Prior to deployment in research or production environments, Hyfe performs pre-flight microphone verification testing to ensure that each device’s acoustic sensing pathway meets engineering specifications required for reliable cough-like event capture. These tests are conducted using a standardized test-rig and controlled acoustic stimuli, enabling precise, repeatable assessment of microphone functionality under well-defined conditions. These tests also confirm the proper functioning of other, non-acoustic components of the device, including those pertaining to connectivity, display, data transmission, battery, and logging. The objective of the pre-flight process is to validate that the sensors can faithfully record cough-like impulsive sounds and maintain performance in the presence of expected environmental noise, thereby confirming their readiness for field use.
The core component of the pre-flight protocol involves exposing devices to synthetic cough-like audio events played through a calibrated loudspeaker system. The stimuli emulate the broadband impulsive spectral characteristics of human coughs, including rapid onset, short duration, and multi-frequency content between approximately 100–3,500 Hz. Playback occurs within an acoustically controlled environment to ensure consistent delivery of sound energy across repetitions.
During testing, devices are placed in standardized orientations and distances relative to the source to eliminate spatial variability. Audio of real-world recorded coughs is played via speakers, and detections are quantified. Devices that do not fall within range are discarded.
To ensure robustness under realistic environmental conditions, Hyfe incorporates ambient-noise exposure testing as an integral component of the pre-flight evaluation. Background noise typical of real-world settings—such as HVAC hum, distant conversation, and broadband environmental noise—is introduced at controlled and repeatable levels.
During this phase, devices are expected to detect a very low number of coughs (false positives). Devices that do not fall within range are discarded.
All pre-flight testing is conducted using a standardized test-rig, engineered to provide consistent, reproducible test conditions and eliminate operator-dependent variability. The test-rig incorporates:
This standardized infrastructure ensures that the verification process is traceable, reproducible, and aligned with established engineering quality practices. The use of a dedicated test-rig strengthens the reliability of pre-flight assessments and provides documented evidence that devices meet design specifications prior to use in research settings.
Integrating controlled playback, ambient-noise robustness testing, and test-rig standardization, Hyfe’s pre-flight microphone verification procedure provides comprehensive confirmation that devices are able to reliably capture cough-like acoustic events with the fidelity required for downstream algorithmic processing. Passing these tests demonstrates that:
In summary, Hyfe’s pre-flight microphone verification ensures that every device undergoes rigorous, standardized testing prior to study deployment, establishing a high level of confidence in microphone integrity and acoustic data quality. This process contributes directly to reliable cough detection performance in real-world and clinical research environments.
Detailed docmentation is available on the testing architecture, the pre-flight checklist, and the test rig itself, below.