hello, after making the arduino circuit with npk sensor, there is an error in the codes I used, the values of 255 are displayed on the screen, can anyone help me?
Thanks in advance.
i use the code and circuit from this link.
Do your research, as those sensors are fakes.
They estimate soil conductivity and make up some numbers for N, P and K that seem reasonable. Sadly, 255 is an equally valid result.
It is impossible to measure three different ion concentrations with three metal electrodes.
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