Intersection cross-cut: sensor-ecg ∩ algo-pwv-bp-estimation

Axes: sensors × algorithms

4 corpus entries disclose both tags.

Earliest disclosure: 1981-01

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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Geddes et al. (1981) — pulse transit time as an indicator of arterial blood pressure (1981-01)

• id: geddes-1981-pulse-transit-time-bp
• corpus: academic
• form factor: other
• creator: Leslie A. Geddes et al. (Purdue)
• disclosure: Geddes LA, Voelz MH, Babbs CF, Bourland JD, Tacker WA. ‘Pulse transit time as an indicator of arterial blood pressure.’ Psychophysiology 1981;18(1):71-74.
• ip status: public-domain
• sensors: sensor-ecg, sensor-ppg, sensor-cuffless-bp-ptt
• algorithms: algo-pwv-bp-estimation
• prior art notes: Establishes that pulse transit time — the delay between a proximal timing reference (e.g. the ECG R-wave) and the arrival of the pulse at a distal site (e.g. a finger PPG) — varies inversely with arterial blood pressure, and can therefore be used to estimate BP without a cuff. Any cuffless-BP wearable claim reciting ‘estimating blood pressure from a pulse transit time (or pulse arrival time / pulse wave velocity) derived from two physiological signals’ reads on Geddes 1981. Earliest anchor for the PTT-cuffless-BP cross-cut; [[mukkamala-2015-ptt-cuffless-bp-review]] is the modern survey.

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]].

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.

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.