Hello, I'm new to programming, and I have a question regarding a pH sensor and my ESP32. If the sensor signal is up to 5V, but my ESP32 only reads up to 3.3V, how do I make my ESP32 read the entire signal? Is a resistor useful to reduce the voltage? Can I power this module with 3.3v so that the esp32 can read it?
The module I'm using is "PH-4502C Analog pH Module"
And the probe I'm using is "PH Electrode Probe BNC E-201"
I would try using a simple voltage divider.
PH-4502C -> 1K -> ESP -> 1K -> 1K -> GND
This will reduce any voltage from the sensor by 33%
No, 5V only.
But that doesn't affect the PH-4502C module? Because I would be reducing the operating voltage if I connect the resistors to GND.
Connect the PO analog output via a voltage resistor to the ESP32. and Vcc of the sensor to 5v.
(seemed obvious, silly me)
Oh, okay, now I understand you. Thanks for your recommendation, but in the end, does that not affect the voltage signal? Or does it just reduce the voltage and when we measure pH the value will vary but this time with a smaller voltage range?
exactly that. 5v will be 3.3v 2.5v will be 1.6v. Keep in mind you will still need to calibrate the sensor the way it is described in the tutorials you find.
Thanks for your reply. Now I have a question, I was doing some research and discovered the Level Shifter. Can I use the TXS0108E level Shifter to directly reduce the 5V to 3.3V and the voltage varies when the sensor sends signals at different voltages?
No you cannot. That level shifter is for digital signals only. The To an Po outputs from the PH board are Analog.
As @jim-p says, but let me elaborate a little more. The analog signal varies between 5v & 0v initially. The voltage divider reduces the output by 33% . For the opposite effect (whenever you may need it, not in this project so far) you can use an Op-Amp. You could also use an OP-Amp to do the reduction, and in certain situations that is preferred. An Op-Amp has no influence on the circuit it is amplifying. A voltage divider does. In this case a voltage divider does the trick, and it's simpler.
In many cases a voltage divider is also the easiest way to reduce the logic levels of a digital signal.
A level shifter, however great it may be at times, is usually not required. Anyway, the voltage divider does the trick. You could also use 10K resistors, that does require a little less power. For digital signal, the higher value tends to cause issues with high speed. For analog voltages i guess it's not that important.
gustr:
Hai semuanya,
saya mengalami masalah yang hampir sama dengan carlosboli. akan tetapi saya menggunakan sensor ph 4502c dan esp8266
Ketika saya melakukan kalibrasi melalui serial monitor pembacaan P0 sambil memutar potensiometer, terkadang nilainya tidak turun hingga 2,5V. Nilainya hanya berhenti di 2,62V atau semacamnya, bahkan saat saya masih memutar sekrup dan ketika saya mengukur tegangan dengan multimuter dan memutar potensiometer tegangan naik turun 2,5V tidak stabil
Apakah ada yang menemukan solusinya dan bantu saya?
