Wired sensor head
A small capsule and acoustic housing connect to a separate recording unit. This keeps the sensor compact and gives the power and converter stages more room.
Hardware research · concept stage
Small microphone.
A complete signal path.
For quiet dialogue, microphone self-noise, placement, room sound, and the analog electronics matter alongside digital resolution.
A candidate capsule
Infineon’s IM73A135V01 specifies a 4.00 × 3.00 × 1.20 mm package and 73 dB(A) signal-to-noise ratio. It has a differential analog output and a bottom acoustic port. These are capsule specifications; an enclosure, preamplifier, converter, storage, power supply, and connectors add size.
Manufacturer’s datasheet ↗Self-contained recorder
The capsule, converter, storage, and battery share one enclosure. Required runtime and battery dimensions determine much of the final size.
Proposed engineering baseline
- Uncompressed 24-bit, 48 kHz WAV recording.
- Low-noise differential input with appropriate gain and headroom.
- Wind and handling isolation, plus an acoustically suitable enclosure.
- Measured noise floor, frequency response, clipping level, and battery runtime.
- Clear recording indication and a documented intended use.
Before choosing a board or enclosure, the design needs maximum dimensions, expected distance, runtime, and whether a cable is acceptable. Higher sample rate cannot recover sounds that the microphone did not capture above its noise floor.
Use in Mexico
Authority to record, authority to upload, and authority to disclose are separate questions. Mexican constitutional doctrine distinguishes third-party interception from a participant voluntarily providing a communication; that distinction is not a blanket authorization for every recording or disclosure. Confidentiality duties, privacy, purpose, and the circumstances can affect the result.
Reference: SCJN thesis 2013199. A specific intended use should be checked against current applicable law.