Cycling 74 » Topic: mic sensors

mic sensors

seanhorchy@gmail.com — Fri, 25 Sep 2009 03:18:23 +0000

Does anyone know how to get info from a mic into the Make Controller and Max? I don’t need the audio just the signal level.

I’m working on a tracking program using stereo sound and a servo motor. It seems simple to me, but I’m having trouble finding the resources.

Thanks,
Sean

Re: mic sensors

seanhorchy@gmail.com — Wed, 09 Dec 2009 04:07:59 +0000

Does anyone know how to use a mic as a sensor. I have two little mics i want to tell the difference in volume to control a servo motor to move towards the sound. I’m using a make controller, 2 miniature mics and max msp. I know how to control the servo but can’t figure out how to get values from the mics through the controller and into Max.

Any tips or which ports to use on the controller would be much appreciated.

thanks,

sean

Re: mic sensors

MIB — Wed, 09 Dec 2009 04:42:58 +0000

The easiest way to get volume from a signal is using the meter~ object.
Hope this helps.

– Pasted Max Patch, click to expand. –

Re: mic sensors

seanhorchy@gmail.com — Wed, 09 Dec 2009 18:31:01 +0000

Thanks MIB
The patch is helpful. I think my question is more on the hardware side. I am having a hard time figuring out how to hook up the miniature mics to the controller board so that I can get the values in Max. Perhaps I need to build another circuit to amplify the signal. I could use the patch you sent if I was using regular mics and some sort of digital interface, but I am trying to do this on the small side so that I can embed the circuit into a small plastic deer, and put the mics into its ears so that it will turn its head toward the sound.

Sean

Re: mic sensors

mzed — Wed, 09 Dec 2009 19:15:29 +0000

The momentary voltage from a microphone fluctuates very quickly, and is going to be a fairly meaningless value (especially at a low sample rate). You’ll want some sort of peak or envelope detecting circuit between the mic and the board. This is heading in the right direction:

http://freecircuitdiagram.com/2008/09/09/precision-full-wave-peak-detector-detect-the-envelope-of-an-audio-signal/

Re: mic sensors

seanhorchy@gmail.com — Wed, 09 Dec 2009 21:05:48 +0000

I’ve ben looking into 386 op amp circuits. Do you think that would give me a signal to use with arduino or MAKE controller?

Re: mic sensors

seanhorchy@gmail.com — Wed, 09 Dec 2009 21:09:16 +0000

And I’ve found some simple preamps using 741 circuit http://www.reconnsworld.com/audio_electretamp.html

does anyone think this would work?

Re: mic sensors

Andrew Benson — Wed, 09 Dec 2009 22:10:01 +0000

That will work to amplify, or scale the voltage (which will be necessary), but as mzed mentioned, you will need a peak detector to smooth out the signal enough to get useful values from your ADC.

Re: mic sensors

seanhorchy@gmail.com — Wed, 09 Dec 2009 22:46:05 +0000

thanks guys I really appreciate your help. I’m off to radioshack. I’ll try the circuit mzed suggested. Is the peak detector in addition to the amp circuit and am I right in understanding this flow?
mic to amp circuit then to peak detector then to arduino or MAKE controller.
Has anyone used the sound sensor modules and sensor brick for the arduino. Just trying to think of a backup plan. The show is in less than a month and my electronics knowledge is limited.

Do you think it will be possible to program the make controller or arduino with max or some other language so I won’t have to use the computer in the sculpture?

ps I appreciate the tutorials you post Andrew

Re: mic sensors

Andrew Benson — Thu, 10 Dec 2009 05:01:07 +0000

I find this online tutorial really helpful for dealing with sensor conditioning electronics.

Re: mic sensors

seanhorchy@gmail.com — Sat, 12 Dec 2009 02:28:25 +0000

Thanks for the link Andrew. I think I’m going to hold off on the robot project and focus on an instrument that uses a metal spiral staircase and contact mics as actuators under each of the steps. I’m more comfortable in Max than this Arduino/circuit realm.

Contact mics are an analog signal right? Id like to be able to use the velocity of the person walking up the stairs.
Thanks for your help.

Sean