Sound Detector - LMV324

Sparkfun ElectronicsSKU: RB-Spa-913
Manufacturer #: SEN-12642

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Sale price ¥2,054

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  • Small and easy to use audio sensing board with 3 different outputs
  • Provides binary indication of sound and analog representation of amplitude
  • 1.2MHz gain bandwidth
  • RoHS compliant

The Sound Detector - LMV324 is a small and very easy to use audio sensing board with three different outputs. The sound detector not only provides an audio output, but also a binary indication of the presence of sound, and an analog representation of its amplitude. The 3 outputs are simultaneous and independent, so you can use as many or as few as you want at once. The envelope output allows you to easily read amplitude of sound by simply measuring the analog voltage. Gain can be adjusted with a through-hole resistor, to change the threshold of the binary (gate) output pin as well. Each of the three output signals is present on the .1" header at the edge of the board. They are active simultaneously. If you aren't using one in your particular application, simply leave that pin disconnected.

Sound Detector - LMV324

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Customer Reviews

Based on 2 reviews
not a mature product

Doesnt work properly even on a stabilized power supply. High distortion noise on the audio output signal obviously prevents the circuit from delivering high quality output signals. And even the range for power supply is very narrow form lets say 4.5 V to approx. 7 V. On an USB-Power supply the device gets "unstable", does not work at all. Periodic very high distortion signal on the audio output and gate always on high. Really, such a simple device can be built with constructions sets from years 2000 and following based on LMV324. Sparkfun: Please add features to prevent high frequency input noise supression and make the circuit more stable for the power supply. Now I bought a device for 3 EUR. Much cheaper and more reliable.

An excellent, easy to use, board for triggering on acoustic events.

I'm using this board to acoustically trigger my high-speed camera (a Chronos 1.4). This is an inexpensive, accurate, and easy to build solution useful for initiating an event upon a clap, bang, or other coincident sounds. This board is able to output a TTL-compatible pulse (from GATE) when it detects a sound. I powered the board with three AA batteries = 4.5 V at GND and VCC). The sensitivity of the board as shipped was suitable for my work, but, you can adjust the sensitivity (so it detects louder or softer sounds) by adding/removing an onboard resistor (marked GAIN=R17 and R3). The GATE output is a TTL pulse with a duration equal to the duration of the sound envelope of the input. The two other outputs are useful if you want to capture the oscillogram (AUDIO) or the ENVELOPE (which is a low-pass filtered version of the oscillograph). I can tell you that the oscillographic output is not necessarily a high-fidelity capture of the input waveform, but, I can see how it can be useful for many projects. It’s quite a versatile and robust board. My plan is to incorporate this into a nice project case with BNC output so I can easily cable it to my camera in the future. You can find additional documentation about this board easily online.

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