how did create ph meter voltage formula ???

anonymous 2018-07-12 20:33:10 1904 Views1 Replies
Hi, my name umarjunaid i have your ph meter module and sample arduino code.i review it for understanding but i can't find how do you come up with volatge formula pHValue = 3.5*voltage+Offset;. and if we are using 3.3v microcontrol then this formula changes or not please tell me

2018-07-13 16:55:47 If you use 3.3V board, then the code need to be changed to "voltage = avergearray(pHArray, ArrayLenth)*3.3/1024;". the number 3.5 is because the output of the probe is -0.4V~0.4V, after amplification, it become 0~4V correspond to pH 0~14, 14/4 =3.5. robert.chen