@FreshlySqueezed
So i made my pH meter sensor and calculated everything. (I got the reading from a voltmeter)
In pH 10 it gives a value of -144.72mV(-0.144.72mV)
In pH 7 it gives a value of 12.48mV(0.01248V)
in pH 4 it gives a value of 169.48mV(0.169V)
I read the tread and the post. You need to re-design the op-amp circuit.
An analog pin received a min voltage of 0 V to max voltage of 5 V. So you need to build a circuit using op-amp to "convert" the input voltage to a proper output voltage.
Let see... let take the extreme values : lower point --> ph 10 = -144.72 mV ---> 0 V
higher point --> ph 1 = 326.68 mV --- > 5 V
Assuming the values ( ph ) are linear, so use the linear formula ==> y = m * x + b
x is the input voltage, y is the output voltage m is a slope. And let figure out a formula using op-amps. Op-amps are Analog Computer. It can multiply a value, add and substract.
So the linear formula is : y = ( 10.60670344 * x ) + 1.53500212
So V out = 10.0607 X V in + 1.535 V The 10.6067 is the Amplification factor.