Analog MEMS Microphone (VM2020) Hookup Guide

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Contributors: QCPete, bboyho
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Introduction

Note: This tutorial covers the SparkFun Analog MEMS Microphone - VM2020 (BOB-21537). While this tutorial was based on the previous MEMS microphone tutorials, this version of the MEMS microphone is a differential microphone and was designed for noisy environments. For specific details regarding the microphone ICs, refer to the Documents tab on their product pages or the previous release of this Hookup Guide:

The SparkFun Analog MEMS Microphone Breakout makes it easy to work with the Vesper VM2020 analog microphone. The VM2020 is an ultra-high Acoustic Overload Point (AOP), high dynamic range, differential analog output piezoelectric MEMS microphone. What separates this from other analog MEMS microphones is that it was designed to be used in loud environments.

SparkFun Analog MEMS Microphone Breakout - VM2020

BOB-21537
Retired

Read this guide to get an overview of the breakout board and how to use it, including its technical specifications, how to hook it up to a microcontroller, and example code to get started!

Required Materials

To follow along with this tutorial, you will need the following materials at a minimum. You may not need everything though depending on what you have. Add it to your cart, read through the guide, and adjust the cart as necessary.

Arduino Microcontroller

You'll want a microcontroller to power the microphone. We will be using the ESP32 WROOM.

SparkFun Thing Plus - ESP32 WROOM (USB-C)

SparkFun Thing Plus - ESP32 WROOM (USB-C)

WRL-20168
$24.95
3
SparkFun Thing Plus - ESP32 WROOM (Micro-B)

SparkFun Thing Plus - ESP32 WROOM (Micro-B)

WRL-15663
$22.50
13
SparkFun IoT RedBoard - ESP32 Development Board

SparkFun IoT RedBoard - ESP32 Development Board

WRL-19177
$29.95
7

Amplifier and Differential ADC Converter

Since the analog pins on an Arduino microcontroller are usually single-ended, you will need a way to amplify the signal to a reasonable level. You will also need an differential ADC converter. We recommend using the audio codec breakout WM8960. The audio codec can amplify the signal to a reasonable level and already has input pins for a differential microphone.

SparkFun Audio Codec Breakout - WM8960 (Qwiic)

SparkFun Audio Codec Breakout - WM8960 (Qwiic)

BOB-21250
$17.95
1

Tools

Building a circuit using this breakout requires some assembly and soldering. You may already have a few of these items but if not, the tools and hardware below help with that assembly.

Hook-Up Wire - Assortment (Stranded, 22 AWG)

Hook-Up Wire - Assortment (Stranded, 22 AWG)

PRT-11375
$22.50
19

SparkFun Beginner Tool Kit

TOL-14681
Retired

Prototyping Accessories

Depending on your setup, you may want to use IC hooks for a temporary connection. However, you will want to solder header pins to connect devices to the plated through holes for a secure connection. Depending on your application, you could use straight headers or right angle headers. Of course, you could also solder wire as well.

Breadboard - Self-Adhesive (White)

Breadboard - Self-Adhesive (White)

PRT-12002
$5.50
48
Break Away Headers - Straight

Break Away Headers - Straight

PRT-00116
$1.75
20
IC Hook with Pigtail

IC Hook with Pigtail

CAB-09741
$5.50
10
Break Away Male Headers - Right Angle

Break Away Male Headers - Right Angle

PRT-00553
$2.25
5
Jumper Wires Premium 6" M/M Pack of 10

Jumper Wires Premium 6" M/M Pack of 10

PRT-08431
$4.50
2

Recommended Reading

To successfully use the SparkFun MEMS microphone breakout board, you'll need to be familiar with Arduino microcontrollers, analog (aka ADC) input, and sound waves. For folks new to these topics, check out the following resources to get a feel for the concepts and verbiage used throughout this tutorial.

Installing Arduino IDE

A step-by-step guide to installing and testing the Arduino software on Windows, Mac, and Linux.

Analog vs. Digital

This tutorial covers the concept of analog and digital signals, as they relate to electronics.

IoT RedBoard ESP32 Development Board Hookup Guide

Delve into the functionality-rich world of the IoT RedBoard ESP32 Development Board!

Audio Codec Breakout - WM8960 Hookup Guide

The SparkFun Audio Codec Breakout - WM8960 is a low power, high quality stereo codec chock full of features. In this tutorial, some of these features by using an Arduino microcontroller to configure the audio codec and pass audio to the headphone or speaker channels.

