analoge input problem

Hi

Does Arduino read input negative values (sine wave) or just positive values ?

sayedhasan1: Hi

Does Arduino read input negative values (sine wave) or just positive values ?

Well let's put it this way, it reads signals between 0V and 5V....

If you want to read sin waves you have to apply a DC offset using two equal size resistors between the rails and AC couple into this. That means using a capacitor. Like the input part of the schematic on this page. http://interface.khm.de/index.php/labor/experimente/arduino-realtime-audio-processing/