Description

The MAX9814 microphone amplifier module is a high-performance, low-noise amplifier with built-in automatic gain control (AGC). It is designed for audio applications such as voice detection, sound measurement, and voice-activated systems. The module features a built-in MAX9814 IC, a high-quality electret microphone, and supports adjustable gain control.

Ideal for use with Arduino and other microcontrollers, it provides clean analog audio output, even when the sound level varies greatly.

Features

Built-in MAX9814 amplifier chip
Automatic Gain Control (AGC) for consistent output levels
Wide supply voltage: 2.7V – 5.5V
Adjustable gain: 40dB, 50dB, 60dB (via pin jumper)
Output: Analog audio signal
High sensitivity and low noise
Compact PCB with onboard electret microphone

Getting started with MAX9814 Microphone amplifier Module AGC

In this project we are going to demonstrate how to use the MAX9814 microphone amplifier module with an Arduino to create a sound-reactive LED. The LED’s brightness changes in response to detected sound levels, creating a simple audio visualization effect. Feel free to go beyond this example, even including Machine Learning (ML).

Hardware Requirements

Arduino board (Uno, Nano, or compatible)
MAX9814 microphone amplifier module
LED (built-in or external)
Current-limiting resistor (220-330Ω for external LED)
Breadboard
and jumper wires

Connections

MAX9814 to Arduino:
- OUT → A0
- VDD → 5V
- GND → GND
- GAIN pin settings:
  - Ground (GND) = 40dB gain
  - VDD (5V) = 50dB gain
  - Floating = 60dB gain (default)
LED:
- Connect to a PWM-capable pin (suggested pins: 3, 5, 6, 9, 10, or 11)
- Remember to use a current-limiting resistor (220-330Ω)
- Example: LED positive → pin 9, LED negative → GND via resistor

Project Codes

Cope the codes
Open sketch in Arduino IDE
Upload the sketch to your Arduino board

Installation

max9814 circuit diagram — MAX9814 circuit diagram

max9814 schematic diagram — MAX9814 schematic diagram

Power up your Arduino
The LED will respond to sound:
- Louder sounds = Brighter LED
- Quieter sounds = Dimmer LED
Visualization options:
- Serial Monitor (9600 baud): View raw sensor values
- Serial Plotter (9600 baud): View real-time graphs of:
  - Raw signal (blue)
  - Mapped LED brightness (red)
  - Moving average (green)