Hi, I need your help, please: I don't understand why my pre amp is not working, I've tried many configurations, the one attached being the last one, but I don't get much amplitude boost on the signal detected on the arduino side.
I don't have an oscilloscope and I'm using my laptop/mobile phone to generate a test sinewave.
The goal of the project is to have my Arduino Uno identify two sine wave frequencies and amplitudes, separately for left and right channel. Sine wave frequencies are going to be low, something between 50 and 200Hz, even lower if needed due to Arduino processing speed.
Because the source of those waves is going to be a mobile phone (candidates are iPhone/iPod and Android phones) the input should be something around +/-200mV which I wish to boost and shift to 0-5V for the Arduino to correctly process them.
If necessary the sine waves can be changed to chainsaw or square waves to simplify identification.