Two voltage measurements using Arduino (need two different grounds)

Discussion in 'Embedded Systems and Microcontrollers' started by akazemian, Feb 25, 2016.

  1. akazemian

    Thread Starter New Member

    Feb 12, 2016
    Hi There,
    I need to measure two voltage readings using Arduino... I use analog pins A0 and A1 to do that.... when I only do one measurement (a wire from pin A0 -or A1- and a wire from Ground) everything is fine and voltage reading is correct (I check that with multimeter), but when I do them both (four wires-two from ground pins) then the numbers are inaccurate. It makes sense since the ground potential level for two readings is not the same but I connect them both to ground of Arduino. I will be grateful if someone can tell me how to fix this problem. For some reason I must use only one Arduino to do this task.
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
    Use the same ground pin for the two ground wires.