• Handheld research and development platform designed toward diagnostic-grade accuracy.
• Used with a patient mask/nasal interface for active anterior rhinomanometry.
• One nostril is sealed and used to sense posterior nasal pressure while airflow through the opposite nostril is measured; sides are then swapped.
• Clinical claims require formal verification, validation, risk management, and regulatory approval beyond PCB development.

• Simultaneously measure bidirectional nasal airflow and differential nasal pressure.
• Capture quiet breathing and stronger voluntary blowing without saturation.
• Stream live synchronized waveforms and status to an Android/iOS device.
• Retain raw pressure and flow data for later analysis.
• Support pressure-flow loops, time-domain plots, breath quality checks, and resistance calculations.
• Operate for at least 4 hours per charge.
• Charge safely from USB-C.

• Active anterior rhinomanometry.
• BLE phone/tablet interface; all test controls reside in the app.
• Simple hardware UI: power control and status indication only.
• Internal rechargeable single-cell Li-ion/LiPo battery.
• Compact, self-contained handheld construction; no separate electronics box.
• Calibration and zero-check workflow for both channels.

Diagram

• Differential measurement target: at least ±1200 Pa.
• Must preserve sensitivity around the historical 75 Pa and 150 Pa operating points.
• Target total channel error: ≤2% full scale, subject to a tighter accuracy budget during sensor selection.
• Pneumatic tubing, leakage, condensation, zero drift, and dynamic response are part of the channel specification.

• Bidirectional range target: at least ±1200 cm³/s (±72 L/min).
• Calibrated flowhead or pneumotach element with characterized pressure drop and linearization.
• Flow path must be compact, cleanable or use replaceable patient-contact components, and resistant to condensation effects.

• Synchronized pressure and flow acquisition.
• Complete channel response target: reliable to 80 Hz.
• Initial digital sampling target: 500 samples/s per channel or higher, subject to verification.
• BLE throughput must carry live raw or lightly processed waveforms without losing samples.
• Secure device identification, connection status, battery reporting, and firmware-update support are expected.

• Measure ambient temperature, relative humidity, and barometric pressure.
• Record environmental conditions with each test.
• Apply documented correction where required by the selected flow-sensing method.

• USB-C 5 V charging input with correct CC configuration and ESD protection.
• Single-cell rechargeable battery with protection, charge management, and power-path operation.
• Low-noise supply architecture suitable for low-pressure measurement and BLE radio bursts.

• Power control.
• Minimal LED/status indication for power, BLE connection, charging, low battery, and fault state.
• Test configuration, live display, patient records, calibration, and analysis handled by the wireless app.

• USB-C: charging, and optionally service/firmware access; no routine wired operation required.
• BLE: Android and iOS application connectivity.
• Patient interface: transparent mask/flowhead and a sealed pressure pickup at the non-flowing nostril.
• Internal programming/debug interface available during development.

• Minimum operating runtime: 4 hours.
• Design target: approximately 6 hours when the battery is new to allow aging and environmental margin.
• Charging may occur while the electronics remain operational only if measurement integrity and patient safety are maintained; diagnostic measurements while connected to external power remain an open regulatory decision.

• Initial prototype, with architecture suitable for later production refinement.
• Compact PCB sized around the pneumatic geometry and enclosure rather than an arbitrary board outline.
• Assembly-compatible SMD components and accessible test points.
• Replaceable or disinfectable patient-contact path; electronics must be isolated from condensate.
• Sensor calibration coefficients and unit serial number stored in nonvolatile memory.

• Continuous synchronized sampling and timestamping.
• BLE services for raw pressure, raw flow, environmental data, battery state, device status, and calibration metadata.
• Local buffering to tolerate short radio scheduling delays.
• Zeroing, span calibration, quality flags, breath segmentation, and dropped-sample detection.
• Firmware update mechanism and development debug access.

• Entire sensing and electronics system in one compact handheld unit; no separate box.
• Only the mask/nasal tips and minimal patient tubing external.
• Flow path and pressure ports positioned to minimize tube length and pneumatic distortion.
• BLE antenna kept clear of battery, shielding, wet flow path, and the user's hand as far as practical.
• Enclosure must prevent liquid/condensate ingress into electronics and allow hygienic handling.

• Published range: ±800 Pa pressure and ±800 cm³/s flow.
• Published accuracy: ±2%.
• Active anterior/posterior, Standard, Broms, Rohrer, Vertex, and Effective resistance methods depending on model.
• Historical active-anterior comparison commonly uses flow at 150 Pa.

• Engineering range target: approximately ±1200 Pa and ±1200 cm³/s.
• Reliable pressure and flow channel response to 80 Hz with maximum error of 2% FSO.
• Display and retain full pressure-flow waveforms rather than relying only on a single resistance point.
• Preserve flow at 150 Pa for historical comparison.
• Capture synchronized pressure-flow time plots and pressure-flow loops.
• Target Effective resistance metrics for complete breath, inspiration, and expiration after algorithm validation.
• Calibration verification and environmental metadata must accompany diagnostic measurements.

• Active anterior rhinomanometry is the primary method.
• Both quiet breathing and forced blowing must be measurable.
• Measurement envelope will exceed the NR6 published range to align with newer consensus guidance.
• BLE is the only routine data/control connection.
• The handheld has no display; only power/status indication.
• Minimum runtime is 4 hours, with a 6-hour new-battery design target.

• A phone/tablet is present during normal use.
• Initial development is a prototype designed toward diagnostic performance, not yet a certified medical device.
• A calibrated pressure-drop flow element is likely preferable to placing an exposed MEMS mass-flow sensor directly in the humid patient stream; final selection requires feasibility testing.
• Disposable filters or flowheads must be included in complete-system calibration if used.
• Exact enclosure size, battery capacity, sterilization strategy, and patient interface geometry remain open.

• No saturation over at least ±1200 Pa and ±1200 cm³/s.
• Static and dynamic channel error demonstrated against traceable references.
• Complete-system response verified through 80 Hz.
• Pressure and flow remain synchronized within a defined timing budget.
• Four-hour minimum runtime demonstrated under continuous streaming.
• BLE streaming operates without sample loss at the selected acquisition rate.
• Repeat measurements on a calibrated model nose meet the defined repeatability target.
• Leak, blocked tube, condensation, sensor saturation, and unstable-zero conditions are detected or flagged.

• Initial specification created from user requirements.
• Added NR6 benchmark and Riga consensus measurement targets.
• Confirmed compact handheld construction, BLE-only controls, USB-C charging, and four-hour minimum runtime.