The Adafruit Electret Microphones with Adjustable Gain Amplifier feature a built-in microphone and use the MAX9814 microphone amplifier chip. There's a small trimmer pot on each one to adjust the gain between 25x and 125x so that you can minimise volume related distortion. They can be supplied with 2.4 to 5V DC and are capable of rail to rail output with a DC bias of Vcc/2. Be careful when selecting your power supply, 5Vpp may offend the Line Input of a standard amplifier for example. If you want to connect one to a Line Input then use a blocking capacitor of between 1 and 100µF unless you have a differential amplifier or it already has its own blocking capacitor.
Adafruit recommend using a low-noise 3.3V DC supply if you intend connecting these amplifiers to an analogue to digital converter (ADC). In this application there's no need for a blocking capacitor.
Visit http://learn.adafruit.com to get started quickly using Adafruit's tutorial for this microphone amplifiers showing how to wire them up to headphones. Having mastered that, you can move on to connecting one to a microcontroller. Adafruit have a tutorial and FFT library for the Arduino which extracts frequency information from the audio and another which is a sound level tutorial.
Supplied with a fully assembled amplifier board, and a strip of 0.1in. header pins for you to solder on if required.
- Electret mic with amplifier
- Adjustable gain 25x to 125x
- Adafruit part no.: 1063
*Customers looking to resell on eBay or Amazon should contact Adafruit directly.
