Why most voltmeter/battery voltage read projects always use A0 as input?

I have been working on a project were I need to read the voltage of my 3.7v lipo battery to keep track of how much charge is left in the battery.

I have read countless topics on this matter and I have noticed something in common: all of them use the Analog pin A0 for the voltage input, why?

I'm new to arduino, but I have read that all pins from A5 to A0 are ADC, so wouldn't it be the same to use any other analog pin aside from A0 ?

Wild guess: it's the first one?

And although A5 is also a "first" one if you count from the right, it's maybe prudent to keep A4 and A5 vacant for using I2C.

Hi,
The same reason you label resistors R1, R2, R3 and Diode D1, D2, D3 its just convention and helpful when looking at more than one of a circuit feature.
It also makes locating components on PCBs if they are consecutively numbered, R4 will most possibly be near R3 and R5.

Tom… :slight_smile:

xXxOlivierxXx: all of them use the Analog pin A0 for the voltage input, why?

Just imagine the questions we would get if they all used A3!

Well why did we have a UNO and not a TRIO? ? ?