Hi guys, I uploaded the example program with the potentiometer on the board. Works fine.
I disconnected everything except the USB cable from the board but my arduino says prints numbers around 300-400 on the serial monitor.
Why is this happening? Electrons going through air or something silly like that?
Float = picks up noise from surrounding environment - a fact of life with extremely high impedance circuits like an arduino input.. The internal pull up resistor isn't enabled by default because you may wish to use an external pullup or pulldown resistor, a pullup resistor will also interfere with any external circuit you wish to connect to the analogue pin. Its also inappropriate if you decide to use the analogue inputs as digital outputs).