Interfacing Microphone Amplifier MAX9814 With Arduino: Complete Guide

Introduction

MAX9814 with Arduino is a powerful combination for audio-related projects that need precise and amplified sound detection. Whether you’re working on voice-activated devices, audio-reactive lighting, or DIY sound meters, the MAX9814 microphone amplifier module offers great performance with automatic gain control (AGC).

In this guide, we’ll explore what the MAX9814 module is, how it works, how to connect it to an Arduino, and provide example code to get you started. We’ll also highlight key differences between MAX9814 and basic sound sensors, and suggest project ideas where it shines.

What is the MAX9814 Microphone Amplifier?

The Adafruit MAX9814 is a high-performance microphone amplifier module that uses an electret microphone and the MAX9814 IC. It includes built-in Automatic Gain Control (AGC), which allows it to dynamically adjust amplification levels depending on the loudness of the sound, making it ideal for environments with variable noise levels.

Max9814_Module — *MAX9814 Microphone Module*

Key Features:

Built-in electret microphone
Low noise amplifier
Automatic Gain Control (AGC)
Configurable gain and attack/release time
Operating Voltage: 2.7V to 5.5V
Analog output

Use case: Voice detection, sound level monitoring, audio visualization, and other sensitive audio input applications.

Max9814 Pinout and Configuration

Here’s a quick reference of the Max9814 module pinout:

Pin	Description
VDD	Power supply (2.7V–5.5V, typically 3.3V or 5V)
GND	Ground
OUT	Analog audio output
AR	Attack/Release control (for AGC timing)
Gain	Selects fixed gain (default 40dB)
VDD (MIC)	Internal connection to power mic bias

AGC and Gain Settings:

You can change the AGC response time by connecting AR to GND or VDD.
The gain pin allows selecting 40dB, 50dB, or 60dB gain via resistor pull-downs.

Connecting MAX9814 with Arduino

Here’s how to connect the MAX9814 to an Arduino Uno for analog audio level reading:

MAX9814 Pin	Arduino Uno Pin
VDD	5V
GND	GND
OUT	A0
AR, Gain	Leave unconnected (use default AGC & gain)

Max9814_with_Arduino_Wiring — *MAX9814 with Arduino Wiring Diagram*

Example Arduino Code: Audio Level Reader

const int micPin = A0;  // Analog pin for MAX9814 output

void setup() {
  Serial.begin(9600);
}

void loop() {
  int micValue = analogRead(micPin);
  Serial.print("Sound Level: ");
  Serial.println(micValue);
  delay(50);
}

This basic code reads analog values from the MAX9814 output. You can use this data to build a real-time sound meter or trigger audio-reactive behavior.

Hardware Setup:

Serial Monitor Output:

Applications of Max9814 with Arduino

Voice-activated switches and assistants
Audio visualizers and VU meters
Sound-level logging for environmental noise
Home automation triggered by sound
DIY voice-controlled robots

Why Use Max9814 Over Basic Sound Sensors?

Feature	MAX9814 Module	Basic Sound Sensor
Audio Output	Analog (clean, amplified)	Analog/Digital (noisy)
AGC Support	Yes	No
Sensitivity	High	Low to Medium
Audio Signal Quality	Excellent	Poor to Average
Price	Slightly higher	Very affordable

The MAX9814 is ideal when you need reliable, high-quality audio input or cleaner analog readings.

Project Idea: Sound Level Meter with OLED Display

Use the MAX9814 module with an I2C OLED display (e.g., SSD1306) to create a real-time audio level meter.

Wiring Overview:

MAX9814 → Arduino A0
OLED Display → SDA to A4, SCL to A5

Libraries Needed:

Adafruit_GFX
Adafruit_SSD1306

Code Snippet:

#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

int micPin = A0;

void setup() {
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
}

void loop() {
  int micVal = analogRead(micPin);
  display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(2);
  display.setCursor(0, 10);
  display.print("Sound Lvl:");
  display.setCursor(50, 40);
  display.print(micVal);
  display.display();
  delay(100);
}

Demo:

Conclusion

If you’re looking for a high-quality audio input module, combining MAX9814 with Arduino provides a simple yet powerful solution. Its AGC, adjustable gain, and clean output make it superior to basic sound sensors for many applications. Start with simple sound level monitoring, then expand into voice-activated or reactive projects for real-world interaction.

💡 Note: This tutorial is based on practical testing and usage of the MAX9814 with Arduino. For in-depth technical details about the internal working of the AGC (Automatic Gain Control) and configuration options, you can refer to the official Adafruit MAX9814 Microphone Amplifier Guide.

Interfacing Microphone Amplifier MAX9814 with Arduino: Complete Guide