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Topic: Problem with MSGEQ7 and Arduino (Read 726 times) previous topic - next topic



Following this tutorial (http://www.uduino.com/Tutorials/7) I hooked up an Uno with a MSGEQ7 display filter IC. Using his code:

Code: [Select]
int analogPin = 0; // read from multiplexer using analog input 0
int strobePin = 2; // strobe is attached to digital pin 2
int resetPin = 3; // reset is attached to digital pin 3
int spectrumValue[7]; // to hold a2d values

void setup()
pinMode(analogPin, INPUT);
pinMode(strobePin, OUTPUT);
pinMode(resetPin, OUTPUT);

digitalWrite(resetPin, LOW);
digitalWrite(strobePin, HIGH);

Serial.println("MSGEQ7 test by J Skoba");

void loop()
digitalWrite(resetPin, HIGH);
digitalWrite(resetPin, LOW);

for (int i = 0; i < 7; i++)
digitalWrite(strobePin, LOW);
delayMicroseconds(30); // to allow the output to settle
spectrumValue[i] = analogRead(analogPin);

// comment out/remove the serial stuff to go faster
// - its just here for show
if (spectrumValue[i] < 10)
Serial.print(" ");
else if (spectrumValue[i] < 100 )
Serial.print(" ");
Serial.print(" ");

digitalWrite(strobePin, HIGH);

See pics for breadboarding and setup. I'm using my iPhone for audio input, and I've verified that I am using the ground and the left channel.

All I get is a repeat of the same numbers:

803 803 798 803 803 803 802
803 803 802 803 802 803 803
803 803 800 803 803 802 803
799 803 802 803 802 804 802
804 803 802 801 803 804 803
803 803 802 803 804 797 804
802 803 803 803 803 799 803
804 801 802 802 803 801 803
803 800 803 801 803 803 803
803 802 802 802 803 803 803
804 803 804 803 803 801 804
804 803 803 804 801 803 803

When I remove the wires for audio input the readout does not change. What am I doing wrong here?


What's the sound your sampling fixed tone or a song


Song, so I was hoping to see a lot of variance in the readings.

James C4S

You might have blown the input to the chip.  I would have suggested a 22k resistor before the capacitor on the input, to help limit the input.
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com


I don't remember the wiring offhand to see if thaats right, but I remember when I first starting playing around with the msgeq7 the biggest problem was miswiring, aalso I couldn't tell from the pic but make sure the audio source ground is connected properly
do you have an a small speaker you can connect to the audio source using the same connections? Idk how you connected to it but sometimes if you just cut the cord off eearphones that wire is enameled and maybe its not connected well enough, if you have an oscilloscope take a look at the audio while its connected as well as the output of the msgeq7 and see if it doesn't match the arduinos serial output


Also idk how much experience you have with breadboards or the specs on that one but make sure the rails are connected all the way across, I notice to get a ground from the middle of the rail and usually the rails are actually separated in groups


I have this identical problem.  I'm wondering if OP found a solution.


You might have blown the input to the chip.  I would have suggested a 22k resistor before the capacitor on the input, to help limit the input.
Input of the audio or input of the 5V?
I want to do a similar project using following scematic, but there's no 22k before audio input too there and I don't want to blow my chip up:

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