Hardware Overview

The SparkFun Analog MEMS microphone breakout board breaks out the microphone for sound detection in loud environments. Each version breaks out the VM2020 on the top side of the board.

top view of  Analog MEMS Microphone - VM2020

The board receives audio input from the bottom of the board. For users soldering straight headers, you may want to consider soldering them from the back.

bottom view of Analog MEMS Microphone - VM2020

  • OUT− - Audio signal output for differential −output.
  • OUT+ - Audio signal output for differential +output.
  • VCC - Voltage input (1.6V to 3.6V). To power this lil' mic, use a DC voltage with a supply current of about 248μA for VM2020. We'll be using 3.3V from an Arduino.
  • GND - Ground.

For technically-minded folks, here are some of the features of the VM2020 and a comparison with other SparkFun MEMS Microphone Breakout boards. Make sure to check out VM2020 datasheet in the Resources & Going Further for a complete overview of the microphone.

Electrical Characteristics ICS-10480 SPH8878LR5H-1 VM2020
High Signal-to-Noise Ratio ("SNR") 65dbA 67dBA 50dbA
Sensitivity about -38dBV about -44dBV about -63dBV
Flat Frequency Response 60Hz to 20kHz 7Hz to 36kHz 80Hz to 10kHz
Low Current Consumption <260 μA @ 3.3V <265 µA @ 3.6V <248 μA @ 3.6V
Acoustic Overload Point (AOP) 124 dB 134 dB 152 dB

Note that the acoustic overload point of the VM2020 is greater than the other MEMS microphones. The audio is less likely to be clipped in louder settings (such as concerts, dance studios, etc.) or when the microphone is placed beside a speaker. Below is a table of typical sounds, their approximate decibel levels, and the AOP of the three microphones listed earlier. The information was gathered from a variety of sources online. Keep in mind noise-induced hearing loss varies depending on the sound intensity, the amount of exposure time, and how close your ears are to the sound source.

Sound Source Approximate Decibel Level [dB] Sound Intensity Microphone Type
Rocket Launch 180 Death of Hearing Tissue
Shotgun Blast 165
Firecrackers 150 Reaching VM2020 AOP
Jet Engine 140 Harmful
Jackhammer 130 Reaching SPH8878LR5H-1 AOP
Car Siren 120 Reaching ICS-10480 AOP
Rock Concert 115
Lawn Mower 90 Risk of hearing loss when sustained levels of 90dB
Loud City Traffic 85 Sounds above 85dB are harmful
Normal Conversation 60
Quiet 0 Normal Hearing Threshold

Board Dimensions

The board dimensions for the breakout are 0.40" x 0.55" (10.16mm x 13.97mm). The location of the header pins are different compared to previous versions with the extra pin for the differential output.

Board Dimensions

Hardware Hookup

Now that we're familiar with the microphone breakout, let's connect it to a microcontroller and monitor some sound!

Microphone Breakout Connections

For a permanent connection, we recommend soldering four wires (or headers) to the PTHs on the breakout. We opted for soldering header pins and using jumper wires. Of course, you could also solder wires to the breakout board as well. For a temporary connection during prototyping, you can use IC hooks like these.

How to Solder: Through-Hole Soldering

September 19, 2013

This tutorial covers everything you need to know about through-hole soldering.

Working with Wire

February 8, 2013

How to strip, crimp, and work with wire.

We recommend soldering right angle headers. Right angle headers will provide a low height profile. This is more versatile as users can angle the microphone or add M/F jumper wires between the board and breadboard. The microphone will also sit up and away from the board.

alt text

Connecting to a Microcontroller and Audio Codec WM8960

Next up we'll connect the breakout to an audio codec to amplify and read the signal. Then we will connect the boards to a microcontroller to monitor the audio signal output. For this tutorial, we used the MEMS microphone with the audio codec WM8960 and SparkFun IoT RedBoard - ESP32. The ESP32 module has I2S support and is recommended in this setup with the WM8960. Make the following connections between the breakout and IoT RedBoard - ESP32 (or whichever ESP32 variant that you choose).

