February 18, 2014
We’ve been tinkering with feedback loops thus we needed a simple way to read a audio signal into Arduino. This is the simplest circuit. Once you plugged your sound source in (phone, computer, mp3 player …) you might want to turn the volume right up as it needs a strong signal.
The circuit is made of two 100 Kilo Ohm resistors and two capacitors (10uF, 4.7nF) it is very simple. What is does is to shifs the audio signal that oscillates around 0 volts 2.5 volts up. So it oscillates now around 2.5 volts allowing you to access the full wave form and not only the positive part of the signal.