-cuffless-bp-review]]). Product-side anchor for the watch × cuffless-BP cross-cut.

Bangle.js 2 (Espruino, 2021) — open JavaScript-app smartwatch validated in academic research (2021)

id: bangle-js-2-2021
corpus: open
form factor: watch
creator: Pur3 Ltd. (Gordon Williams, Espruino)
disclosure: Espruino / Pur3 Ltd. ‘Bangle.js 2’, released 2021 — Nordic nRF52840 (ARM Cortex-M4), GPS, heart rate, 3-axis accelerometer, magnetometer, pressure sensor; 4-week battery life; JavaScript app development with web-based app loader. https://banglejs.com . Validated for step counting and heart-rate measurement in academic research (multi-subject MDPI study).
ip status: open-permissive
sensors: sensor-ppg, sensor-accelerometer, sensor-magnetometer, sensor-barometer
algorithms: algo-hr, algo-step-count, algo-activity-classification
prior art notes: Discloses an open-hardware smartwatch with PPG + IMU + magnetometer + barometer + GPS, web-loaded JavaScript apps, and 4-week battery life — validated against reference devices in peer-reviewed studies for step counting and HR. As open-source hardware released in 2021 it is unencumbered prior art against patents reciting the open-firmware-platform smartwatch with this sensor set.

Open-Watch (Salar Motlaqolahi, 2021) — fully documented open STM32 smartwatch (BSc thesis) (2021)

id: smotlaq-open-watch-2021
corpus: open
form factor: watch
creator: Salar Motlaqolahi
disclosure: Motlaqolahi S. ‘Open-Watch’ — fully open-source smartwatch released as BSc thesis output (MIT license). Hardware: STM32 ARM Cortex-M MCU, MPU6050 6-axis IMU, MAX30102 reflectance PPG + SpO2, 4-layer PCB sponsored by PCBWay, full schematics + Gerbers + firmware published. https://github.com/SMotlaq/open-watch
ip status: open-permissive
sensors: sensor-ppg, sensor-spo2, sensor-accelerometer, sensor-gyroscope
algorithms: algo-hr, algo-spo2-estimation, algo-step-count
prior art notes: Discloses, as an MIT-licensed open-hardware smartwatch with full PCB design files (4-layer, PCBWay-sponsored fabrication) and firmware published, a wrist-worn device with reflectance PPG + SpO2 + 6-axis IMU + MCU + display. Demonstrates that the entire smartwatch design — schematic, layout, firmware — can be reproduced from undergraduate-thesis-level public work, defeating any claim that the integrated smartwatch is novel as a combination.

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.

H-Watch (Magno et al., 2024) — open-source ARM Cortex-M4F + ML + NB-IoT + energy-harvesting research smartwatch (2024)

id: h-watch-magno-2024
corpus: academic
form factor: watch
creator: Michele Magno et al. (ETH Zürich and collaborators)
disclosure: Magno M, et al. ‘H-Watch: A Multi-Sensor Smart Wearable for COVID-19 Symptom Monitoring with ML and Energy Harvesting.’ arXiv:2407.21501 (2024). Fully open-source smartwatch hardware + firmware for symptom monitoring: ARM Cortex-M4F MCU, on-device ML inference, NB-IoT cellular connectivity, integrated energy harvesting + battery. https://arxiv.org/abs/2407.21501
ip status: public-domain
sensors: sensor-ppg, sensor-spo2, sensor-skin-temperature, sensor-accelerometer
algorithms: algo-hr, algo-spo2-estimation, algo-respiratory-rate, algo-activity-classification
prior art notes: Discloses a fully open-source research smartwatch combining multi-sensor vitals (PPG/SpO2/temperature/IMU), on-device ML inference, NB-IoT direct cellular connectivity (no phone required), and integrated energy harvesting to extend battery life — published with full hardware design and firmware. Prior art for symptom-monitoring smartwatch claims reciting any of those elements from 2024. Establishes that the cellular-connected open-hardware ML-enabled smartwatch is a published research design.

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.

Intersection cross-cut: watch ∩ sensor-ppg