IoT RedBoard - ESP32 (or Arduino) MEMS Microphone WM8960 TRS Connector
5V VIN
Qwiic Cable's SCL pin
(or SCL)
Qwiic Cable's SCL pin
(or SCL)
Qwiic Cable's SDA pin
(or SDA)
Qwiic Cable's SDA pin
(or SDA)
Qwiic Cable's 3.3V pin
(or 3.3V)
Qwiic Cable's 3.3V pin
(or 3.3V)
Qwiic Cable's GND pin
(or GND)
Qwiic Cable's GND pin
(or GND)
Output − LIN1
Output + LIN2
GND GND
VCC AVDD
(i.e. 3.3V)
25 ALRC
17 ADAT
16 BCLK
HPL TIP
OUT3 GND (i.e. Sleeve)
HPR RNG (i.e. Ring)

The completed circuit should look something like the photo below:

Fritzing Diagram

Software Installation

Note: This example assumes you are using the latest version of the Arduino IDE on your desktop. If this is your first time using Arduino, please review the following tutorials.

Arduino Board Definitions and Driver

We'll assume that you installed the necessary board files and drivers for your development board. In this case, we used the IoT RedBoard - ESP32 which uses the CH340 USB-to-serial converter. If you are using a Processor Board, make sure to check out its hookup guide for your Processor Board.

Installing Board Definitions in the Arduino IDE

September 9, 2020

How do I install a custom Arduino board/core? It's easy! This tutorial will go over how to install an Arduino board definition using the Arduino Board Manager. We will also go over manually installing third-party cores, such as the board definitions required for many of the SparkFun development boards.

IoT RedBoard ESP32 Development Board Hookup Guide

August 18, 2022

Delve into the functionality-rich world of the IoT RedBoard ESP32 Development Board!

How to Install CH340 Drivers

August 6, 2019

How to install CH340 drivers (if you need them) on Windows, Mac OS X, and Linux.

Installing the Arduino Library

We'll be using the WM8960 audio codec and connecting to the differential microphone input pins. The SparkFun Arduino library can be downloaded with the Arduino library manager by searching 'SparkFun Audio Codec Breakout WM8960' or you can grab the zip here from the GitHub repository to manually install.

Arduino Example

Note: We used espressif's v2.0.6 board package for the SparkFun IoT RedBoard - ESP32. Previous versions of the board package seem to save the channels differently in the buffer. When reading the WM8960's I2S left microphone channel with v2.0.5 and this example, the Serial Plotter would only display the "right channel."

From the menu, select the following: File > Examples > SparkFun WM8960 Arduino Library > Example_15_VolumePlotter_MEMS_Mic_Differential. If you have not already, select your Board (in this case the SparkFun ESP32 IoT RedBoard), and associated COM port. Then hit the upload button.

Open the Arduino Serial Plotter and set it to 115200 baud to view the output. Make some noise by saying "Woooo!," clapping, or rubbing your fingers on the microphone. You should see an output showing the left input microphone's audio signal!

Arduino Serial Plotter Output from the Left Microphone Channel Input

Try placing the microphone next to a loud amplified speaker and adjusting the PGA as necessary for your application. Or add a second MEMS microphone to the right channel and adjusting code to include the right channel.

Note: To adjust the code to include the right channel as well, you will need to adjust the mean for both the left and right channels in the if (result == ESP_OK){} statement. You will then need to calculate and plot the values as comma separated values (CSV) for the Arduino Serial Plotter to display properly. Below is how the adjusted code should look like.

  if (result == ESP_OK)
  {
    // Read I2S data buffer
    int16_t samples_read = bytesIn / 8;
    if (samples_read > 0) {
      float meanLeft = 0;
      float meanRight = 0;
      // Only looking at left signal samples in the buffer (e.g. 0,2,4,6,8...)
      // Notice in our for loop here, we are incrementing the index by 2.
      for (int16_t i = 0; i < samples_read; i += 2) {
        meanLeft += (sBuffer[i]);
      }
      
      // Only looking at right signal samples in the buffer (e.g. 1,2,5,7,9...)
      // Notice in our for loop here, we are incrementing the index by 2.
      for (int16_t i = 1; i < samples_read; i += 2) {
        meanRight += (sBuffer[i]);
      }

      // Average the data reading
      // Calculate left input for this example. So we must divide by
      // "half of samples read" (because it is stereo I2S audio data)
      meanLeft /= (samples_read / 2); 
      
      // Calculate right input for this example. So we must divide by
      // "half of samples read" (because it is stereo I2S audio data)
      meanRight /= (samples_read / 2);

      // Print to serial plotter
      Serial.print(meanLeft);
      Serial.print(",");
      Serial.println(meanRight);
    }

Troubleshooting

Resources and Going Further

Now that you've connected your MEMS microphone breakout, it's time to incorporate it into your own project! For more information on the board, check out the resources below:

Need some inspiration for your next project? Check out some of these related tutorials for ideas. Add the Analog MEMS microphone (VM2020) in your project!

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