I am working on a project that requires input from a PH probe. I have found a few example circuits built around opamps but most output a -ve below PH7 and +ve above.
Could this be read by the Arduino analog in?
Could I modify this circuit - http://www.66pacific.com/ph/ph_3.htm
- that uses a 7V reference ground? I only need to measure PH values between 5 and 9 so perhaps I could change the reference ground to 2.5V so that the range fits the 5V input range of the Arduino?
Sorry that this is so open ended but I am trying to get to grips with this