Ok, I'm going to buy a ph probe and build a op amp circuit so my multimeter can read it, a simple circuit. was wondering if I could calibrate it with distilled water and ammonia. I understand I need to calculate the slope and the offset from ph 7. I have several PIC microcontrollers that can do the conversions or just a quick program on the computer or my programmable calculator. I evently plan on expanding it to be a controller, but do not like the stuff on the market, can't interface the standard PH controllers to a computer for logging of data, well you can for $500 bucks.
I've found some standard probes for $33, has anyone found any cheaper prices than this?
For those that are interested in hooking up PH probe to there multimeter here is opamp circuit.
http://alfaie.virtualave.net/electro...suring/m6.html
