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Electret Microphone Amplifier - MAX4466 with Adjustable Gain
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Please be positive and constructive with your questions and comments.

Electret Microphone Amplifier - MAX4466 with Adjustable Gain

by ddevening on Wed Dec 17, 2014 5:06 pm

I don't think my Microphone Amplifier - MAX4466 https://www.adafruit.com/product/1063 is working. I have built the
https://learn.adafruit.com/led-ampli-tie, https://learn.adafruit.com/piccoloand, https://learn.adafruit.com/adafruit-microphone-amplifier-breakout. None of the project show similar results as the videos for the projects. I get almost the same results whether the Microphone Amplifier - MAX4466 is plugged in or not. I have tried to adjust the gain, with no different results. How can I tell if the Microphone Amplifier - MAX4466 is working correctly?

I have attached a photo of how I have it wired for the https://learn.adafruit.com/led-ampli-tie. I have updated the code to use PIN6 for the LED and PIN A0 for the Mic.
Attachments
2014-12-17 13.50.57.jpg
2014-12-17 13.50.57.jpg (180.45 KiB) Viewed 2385 times

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by adafruit_support_mike on Wed Dec 17, 2014 11:21 pm

Try putting a large capacitor between the VCC and GND rails on the breadboard.

Right now you have an analog circuit (the amplifier) connected to the same power supply as a very noisy digital system (the NeoPixel strip). You're probably getting noise from the LEDs in the audio output from the mic.

To test the mic, try disconnecting power to the NeoPixel strip and print the analog input values to the serial monitor with Serial.print(). That will give us a better idea of what the mic is doing.

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by trault on Wed Feb 11, 2015 10:51 pm

I am trying to do the same Ampli-Tie project and am having trouble with the MAX4466. As you suggested I have disconnected the LEDs and hooked up the microphone only and am printing the input. I have checked my circuit and program by testing the 5V and 3.3V pins, The reading on the output pin of my MAX4466 is a constant 0.15V no matter the amount of noise I make. Where is the "adjustable gain"? maybe that is my problem?

Thanks!

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by franklin97355 on Wed Feb 11, 2015 11:26 pm

trault, what are the readings printed out in the serial monitor? Could you post clear, detailed pictures of both sides of your board showing any soldering you have done and the connections to it?

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by trault on Thu Feb 12, 2015 12:01 am

Thank you for the help!

The serial monitor shows 0.26 pretty consistently.

Here is the code:
Code: Select all | TOGGLE FULL SIZE
/*
  ReadAnalogVoltage
  Reads an analog input on pin 0, converts it to voltage, and prints the result to the serial monitor.
  Attach the center pin of a potentiometer to pin A0, and the outside pins to +5V and ground.
 
 This example code is in the public domain.
 */

// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input on analog pin 0:
  int sensorValue = analogRead(A0);
  // Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
  float voltage = sensorValue * (5.0 / 1023.0);
  // print out the value you read:
  Serial.println(voltage);
}
Attachments
Max4466 edge.jpg
Max4466 Edge
Max4466 edge.jpg (342.07 KiB) Viewed 2318 times
Max4466 front.jpg
Front
Max4466 front.jpg (589 KiB) Viewed 2318 times
Max4466 Back.jpg
Back
Max4466 Back.jpg (339.84 KiB) Viewed 2318 times
Last edited by franklin97355 on Thu Feb 12, 2015 1:40 am, edited 1 time in total.
Reason: Added missing [code]...[/code] tags

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by trault on Thu Feb 12, 2015 12:04 am

wiring
Attachments
Max4466 Wiring 2.jpg
Max4466 Wiring 2.jpg (801.2 KiB) Viewed 2318 times

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by ddevening on Thu Feb 12, 2015 11:27 am

@trault, What I ended up doing was using a different power source for the LEDs, then the project started to work. I did not have any capacitors. The lights were bouncing to the music. I will be trying the LED Tie project later, to see if I can get it to work with a battery and the a few LEDs.

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by trault on Fri Feb 13, 2015 11:19 pm

Hi, I still need help troubleshooting the max4466. I posted pics of the front and back. I even resoldered the connections and tested for conductance to make sure there was no short and that the connections were good.

Also, how do I turn the gain "all the way up?"

Thanks, Mike

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by adafruit_support_mike on Sat Feb 14, 2015 12:15 am

If you're getting 0.26v as output, that's a sign of something wrong in the amp. The no-response voltage should be somewhere around 1.65v.

The solder joints in the photos above show some horns, which is usually a sign that you need more flux, but they should conduct well and there's no sign of a short between the pins.

Send a note to support@adafruit.com with a link to this thread and the folks there will get you a new mic breakout (#1063).

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by branhamr on Thu Mar 12, 2015 5:13 pm

I seem to have one of the same batch of Mic Amplifiers. I have replaced all of the other components in the circuit, just ran the test with only the 1063 connected and get a steady string of "15"s on the serial port, no matter where gain is set and ambient sound level.

Tried it with a Duemil., and two Nanos, and two different NeoPixel strings, and a different breadboard. Circuit works OK with a pot in place of the mike signal, but with the mike in place, just a fixed lighted string of pixels.
Attachments
MicAmp.jpg
MicAmp.jpg (401.23 KiB) Viewed 2130 times

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by adafruit_support_mike on Fri Mar 13, 2015 1:04 am

What do you get when measuring the voltage directly between the GND and OUT pins?

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by branhamr on Fri Mar 13, 2015 6:01 am

I apologize for my previous post. My brain was fried yesterday and I jumped to a bad conclusion based on bad data. The 1063 is OK, I just get confused easily at my age. Sorry.

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by adafruit_support_mike on Fri Mar 13, 2015 10:23 pm

Not a problem. Glad to hear it's working for you.

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by Fream476 on Sun Apr 19, 2015 3:17 pm

Hello,

I have a similar issue on my 1063. It work for a couple of day when I was testing with some Arduino code. I have been rattling my brain around what is the problem and can't figure out what is the problem... until I found this post. When I measure the dc voltage between GND and OUT I read a steady 1.65v. I get almost steady reading from the A0 pin on the Arduino regardless of the noise level. What can I do to test proper functionality of the breakout?

adafruit_support_mike wrote:If you're getting 0.26v as output, that's a sign of something wrong in the amp. The no-response voltage should be somewhere around 1.65v.

The solder joints in the photos above show some horns, which is usually a sign that you need more flux, but they should conduct well and there's no sign of a short between the pins.

Send a note to support@adafruit.com with a link to this thread and the folks there will get you a new mic breakout (#1063).

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Re: Electret Microphone Amplifier - MAX4466 with Adjustable

by adafruit_support_mike on Sun Apr 19, 2015 7:01 pm

1.65v is a normal output voltage for a MAX4466 running from a 3.3v supply.

Post a photo of your hardware and connections and we'll take a look.

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Please be positive and constructive with your questions and comments.