3 of 9 sensors "saturating"

lhimo88
Posts: 3
Joined: Tue Aug 07, 2018 10:05 pm

3 of 9 sensors "saturating"

Postby lhimo88 » Tue Aug 07, 2018 10:15 pm

Hi there! I managed to connect and plot the signal from 9 of these sensors. They seem to work fine, except for the last three of them which are kind of saturating. In the screen attached you can see the spikes when I dip the working sensors in water, the central one seems to be not functioning for some reason, and the last three which indicate a constant value. What can it be?

Image
Last edited by lhimo88 on Wed Aug 08, 2018 5:10 pm, edited 1 time in total.

WiFive
Posts: 3529
Joined: Tue Dec 01, 2015 7:35 am

Re: 3 of 9 sensors "saturating"

Postby WiFive » Wed Aug 08, 2018 2:33 am

Image

ESP_Sprite
Posts: 8921
Joined: Thu Nov 26, 2015 4:08 am

Re: 3 of 9 sensors "saturating"

Postby ESP_Sprite » Wed Aug 08, 2018 3:19 am

I assume these are connected through the ADC of the ESP32? To which pins specifically? How did you set the gain in the ADC? If you connect a multimeter to the output of the sensors, what's the output of the good and the offending sensor? Have you tried exchanging the good and a wrong sensor and seeing if the graph moves along?

lhimo88
Posts: 3
Joined: Tue Aug 07, 2018 10:05 pm

Re: 3 of 9 sensors "saturating"

Postby lhimo88 » Wed Aug 08, 2018 5:14 pm

The working pins I'm using are GPIO 32,33,34,35,36 and 39. Therefore I'm missing other 3 pins, I tried GPIO 25,26,27 and GPIO 0,2,4 with the saturating behaviour.

lhimo88
Posts: 3
Joined: Tue Aug 07, 2018 10:05 pm

Re: 3 of 9 sensors "saturating"

Postby lhimo88 » Wed Aug 08, 2018 8:39 pm

P.s. I'm reading analog values with:

Code: Select all

#define ANALOG_PIN_8 2
int analog_value_8 = 0;
  analog_value_8 = analogRead(ANALOG_PIN_8);

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