SparkFun Sound Detector

The SparkFun Sound Detector is a small and easy-to-use audio sensing board designed to provide versatile sound detection for your projects. Instead of being limited to a single measurement, this board provides three simultaneous and independent outputs. Whether you need to analyse raw audio waveforms, trigger an event based on a sudden loud noise, or simply measure the overall volume level of a room over time, this sensor gives you the exact data you need without requiring complex code or external processing.

Three Independent Outputs

Because the three outputs on this Sound Detector function simultaneously, you can use as many or as few as your application requires. Simply connect the signals you need and leave the unused pins disconnected on the standard 0.1-inch pin-out located at the edge of the board.

• Audio: Outputs the direct, raw analogue voltage straight from the onboard electret microphone.
• Envelope: Provides a smoothed analogue representation of the sound's amplitude, allowing you to easily read the overall volume by measuring the analogue voltage.
• Gate: A binary digital output that indicates the physical presence of sound, making it surprisingly easy to trigger physical hardware when a specific noise threshold is crossed.

Adjustable Sensitivity

While the board is configured to work right out of the box for general room noise, it is customisable to suit your specific environmental requirements. You can easily adjust the amplifier's gain by soldering a standard through-hole resistor to the board. This directly changes the threshold of the binary gate output pin, making it highly adaptable for detecting specific sound levels in either incredibly loud or very quiet environments.

If you would like a Sound Detector with headers already soldered on, be sure to check out this board's sibling.

• Schematic
• Eagle Files
• Datasheet (LMV324)
• Hookup Guide
• GitHub Hardware Repo