Has anyone had success hooking up a Sparkfun electret mic breakout ( https://www.sparkfun.com/products/9964 )

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Has anyone had success hooking up a Sparkfun electret mic breakout (https://www.sparkfun.com/products/9964) to an MSEQ-7? Do you have a schematic?

I’ve just breadboarded an example circuit (http://nuewire.com/info-archive/msgeq7-by-j-skoba/) and I’m getting odd results—all values for each channel +/- 3 of each other within each read, but different values in subsequent reads.

There’s an Electronics Stackexchange post (http://electronics.stackexchange.com/questions/71873/why-is-my-msgeq7-circuit-giving-arduino-analog-readings-that-are-so-high) with a similar issue that suggests the op-amp output of the Sparkfun board might be too “hot” for the MSEQ-7 but their symptoms were somewhat different to mine—and in any case, the remediation suggested (build a band-stop filter out of a bunch of passives) isn’t great for my application, as I’m already space constrained.

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I actually preferred their MEMS microphone. Can’t recall the results with this one. Did you connect AREF to 3.3V? and add the following to setup()

analogReference(EXTERNAL);

however it looks like you’re adding that to the MSGEQ7, so I don’t know the difference in voltages. I just thew it directly onto an analog pin.

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The mic is on 5V, I’ll try it on the Teensy’s 3.3V/AREF—but does that mean the VCC of the MSEQ-7 should be 3.3V too, or still on the 5V?

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Hi @Robert_Atkins ,
I started playing with the MSEQ7 and an electret microphone with a small LM386 based audio amplifier board last year as I wanted to add music/sound driven animations to my Xmas tree but ran out of time.
I need to go back into it soon but took some note about how much noise I got out of the mic output. I noted that I should look into supplying the microphone’s required DC bias with batteries instead of from the +5Vdc. Also noted that I needed to lower the amplification out of that LM386 based audio amplifier but did not note by how much.
I remember that I still got it working satisfactorily even when running everything from the 5Vdc. Got good frequency response but with a lot of fluctuations.
Hope this helps…

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Having all the values so close to each other possibly indicates having the STROBE and RESET signals swapped.

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I have used SparkFun’s electret BOB with the MSGEQ7 before, with good results. I didn’t see any incompatibility. The MSGEQ7 stores its own internal ground reference on that capacitor attached to GND, so it’s pretty sensitive to any noise on the supply rails (something you’ll find aplenty with circuits involving PWMed LEDs).

I’m finishing up a small board with mic+amp+MSGEQ7 that seems to work fine on both 5V and 3.3V supplies:
https://dl.dropboxusercontent.com/u/610802/Screen%20Shot%202015-11-22%20at%205.13.16%20PM.jpg

https://dl.dropboxusercontent.com/u/610802/Screen%20Shot%202015-11-22%20at%205.11.41%20PM.jpg

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I have used a Max4466 electret mic for my spectrum analysis project. Not an MSEQ-7, but FHT in software. Here’s my schematic:
Imgur

The key points are a 330ohm resistor between the output data pin (to protect the neopixels), a 1000uF cap across 5v power and VCC connected to AREF for the mic.
Here’s video. https://www.youtube.com/watch?v=SRKjWxF8JG8

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The +5V line on a lot of USB hosts (especially cheap power banks) can be quite noisy – using the 3.3V regulator output from a microcontroller board can often help with this. You might also try using your own 3.3V reg if your board doesn’t have a 3v3 pin.

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I’m pretty sure it’s not noise on the power line from switching LEDs, as there are no LEDs connected at this point :-).

Everything is running off the 5V from my Macbook’s USB, so I’m guessing that is pretty clean.

@Garrett_Mace , that board looks awesome! Good thought about swapping STROBE and RESET but that doesn’t appear to be the case. Hmm.

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Hi @Robert_Atkins , just now re-assembled quickly my setup that consists of a small electret microphone, the LM386 based audio amp module and the MSGEQ7.
Working with the MEGA that I have to use for my Xmas tree and got it working nicely enough again. Each frequency band is independant enough. Everything powered from the same 5V PSU that also supplies he LEDs !
I got my MSGEQ7 from eBay and I read that they could be flaky maybe you just got a bad device !?

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I have heard of counterfeit or bad MSGEQ7 chips as well, especially if sourced from eBay. It’s easy to get the chips directly from MSI if you’re willing to buy 100 pieces. Otherwise I’d stick with SparkFun or similar caliber suppliers.

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@Robert_Atkins : Don’t guess, measure! Even expensive equipment can have design flaws – or faulty components.

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Good point @Luminous_Elements … still need to get myself that scope then :-/

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Cracked it, finally! Helps if you use the correct value components—I had a 330nF cap from pin 8 to ground, rather than a 33pF. Thanks all for the help.

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@Garrett_Mace Are you selling those boards?