Arduino Forum

Using Arduino => Audio => Topic started by: harshvardhan on Feb 03, 2013, 04:23 am

Title: amplifying mic signals in an arduino
Post by: harshvardhan on Feb 03, 2013, 04:23 am
i researched google quite a bit to get something to amplify the signals of a mic.
i have been thinking, what is the problem of using an op amp?
wont that work?
Title: Re: amplifying mic signals in an arduino
Post by: CrossRoads on Feb 03, 2013, 04:41 am
Op amp would be fine.
Use one that will work with a 0/5V supply, bring your mic in thru a capacitor to an input pin; use 2 10K resistors to have the pin sit at 2.5V.

http://www.electronics-tutorials.ws/opamp/opamp_3.html

Title: Re: amplifying mic signals in an arduino
Post by: harshvardhan on Feb 03, 2013, 07:18 am
please show me the breadboard view of the schematic with the ca3140 .
also, wont a simple transistor work?
Title: Re: amplifying mic signals in an arduino
Post by: Grumpy_Mike on Feb 04, 2013, 09:57 pm

please show me the breadboard view of the schematic with the ca3140 .
also, wont a simple transistor work?


Don't get greedy, it is such a simple circuit it will do you good to lay it out yourself.

No you can't get that much gain out of a single transistor.
Title: Re: amplifying mic signals in an arduino
Post by: andygrove on Feb 17, 2013, 03:46 pm
You might consider buying an op-amp breakout board like this one for $5:

https://www.sparkfun.com/products/9816?

Or even better here is a breakout board with a Mic and a built-in amplifier for $8:

https://www.sparkfun.com/products/9964

I used the latter successfully in an Arduino project that took Mic input, applied a ring modulator effect, and then played the output on a speaker. Here is a link with circuit diagrams and code:

https://github.com/andygrove/arduino_dalek_ringmodulator

Hope that helps.