PH meter

[mesuty]

Hi friends,
I am trying to implement a PH meter.

Does anybody have info ?

especially for sensor interface circuit.

Thanks

[Ttelmah]

Talk to the manufacturer of the sensor.
Most will have 'example' circuits, giving 4-20mA outputs, and 0-1v. The latter will scale easily to give 0-2.5v, and with a nice accurate bandgap reference giving this as the Adc reference, this can be read directly. The circuitry needed will depend on the accuracy you require, and the technology of the sensor. Some manufacturers offer ones with integrated electronics, and these are often not that much more than the 'bare' sensor, making things much more easy to do, and allowing other sensors with similar drives to be substituted.

Best Wishes