Microphone
Microphones convert sound pressure into an electrical signal, used in voice interfaces, audio capture, and acoustic monitoring.
Different sensors use different physics: a thermistor changes resistance with temperature; a photodiode produces current under light; a MEMS accelerometer measures the deflection of a tiny silicon spring; an ultrasonic sensor times the round-trip of a click.
In plain terms
Five senses for your microcontroller. Each sensor is one of those senses translated into electricity.
Why designers use it
- Read the environment so firmware can decide what to do.
- Close the loop on motion control or temperature regulation.
- Detect human presence, gestures, or biometric signals.
- Provide telemetry to dashboards and alerts.
Best for
- Environmental monitoring
- Human-machine interfaces
- Industrial control loops
- Health and fitness wearables
Key specifications
- Operating limits: Check the exact manufacturer's datasheet (A family name does not establish voltage, current, temperature or timing limits.)
- Pin assignment: Match the complete part and package code (A similar name or function does not guarantee the same wiring.)
- Mechanical fit: Use the exact package drawing (Check pad layout, dimensions and viewing direction before building.)
When not to use it
- Where a simple switch or threshold would do — sensors add complexity and cost.
- Where firmware can't handle the noise or calibration the sensor demands.
Common mistakes
- Skipping the data-sheet recommended decoupling and seeing noise dominate the measurement.
- Mounting a temperature sensor where the MCU's heat dwarfs the signal.
- Forgetting to calibrate — raw sensor counts ≠ engineering units.
Where you will find it
- A resistive sensing element can be placed in a divider or bridge so its resistance change becomes a measurable voltage.
- A measurement chain may combine a sensor, conditioning electronics and an ADC. Each stage contributes its own limits.
A short history
Shure's historical account describes David Edward Hughes building an early carbon microphone in the 1870s and notes Edison and Berliner's dispute over related patent rights. It credits Hughes prominently rather than presenting one uncontested date for three independent inventions. Carbon microphones became important in telephony; that history is distinct from the later technologies used in modern microphones.