As long as your pins ate not connected, they are «floating» which gives you random readings.
You should connect all your analog pins to ground to get a 0 reading while you don’t send 5v to the input.
As long as your pins ate not connected, they are «floating» which gives you random readings.
You should connect all your analog pins to ground to get a 0 reading while you don’t send 5v to the input.