Electret Amplifier Microphone - MAX9814 with auto-gain
Auto-Gain amplified electret microphone
- MAX9814 amplifier
- Microphone 20-20KHz
- Auto gain (automatically adjust the gain).
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Add ears to your project with an auto-gain electret microphone
Having a ear in your project with a 20-20KHz electret microphone amplifier with Auto Gain Control. This well designed board use the Maxim MAX9814 for amplification (specialty designed for electret microphone amplification in situations where the loudness of the audio isn't predictable).
This microphone amplifier breakout is even better with a built in automatic gain control. The AGC in the amplifier means that nearby 'loud' sounds will be quieted (so they don't overwhelm and even quiet) while far-away sounds will be amplified.
This amplifier really good when you need to record or detect audio in situations where the sound levels changes and when you don't want to have to tweak the amplification gain all the time.
The MAX9814 (technical datasheet) amplifier have few options that can be configured with the breakout. The default "max gain" is 60dB (but can be changed to 40dB or 50dB by jumpering the Gain pin to VCC or ground).
You can also change the ratio for the Attack/Release. This ratio is set to 1:4000 by default and can be changed to 1:2000 or 1:500. The amp produce an output of max 2Vpp (peak to peak) with a DC bias of 1.25V DC. This output can feeds directly the analog input of any 3.3V-5V microcontroler. It can also be connected to a digital input if you only need to know the existence of any sound around.
To feed a Line Input, the DC composante must be removed from the signal. Use a 1 to 100µF capacitor in series to bloc DC signal (100uF sounds best).
For audio-reactive projects, it is also possible to use a FFT library (such as the one in this library) which can transform audio input to a series of frequencies. If need to keep track of audio levels then you can check the Adafruit's sound-level meter tutorial for Arduino
Technical details
- Size: 26 x 14 mm
- MAX9814 (technical datasheet)
Content
Each order comes with one assembled and tested board, with electret mic pre-soldered on, and a small piece of header.
Tutorials
- Get started with using and testing the microphone amplifier (Adafruit, English)
- General-purpose microphone amplifier tutorial (Adafruit, English).
- See more tutorials on the Adafruit Product sheet (Adafruit, English)
